Water

Items to include in a water purification kit:

• Poly canteens (1 quart)
• Sierra cup
• Water purification tablets
• Water purifier & extra filters
• Water bag, nylon
• Water bag liners, plastic
• Solar still
• Rubber surgical tubing
• Compression straps
• Plastic garbage bags
• Twist ties

Procedure:

1. Fill a container with water to be treated.
2. Place the container over a heat source, such as a fire, stove, or solar heater.
3. Bring the water to a rolling boil (a vigorous, continuous boil) at sea level for one minute. At higher altitudes, increase boiling time by one additional minute for every 1,000 meters above sea level.
4. Allow the water to cool after boiling to avoid burns and ensure safe consumption.
5. Store the cooled boiled water in a clean container with a lid, ensuring it is sealed tightly to prevent recontamination.

Notes:
• Boiling is effective against all microbial pathogens, including bacteria, viruses, and protozoa.
• Even heating to 60 °C for several minutes can kill most pathogens.
• Boiled water may taste flat due to the removal of dissolved gases during boiling.
• Ensure that the container used for boiling is clean and free from contaminants.

Warnings:
• Avoid burns by using caution when handling hot containers.
• Be mindful of indoor air pollution caused by smoke, especially in enclosed spaces.

Procedure:

1. Identify a water source that is safe for use (e.g., stream, river, or well) and test it if possible.
2. Collect water using clean containers to avoid contamination during collection.
3. Boil the water for at least 1 minute (or 3 minutes at higher altitudes) to kill bacteria, viruses, and parasites.
4. Use chemical disinfectants such as chlorine tablets or bleach if boiling is not possible:
- Add 2 drops of liquid bleach per liter of water.
- Mix thoroughly and let stand for 30 minutes before use.
5. Filter the water using a portable filter, sand, charcoal, or cloth to remove particulate matter.
6. Store treated water in clean containers with tight-fitting lids to prevent recontamination.
7. Monitor the quality of the water regularly and repeat disinfection if necessary.

Steps to produce drinkable water using chlorine solution method:

1. Collect water from protected sources such as springs, taps, wells, tube wells, and boreholes.
2. If the water is dirty, ensure sediment deposit and/or use a sand filtration system.
3. Use 3 drops of chlorine solution (prepared by mixing 3 level tablespoons of bleaching powder in 1 litre of water) for each litre of water you want to clean.
4. Mix well and let the water stand for 30 minutes before drinking.

Note: This method is effective when chlorine solution is available and ensures safe consumption of water.

Steps to produce drinkable water using iodine method:

1. Collect water from protected sources such as springs, taps, wells, tube wells, and boreholes.
2. If the water is dirty, ensure sediment deposit and/or use a sand filtration system.
3. Add 10 mg of iodine (or 10 drops of tincture of iodine) to 1 litre of water.
4. Let the water stand for 15 minutes before drinking.

Note: This method is effective when iodine is available and ensures safe consumption of water.

Steps to produce drinkable water using purifying tablets method:

1. Collect water from protected sources such as springs, taps, wells, tube wells, and boreholes.
2. If the water is dirty, ensure sediment deposit and/or use a sand filtration system.
3. Use water purifying tablets (check the instructions for use provided by the manufacturer).
4. Follow the specific dosage and waiting time as indicated on the packaging before consuming the water.

Note: This method is effective when purifying tablets are available and ensures safe consumption of water.

Steps to produce drinkable water using solar disinfection method:

1. Collect water from protected sources such as springs, taps, wells, tube wells, and boreholes.
2. If the water is dirty, ensure sediment deposit and/or use a sand filtration system.
3. Place a day’s supply of drinking water in clear plastic bottles or plastic bags securely closed in direct sunlight for 10 hours.
4. After 10 hours of exposure to sunlight, the water can be consumed the next day.

Note: This method is useful when fuel or wood is in short supply and relies on UV radiation from the sun to disinfect the water.

Procedure:

1. Add one tablet to a quart of water in a jar or canteen with a loose cover.
2. Wait 30 minutes for the tablet to dissolve.
3. Shake the contents thoroughly, allowing some water to spill out over the top and lips of the container to disinfect them.
4. Tighten the cover and leave it that way for the required time before using any of the water.

Purpose: Purify drinking water using bleach to remove viruses, bacteria, protozoa, and fungi.

Materials Required:
• Plain unscented household bleach (6% sodium hypochlorite)
• Measuring tool (drops or teaspoon)
• Water container

Steps:
1. Add 16 drops (1/8 tsp) of household bleach to each gallon of drinking water.
2. Allow the water to sit for 30 minutes after adding the bleach.
3. Check if the water has a noticeable bleach odor:
- If it does, the water is safe to use.
- If not, discard the water and find another source.

Notes:
• This method is not safe for infants until the water has been filtered through a good filter.
• Use only plain unscented household bleach (6% sodium hypochlorite) for this procedure.
• Ensure that the bleach used is from an unopened or newly opened bottle, as potency diminishes over time.

Procedure:
1. Dig a hole 9 feet away from the river bank.
2. Ensure that the hole is deeper than the river bed.
3. Allow water to seep through into the hole, which will help eliminate toxins.

Note: This method was historically used during conflicts and may not be effective for all types of contamination.

Procedure:

1. Dissolve one heaping tablespoon of chloride of lime in 8 quarts of water to create a stock solution.
2. Add one part of this solution to 100 parts of the water to be disinfected (e.g., 1 quart of stock solution per 100 quarts of water).
3. Wait at least 30 minutes before using the water.
4. Store the stock solution tightly corked in a cool, dark place, and renew it frequently.

Procedure:

1. Prepare a filter using a pair of drill trousers:
- Turn one leg inside out and insert it into the other leg.
- Tie the cuff securely to create a sealed chamber.
- Use three stakes to hold the open top of the filter in place, driven well into the ground.

2. Fill the filter with polluted or dirty water.

3. Add hot stones to the water inside the filter:
- The heat from the stones will cause the water to boil and sterilize it.

4. Catch the filtered water in a separate container below the filter.

5. Pour the water back into the filter repeatedly until all dirt has been removed and the water has boiled for at least 10 minutes.

6. Drink only after the water is fully purified:
- Remember that even moistening your lips with polluted water can make you sick or kill you.

Important Notes:
• This method works best in areas where water may be unsanitary (e.g., near cities or villages).
• Ensure the stones are sufficiently hot to cause boiling.
• Always use a clean container to collect the purified water.

Procedure:

1. In areas where water may be unsanitary (e.g., near cities or villages), always boil the water before drinking.

2. Alternatively, add a pinch of chloride of lime to the water for purification.

3. For very muddy, dirty, or stagnant water, use a filter made from drill trousers as described in the Hot Stones Method procedure above.

4. After filtering, ensure that the water is boiled for at least 10 minutes to fully sterilize it.

Important Notes:
• Chloride of lime can be used if boiling is not possible or practical.
• Always use a clean container to collect and store purified water.
• Avoid drinking any untreated water, even in small amounts.

Simple Mode of Purifying Water:

A tablespoonful of pulverized alum sprinkled into a hogshead of water (the water stirred at the same time) will, after a few hours, by precipitating to the bottom the impure particles, so purify it that it will be found to possess nearly all the freshness and clearness of the finest springwater. A pailful, containing 4 gallons, may be purified by a single teaspoonful of the alum.

Another method: To a hogshead of water a tablespoonful of a saturated solution of permanganate of potassa; this effectually destroys all organic matter. If the water retain a pink hue, put a stick or chip in it when the color will shortly disappear.

Materials Needed:
• Sterilization tablets (from a survival kit)
• Or boiling equipment
• Alternatively: condies crystals or iodine from a first-aid kit

Procedure:
1. Use sterilization tablets: Add the recommended number of sterilization tablets to the water, as per the instructions on the package.
2. Boil the water: If no tablets are available, bring the water to a rolling boil for at least one minute (or three minutes at high altitudes) to kill bacteria and pathogens.
3. Use alternative chemicals: If sterilization tablets or boiling is not possible, use condies crystals or iodine from your first-aid kit as an alternative method of neutralizing bacteria in the water.

Notes:
• Clear water does not necessarily mean it is free of harmful bacteria.
• Always ensure that any natural water you drink has been properly sterilized to avoid internal infection and fluid loss.

Procedure:

1. In tropical and semi-tropical regions, chlorine-releasing compounds may not be reliable due to environmental factors.
2. Use iodine water purification tablets containing the active ingredient Tetraglycine Hydroperiodine as an alternative.
3. These tablets are effective against all common water-borne bacteria and have been adopted by the U.S. military for standard use.
4. Ensure that the tablets remain dry and are stored in a tightly sealed container after opening.

Objective: Ensure safe drinking water to prevent illness.

Steps:
1. Purify all water from natural sources using one of the following methods:
- Use iodine tablets as directed on the package.
- Add a few drops of bleach (with 5-10% available chlorine) per liter of water and let sit for 30 minutes.
- Boil water for at least 5 minutes to kill pathogens.

Notes: Always purify water before drinking, even if it appears clear.

Materials Needed:
• Container with seawater
• Cloth or plastic sheeting
• Another container to collect fresh water

Procedure:
1. Boil the seawater: Place a container of seawater on a fire and bring it to a boil.
2. Catch steam: Use a piece of cloth or plastic sheeting to catch as much steam as possible from the boiling water.
3. Condense and collect: Ring out the cloth or allow condensation to occur, collecting the fresh water that drips into another container.

Notes:
• This method is less efficient than using tubing but can still be used in a survival situation.
• Any improvised setup (e.g., a plastic tent over the boiling container) can help trap steam and collect condensation.

Materials Needed:
• Container with seawater
• Tubing or rubber hose
• Seal material (e.g., aluminum foil)
• Cooling agent (water)
• Two containers (one for seawater, one to collect fresh water)

Procedure:
1. Prepare the seal: Fold a piece of aluminum foil into a cone shape with the small end facing the tubing. Secure the large end around the container using wire or another method to create an airtight seal.
2. Insert tubing: Push one end of the tubing through the seal and ensure it is secure by blowing into the loose end to check for leaks.
3. Set up distillation system: Place the sealed container with seawater onto a fire and bring it to a boil. Steam will be forced through the tubing.
4. Condense steam: Run the tubing through a cooling agent (e.g., water) to allow condensation of the steam into fresh water, which will drip into another container at the end of the tubing.

Notes:
• This method is efficient for producing fresh water from seawater in survival situations.
• Ensure that the seal remains intact throughout the process to prevent steam loss.

Procedure:

1. Use a heat source: Heat the suspect water to evaporate it.
2. Condense the vapor: Allow the steam to condense in a separate container, leaving impurities behind in the original vessel.
3. Collect distilled water: The condensed water is now purified and safe for drinking.
4. Use for seawater or contaminated sources: This method is particularly effective for obtaining drinkable water from seawater or heavily polluted sources.
5. Ensure proper setup: Use a heat-resistant container to hold the source water, and place a lid or cover over it with a collection vessel underneath to capture the condensed vapor.

Procedure:

1. Use a commercial heat treatment unit to purify water at lower temperatures:
- Treats 500 gallons of water per day.
- Cost is approximately $1 per 1000 gallons for energy.
2. Heat the water to 161° F (71.7° C) and maintain this temperature for 15 seconds.
3. Use heat exchangers to recover most of the energy used in warming the water, improving efficiency.

Notes:
• This method is similar to milk pasteurization and can be an effective alternative when boiling is not feasible.

Water can be contaminated by pathogens such as bacteria, viruses, and parasites.

### Steps:
1. Test water sources for pathogens, especially if the source is surface water or from a well with potential contamination risks.
2. Use boiling, chemical treatment (e.g., chlorine), filtration, or UV purification to eliminate pathogens.
3. Ensure that collection methods reduce the risk of introducing new contaminants into the water supply.
4. Regularly monitor and treat water sources, especially during times of high rainfall or environmental disturbance.

Procedure:

1. Determine volume of water to treat:
- One maxi-sized Puritabs tablet treats 25 litres of water.

2. Add the correct number of tablets:
- For large volumes, use chloramine T at a rate of 5mg per litre of water.

3. Wait for treatment to complete:
- Allow treated water to sit for at least 30 minutes before drinking.
- If the water is very cold, extend waiting time as needed.

4. Remove chlorine taste (optional):
- Use sodium thiosulphate to remove the taste of chlorine.
- Add it directly to a drinking cup at the point of use.
- Do not add it to storage containers like canteens or jerry cans, as this will inactivate the chlorine and compromise water safety.

Important Notes:
• Chlorine is ineffective against _Giardia_, _Cryptosporidium_, and amoebic cysts.
• Prior filtration may be necessary if water is alkaline, very cold, or contains organic matter.

Procedure:
1. Use copper sulphate to purify water in ponds.
2. Apply the chemical at a ratio of 1 million parts copper sulphate to 1 part water.

Note: This method is specific to regions like South America and should be used with caution due to potential toxicity if misapplied.

Procedure for Purifying Water Using a Three-Tier Filtration System:

1. Gather materials: Grass, sand, and charcoal (not ash). The charcoal should be at least 5-6 inches thick.
2. Construct the filter layers:
- Place the grass layer first to remove larger impurities.
- Add a second layer of sand to remove smaller impurities.
- Add the final layer of charcoal (not ash) to bond and hold toxins.
3. Use a straining device: All layers should be placed on some type of straining device.
4. Change layers frequently: Replace the filter layers regularly to maintain effectiveness.
5. Boil the straining material: The straining material should be boiled periodically to ensure it is free from contaminants.
6. Important note: This method does not disinfect water, and cysts may still pass through the system.

Purpose: Ensure that sediment and organic matter are removed before sterilization to improve the effectiveness of purification methods.

Procedure:
1. If water is cloudy or contains suspended matter, use a Millbank bag (a sock-shaped filter):
- Pour water into the bag.
- Allow it to filter by gravity through the weave.
- Hang the bag over a receptacle for continuous filtration.
2. Use two sizes of Millbank bags:
- 2-litre size for personal use.
- 9-litre size for large quantities of water.
3. Alternatively, let cloudy water stand in a jerry can or sedimentation tank for several hours to allow solids to settle.
4. For very fine particles like rock flour or mica flakes (common in glacial outflow), use a ceramic filter as these are gastrointestinal irritants and must be removed.

Notes:
• Simply clearing water does not sterilize it; further treatment is required before drinking.

Procedure:

1. Choose the right filter or pump based on needs:
- Consider pore size (measured in microns) – anything larger than 1 micron may not remove all organisms.
- Look for devices that combine filtration and chemical treatment for comprehensive purification.

2. Assess performance claims carefully:
- Manufacturers often state how many litres of pure water a device can produce, but this may be reduced in silty conditions.
- Be aware that some pumps do not remove chemical effluents (e.g., mercury) without the addition of a carbon filter.

3. Consider usability factors:
- For heavy use, choose a purifier that can be disassembled, cleaned, and reassembled in the field to prevent blockages.
- Check pump rate – some require significant effort to produce small amounts of water.

4. Use treated water promptly:
- After sterilisation, ideally consume purified water within 24 hours for best results.

Important Notes:
• Always verify the specifications and limitations of your chosen device.
• Be prepared to supplement with additional filters (e.g., carbon) if treating contaminated or chemically polluted water.

Procedure:

1. Use a solar pasteurizer to heat water using sunlight:
- Heats 3 gallons of water to 65° C (149° F).
- Maintain this temperature for at least one hour to ensure pathogen inactivation.
2. Rotate the device east to west during the day to follow the sun and increase heating efficiency.

Notes:
• This method is ideal for areas with abundant sunlight and no access to fuel or electricity.

Procedure:
1. Add 5 drops of Javel per 4.5 litres of water.
2. Never exceed this dosage, as it can cause an acidic taste in the water.

Warning: This method may leave the water with an acidic flavor, which could be unpleasant for consumption.

Procedure:
1. Drop a small piece of potassium permanganate into the water.
2. Ensure that the water is hardly tainted (i.e., only slightly discolored).
3. Wait for 1 hour before drinking the water.

Note: This method may leave the water with a slight pinkish or purple tint, which should fade over time.

Procedure:

1. Store iodine tablets in a dry place to prevent degradation.
2. Keep the bottle tightly recapped after opening to maintain potency.
3. Ensure that all containers used for water purification are disinfected and kept clean to avoid recontamination.

Procedure:

1. Purchase chemical purification tablets (e.g., Halazone) from sporting goods or drug stores.
2. Ensure the tablets are fresh and stored in a dry, tightly sealed container to maintain their effectiveness.
3. When using the tablets, follow the dosage instructions:
- Use one tablet per pint of water for general use.
- Use two tablets per pint if you are unsure about the safety of the water.
4. Let the water stand for at least 1/2 hour before drinking to allow full chemical reaction and purification.

Important Notes:
• Always check the expiration date on the tablet container.
• Store tablets in a cool, dry place away from moisture.
• This method is not suitable for heavily contaminated or radioactive water.

Procedure:
1. Collect charred hardwood from your campfire.
2. Drop several pieces into a boiling pot of water (from a swamp or pond with an unpleasant odor).
3. Simmer the water for 10 to 15 minutes.
4. Skim away any foreign matter that rises to the surface.
5. Strain the water through a clean cloth, or allow it to settle if time permits.

Note: This method helps both sweeten and purify the water in one step.

Testing and sealing a spring is essential for ensuring safe water use.

### Steps:
1. Test the water for pathogens, VOCs (Volatile Organic Compounds such as fuel oil or benzene), pesticides, and any other contaminants common in your area.
2. Seal the spring using a spring box to prevent contamination from surface runoff or environmental factors.
3. Divert surface runoff around the spring box to avoid introducing pollutants into the water source.
4. Periodically treat the spring box with chlorine, especially if the spring is slow-moving, to maintain water safety.
5. If using a spring-house for food storage or cooling, install a spring box inside the house to ensure access to potable water.

Purpose: Understand how to calculate chlorine dosages using tables that provide volume conversions for bleach, dry calcium hypochlorite (HTH), and concentrated calcium hypochlorite solutions.

Key Concepts:
• Chlorine Demand: The amount of chlorine consumed by the water before achieving a residual concentration. This depends on the water's chemical composition.
• Residual Chlorine: The remaining chlorine in the water after treatment. If there is no chlorine demand, the residual equals the dose. Otherwise, it will be lower.

Units Conversion Notes:
• 10 ppm = 10 mg/L (parts per million and milligrams per liter are equivalent).
• Always round up calculated values if your measuring device lacks precision to ensure you provide at least the intended dose.

Testing Requirements for Drinking Water:
• After adding chlorine, allow a 30-minute contact time before testing.
• Test the water to confirm that the desired residual has been achieved.

Procedure for Using Commercial Water Filters:

1. Understand the filter's capabilities: Know what the filter can and cannot do to safeguard against illness.
2. Check micron rating:
- A filter with a .3 micron opening or larger will not stop Cryptosporidium.
3. Chemical considerations:
- Filters that do not release chemicals (e.g., iodine) may not kill all pathogens.
4. Avoid overuse:
- Overused filters can become clogged, leading to excessive pumping pressure that allows harmful pathogens to pass through the filter opening.

Procedure for Using Contact Time with Halogen Chemicals to Purify Water:

1. Determine water temperature: Measure the temperature of the water in degrees Celsius or Fahrenheit.
2. Select appropriate contact time based on concentration and temperature:
- At 5°C / 40°F:
- 2 ppm: 240 minutes
- 4 ppm: 180 minutes
- 8 ppm: 60 minutes
- At 15°C / 60°F:
- 2 ppm: 180 minutes
- 4 ppm: 50 minutes
- 8 ppm: 30 minutes
- At 30°C / 85°F:
- 2 ppm: 60 minutes
- 4 ppm: 45 minutes
- 8 ppm: 15 minutes
3. Apply the chemical: Add the appropriate concentration of halogen (e.g., chlorine or iodine) to the water.
4. Allow contact time: Let the water sit for the required duration based on temperature and concentration.
5. Important notes:
- These times have been extended from usual recommendations due to recent data showing prolonged contact is needed in cold water to kill *Giardia* cysts.
- Chemicals may not destroy *Cryptosporidium*.

Materials Needed:
• Portable water filter (with ceramic and activated carbon granules)
• Intake hose
• Container to collect purified water

Procedure:
1. Set up the filter: Hold the portable water filter vertically.
2. Insert intake hose: Suspend the intake hose in the untreated water source.
3. Pump until water flows: Pump the filter until purified water begins to flow from the outlet.
4. Monitor and clean: As bacteria and particles become trapped on the surface of the ceramic filter, pumping will require greater effort. Clean the filter regularly but do not force it if resistance is too high.

Notes:
• Most portable filters are designed to remove bacteria such as Giardia, Cryptosporidium, Salmonella, E-Coli, and Cholera, as well as chemicals like chlorine and pesticides.
• These units typically do not desalinate seawater; check with the supplier before purchasing.

Halogen contact times for water purification vary based on temperature and concentration:

| Temperature | 2 PPM | 4 PPM | 8 PPM |
|-------------|-------|-------|--------|
| 5°C / 40°F | 240 | 180 | 60 |
| 15°C / 60°F | 180 | 50 | 45 |
| 30°C / 85°F | 60 | 30 | 15 |

NOTE: These contact times have been extended from the usual recommendations to account for recent data that prolonged contact time is needed in very cold water to kill _Giardia_ cysts.

WARNING: Chemicals may not destroy *Cryptosporidium*.

This method of purification removes organic and inorganic chemicals and particulate matter, including radioactive particles. However, it may not remove or kill microorganisms.

Procedure:

• Proven reduction in bacteria and protozoa levels in water.
• Reduces the incidence of diarrheal diseases among users.
• Does not require chemicals or fossil fuels, making it an environmentally friendly option.
• Simple to install and operate, requiring minimal training or technical knowledge.
• Removes turbidity, tastes, and odours from water without affecting its chemical composition.

Notes:
• Ceramic filters are a sustainable and low-cost method of water treatment in many settings.
• They are particularly useful for households or communities with limited access to electricity or fuel.

Overview:

For chemical disinfection, the key is the concentration of halogenation. The following table provides contact times based on temperature:

|Concentration of<br>Halogen|Contact time @<br>5°C / 41°F|Contact time @ 15°C / 59°F|Contact time @ 30°C / 86°F|
|---|---|---|---|
|2ppm|240 minutes|180 minutes|60 minutes|
|4ppm|180 min|60 min|45 min|
|8ppm|60 min|30 min|15 min|

Iodine Tabs (e.g., EDWGT, Potable Aqua, Globaline):
• 4 ppm: ½ tab per liter of water
• 8 ppm: 1 tab per liter of water
• Tablets should be gunmetal grey in color when used. If rust-colored, they are ineffective as the free iodine has combined with atmospheric moisture.
• Bottles should be kept well sealed and replaced often.

2% Iodine (Tincture of Iodine):
• 4 ppm: 0.2 ml (5 gtts)
• 8 ppm: 0.4 ml (10 gtts)

10% Povidone-Iodine (Betadine):
• 4 ppm: 0.35 ml (8 gtts)
• 8 ppm: 0.7 ml (16 gtts)
• Use solution only, NOT SCRUB.

Saturated Iodine Crystals:
• 4 ppm: 13 ml per liter of water
• 8 ppm: 26 ml per liter of water

Iodine Crystals in Alcohol:
• 0.1 ml / 5 ppm
• 0.2 ml / 10 ppm

Halazone Tablets:
• 4 ppm: 2 tabs per liter of water
• 8 ppm: 4 tabs per liter of water

Household Bleach (Clorox):
• 4 ppm: 0.1 ml (2 gtts) per liter of water
• 8 ppm: 0.2 ml (4 gtts) per liter of water

Important Notes:
• For very cold water, contact time should be increased.
• If drinking this water after disinfection, flavouring agents (drink mixes, etc.) can be added after the period allocated for disinfection. The disinfecting agent will bind to organic material and not work if added beforehand.

Procedure:

1. In areas where there is a likelihood of water being infected with bacteria, it is advisable to boil the water before drinking.
2. If boiling is not possible, add a pinch of chloride of lime (calcium hypochlorite) to the water.
3. This will chlorinate and sterilize the water, making it safe for consumption.

Notes:
• Chloride of lime can be found in some survival kits or obtained from natural sources.
• Always follow proper dosages to avoid over-chlorination.

Procedure:

1. If the water is muddy, add a pinch of alum to it.
2. The alum will cause the clay particles in the water to flocculate and precipitate, which will help clarify the water.
3. Allow the water to sit for at least 12 hours before use.

Notes:
• This method is effective but requires patience.
• Alum can be found in some survival kits or obtained from natural sources.

Materials Needed:
• Leg of trousers or shirtsleeve
• Fine sand
• Charcoal
• Gravel or small stones
• Container to collect filtered water

Procedure:
1. Create the filter: Use the leg of a pair of trousers or a shirtsleeve as an improvised filter.
2. Layer materials: Fill one third of the filter with fine sand, the next third with charcoal, and fill the rest with gravel or small stones.
3. Set up filtration system: Hang the filter in a tree or similar elevated position.
4. Pour water through the filter: Pour muddy or turbid water into the top of the filter.
5. Collect filtered water: Allow time for the water to pass through the layers and collect the clarified water that drips into a container placed underneath.

Notes:
• This method helps remove suspended matter from natural water sources.
• It is not sufficient on its own for sterilization; additional purification methods are required.

Procedure:

1. Assess the water source based on its environment:
- In mountainous or wooded areas, a lively bubbling stream that flows over rocks and sand for at least 30 feet is generally considered safe to drink.
- If you see livestock (e.g., cows) near the bend of the stream, it may be an indicator that the water is fit for drinking.

2. Use caution in polluted areas:
- As pollution increases, it becomes safer to purify all water rather than relying on natural indicators alone.

3. If unsure about the safety of the water, always purify it before consumption using boiling, chemical tablets, or filtration methods.

Important Notes:
• This method is not foolproof and should be used in conjunction with other purification techniques.
• Always prioritize safety when determining whether to drink untreated water.

Procedure:

• Ceramic filters are fragile and may break easily if not handled with care.
• Low effectiveness against viruses, requiring additional treatment methods for complete disinfection.
• Small cracks or fissures in the ceramic can reduce its ability to remove pathogens from water.
• No residual disinfection effect, increasing the risk of recontamination after filtration.
• Regular cleaning is required to maintain filter efficiency and prevent clogging.
• Not suitable for extremely turbid water, which may damage or block the filter pores.

Notes:
• Users must be trained on proper maintenance and handling procedures to avoid damage or inefficiency.
• Ceramic filters should not be relied upon as a sole method of water treatment in high-risk environments.

ERDLATOR is a transportable quick-response water purification system capable of aerating, clarifying, filtering and disinfecting contaminated water.

It is used in emergency or field situations where rapid deployment of a complete water treatment system is required. It ensures that water from any source can be made potable through its integrated processes.

Procedure:

1. Calculate fuel needed based on the following:
- It takes approximately 1 kg of wood to boil 1 liter of water.
2. Use hardwoods and efficient stoves to improve efficiency and reduce fuel consumption.

Notes:
• This estimate can vary depending on the type of wood and stove used.

Procedure:

1. If no artificial means are available, strain the polluted water through closely woven garments such as a felt hat or a pair of thick drill trousers.
2. To sterilize the water, add hot stones to the filtered water in the container.
3. The heat from the hot stones will cause the water to boil, making it sterile and safe for drinking.

Notes:
• This method is useful when no equipment is available.
• Ensure that the hot stones are fully submerged in the water.

Procedure:
1. If you are not accustomed to hard water, consume it in small amounts at a time.
2. Avoid consuming large quantities of hard water initially, as it may cause severe digestive upsets.
3. Boiling the water may help reduce some of its hardness and make it more palatable.

Note: It may take time to adjust to drinking hard water without adverse effects.

Procedure for Sol-Air Water Treatment:

1. Select appropriate containers: Use either glass or plastic bottles. Plastic bottles (preferably PET, not PVC) allow more UV radiation to pass through but may leach chemicals at high temperatures. Glass is more durable but less efficient in light transmission.

2. Fill the container: Fill the bottle 3/4 full with water that is as free of turbidity as possible. If using plastic bags or flat glass containers, they are ideal for maximizing solar energy absorption per unit of water.

3. Aerate the water: Cap the bottle and shake it vigorously for several minutes to introduce oxygen into the water. This step should be repeated every few hours during the treatment process to maintain adequate oxygen levels.

4. Expose to sunlight: Place the bottles upright in direct, unshaded sunlight where they will receive consistent exposure throughout the day. Ensure that the sun casts a distinct shadow (indicating sufficient intensity).

5. Monitor temperature: For optimal effectiveness, ensure water temperature is above 50°C (122°F). In colder climates, consider using solar collectors to increase water temperature.

6. Repeat shaking: Shake the bottles at least three times during the day to maintain oxygen levels and enhance microbial inactivation.

7. Duration of treatment: Allow the water to sit under direct sunlight for a minimum of 4.5 hours. In lab tests, this has been shown to reduce fecal coliform bacteria by up to 1000-fold.

8. Post-treatment handling: At the end of the day, allow the treated water to cool before consumption. It is most practical to consume the water the following day after it has cooled.

9. Daily treatment required: Due to the lack of residual disinfection, a new batch of water must be treated each day.

10. Clean and dry containers: After use, air-dry the bottles thoroughly to prevent algae growth if they will be reused.

Procedure:

1. Dig a hole:
- Dig a hole about one foot across and six inches deep below the water level, a few feet away from the pond or swamp.

2. Fill with water:
- Fill the hole with water from the pond or swamp.

3. Bail out the water:
- Quickly bail out the water, repeating this process about three times.

4. Collect filtered water:
- After the third bailing, the hole will fill with filtered water that is safe for consumption.

Note: This method relies on natural sedimentation and filtration through the soil to remove contaminants.

Objective: Prepare turbid water for treatment with the SODIS method by reducing turbidity.

Procedure:
1. Allow the water to settle: Pour the turbid water into a large container and let it sit undisturbed for several hours or overnight. This allows suspended particles to settle at the bottom.
2. Decant the clear water: Carefully pour off the clearer upper layer of water, avoiding disturbing the sediment at the bottom.
3. Use simple filtration if needed: If settling alone is not sufficient, use a basic filter made from sand and gravel or a clean cloth to remove remaining particles.
4. Test clarity again: After pretreatment, check the water’s clarity by holding it up to light. It should be significantly clearer than before.

Notes:
• Pretreatment improves the effectiveness of the SODIS method by allowing more UV light to penetrate the water.
• If turbidity is high or persists after settling, consider using a different purification method in conjunction with SODIS.
• Always ensure that any materials used for pretreatment are clean and free from contaminants.

Procedure:

1. If time permits, filter the stagnant water through a sieve made of charcoal.
2. This process will both clarify and to a large extent purify the water.
3. However, it is always safer to boil the water before drinking after filtering.

Notes:
• Charcoal sieves are effective for removing impurities.
• Boiling ensures complete sterilization of the water.

Bleach is a common method for purifying water in emergencies, though it has limitations due to its low active chlorine content and instability over time.

### Steps:
1. Use ordinary household bleach (such as Clorox) that contains 5.25% sodium hypochlorite (NaOCl). Ensure the product contains no other active ingredients, scents, or colorings.
2. Add 8 drops (0.4 ml) of bleach per gallon of water.
3. Allow the treated water to sit for 30 minutes.
4. Check if there is a slight chlorine smell; if not, repeat the treatment.

### Notes:
• Chlorine loss increases with agitation or exposure to air.
• A 5% solution may lose up to 10% of its chlorine content over 6 months when stored at 70° F (21° C).
• USP standard medicine droppers dispense approximately 0.045–0.055 ml per drop, so accuracy is important for proper dosing.

Calcium hypochlorite (also known as High Test Hypochlorite or HTH) is a highly effective method for purifying water in the field.

### Steps:
1. Use crystal form calcium hypochlorite, which contains nearly 70% available chlorine.
2. For large-scale systems, dilute HTH to make a 1% working solution: use 14g of HTH per liter of water.
3. To treat water:
- Use the 8 drops/gallon dosage or 1 part 1% solution to 10,000 parts clear water, which results in 1 PPM chlorine.
- If the water was not pre-filtered, increase the dose as needed.
4. After treatment, add hydrogen peroxide to drive off residual chlorine if desired.

### Notes:
• The US military and aid agencies commonly use HTH for bulk water treatment.
• A test kit is recommended to ensure proper chlorine levels (WHO standard: 0.2–0.5 mg/l residual chlorine after 30 minutes of contact time).

ROWPU (Reverse Osmosis Water Purification Unit) is the most common field purification system in use. It produces potable water from contaminated sources including fresh, brackish, or sea water. The finished water must be disinfected to eliminate viruses and protect the water from microbial contamination.

Setup and Components:
• Raw Water Pump (RP): Draws raw water into the system.
• Pressure Pump (PP): Increases pressure for the reverse osmosis process.
• Chemical Feeder (ChF): Adds chemicals to aid in purification.
• Reverse Osmosis (RO): Removes dissolved and suspended contaminants.
• Mixer (M): Combines chemicals with water.
• Brine Rotameter (BR): Measures brine flow.
• Filter (FI): Filters out remaining particulates.
• Disinfection Feed (DF): Adds disinfectants to the final product.
• Booster Pump (B): Increases pressure of purified water for distribution.
• Product Rotameter (PR): Measures the flow rate of purified water.
• Cartridge Filter (CF): Final filtration step before distribution.

Figure 9-2: Shows a basic water flow diagram through the various components of the ROWPU.

Procedure for Sedimentation of Water:

1. Allow water to sit: Let the water sit in a container without agitation for at least 1 hour.
2. Separate sediment: After sediment has formed on the bottom, decant or filter the clear water from the top.
3. Note limitations: Microorganisms, especially cysts, may eventually settle but this process takes longer and can be easily disturbed during pouring or filtering.
4. Important note: Sedimentation should not be considered a means of disinfection and is only suitable as a last resort or in extreme tactical situations.

Overview:
Home distillation involves boiling water and collecting the vapor that condenses back into purified water. This process removes most impurities, including salt, bacteria, heavy metals, and radionuclides.

Steps to Set Up a Home Water Distiller:
1. Choose a batch unit or continuous flow unit based on your needs:
- Batch units are ideal for small-scale use (e.g., 1-10 gallons per day) and are suitable for countertop or floor placement.
- Continuous flow units are connected directly to the water supply line and automatically produce distilled water as needed.
2. Ensure the distiller is made of materials that do not absorb impurities, such as stainless steel, aluminum, or plastic.
3. For batch units:
- Pour water into the boiling chamber.
- Turn on the unit and allow it to heat until all the water in the boiling chamber is evaporated.
- Once complete, remove the distilled water from the storage container for use.
4. For continuous flow units:
- Connect the distiller to your home’s water supply line using a float valve to maintain the water level in the boiling chamber.
- As distilled water is removed from the storage tank, the unit will automatically turn on and begin producing more distilled water.
5. Periodically remove concentrated impurities from the boiling chamber via a discharge line (for continuous flow units).

Storage:
• Store distilled water in sanitary conditions using plastic, glass, or stainless steel containers.
• Avoid storing distilled water for extended periods, as bacteria may re-colonize on cooling coils during inactive periods.

Limitations:
• Distillers do not effectively remove volatile organic contaminants (VOCs), certain pesticides, and volatile solvents that boil at temperatures close to water (207–218°F).
• Some distillers may allow up to 0.3 to 0.5% of impurities to remain in the storage container after distillation.

Efficiency:
• Distillers remove approximately 99.5% of impurities, including nitrates, bacteria, sodium, hardness, dissolved solids, most organic compounds, heavy metals, and radionuclides.

Steps to perform superchlorination:

1. Add sufficient chlorine (FAC) to the water in the container or pipe to achieve a concentration of at least 200 ppm.
2. Allow the FAC to remain in contact with the water for 4 hours.
3. Measure the FAC residual after 4 hours. The FAC must be at least 50 ppm at this time.
- If the FAC is below 50 ppm, repeat the superchlorination procedure.
4. Drain the container or pipes completely.
5. Rinse them thoroughly with water from an approved source.
6. Fill the containers or pipes with potable water from an approved source.
- In cases of scarce water supplies, it may be essential to use the superchlorinated water for drinking.
7. If dechlorination is needed:
- Use sodium thiosulfate or sodium bisulfite.
- Ensure large quantities are used as appropriate to protect the water from contamination.

Procedure:
1. Adding liquor to ice or water does not eliminate germs.
2. Germs can survive in ice and are not killed by alcohol.
3. Always ensure that drinking water is properly treated, boiled, or filtered before consumption.

Note: This method is ineffective for purifying water and may give a false sense of safety.

Turbidity is the presence of suspended solids in water and can be a significant issue for safe drinking water.

### Reasons Turbidity Is Problematic:
• Aesthetic considerations: Turbid water appears cloudy or muddy.
• Contamination risk: Suspended solids may contain heavy metals, pathogens, or other harmful contaminants.
• Reduced effectiveness of treatment methods: Turbidity can shield pathogens from chemical or thermal damage and absorb UV light in UV purification systems.

### Steps to Manage:
1. Use filtration techniques to reduce turbidity before treating the water.
2. Consider using coagulants such as alum to help settle suspended particles.
3. Ensure that water sources are not disturbed by erosion or runoff, which can increase turbidity.

Procedure:

1. Add Micropure tablets to untreated water:
- These contain Katadyne silver and are effective against bacteria but not _Amoeba_, _Giardia_, or viruses.

2. Avoid mixing with other treatments:
- Do not add Micropure tablets to water previously treated with chlorine or iodine, as this may reduce effectiveness.

3. Store treated water properly:
- The treatment is claimed to prevent recontamination for many weeks.

Important Notes:
• This method does not impart a bad taste to the water.
• It should not be used in conjunction with other chemical treatments.

Steps to disinfect water using iodine tablets in canteens:

1. Fill the canteen with the cleanest, clearest water available.
2. Add 2 iodine tablets per quart of water.
- For 2-quart canteens, double this amount (4 tablets).
3. If using tincture of iodine instead:
- Use 5 drops per quart of clean water.
- Use 10 drops per quart if the water is cloudy.
4. Place the cap on the canteen loosely and wait 5 minutes.
5. Shake the canteen vigorously to rinse the threads around the neck.
6. Tighten the cap and wait an additional 30 minutes before using the water for any purpose.

Important Notes:
• Iodine tablets must be inspected before use.
• Tablets that are completely yellow, brown, stick together, or crumble easily are no longer effective and should be discarded.

Procedure:

• Common technology that is widely understood and accessible.
• Complete disinfection if applied with sufficient temperature (at least 60 °C) and time.
• Can be combined with other activities such as cooking or making tea, reducing the need for additional fuel.

Notes:
• Boiling is a reliable method of water treatment in most environments.
• It does not require specialized equipment beyond a heat source and container.

Procedure:

1. Pour the water back and forth between two containers several times.
2. Repeat this process multiple times to aerate the water thoroughly.
3. This will help eliminate most of the chlorine taste from chemically treated water.

Important Notes:
• This method is useful after using chemical purification tablets like Halazone.
• If you are sensitive to chlorine, holding your breath while drinking can reduce the taste significantly.
• Aeration does not purify the water but improves its taste and quality.

Purpose: To purify water using solar energy.

Materials Needed:
• Clear plastic sheet or glass
• Container to collect distilled water (e.g., bowl)
• Source of contaminated water (e.g., soil, vegetation, or saltwater)
• Optional: Black tarp or dark material for absorption

Steps:
1. Prepare the Still: Place a container (to collect distilled water) inside a larger container or depression in the ground.
2. Add Water Source: Pour contaminated water into the smaller container, or place vegetation and soil around it to extract moisture.
3. Cover with Plastic/Glass: Cover the setup with a clear plastic sheet or glass, ensuring it is tightly sealed at the edges.
4. Create a Condensation Point: Place a small object (like a rock) in the center of the plastic/glass to create a low point for condensation to collect.
5. Seal Edges: Use soil or weights around the edges of the plastic sheet to ensure it is sealed tightly and does not lift due to wind.
6. Expose to Sunlight: Place the still in direct sunlight. The solar radiation will cause water to evaporate from the source, condense on the cover, and drip into the collection container.

Notes:
• Solar stills are most effective in sunny conditions.
• Output is typically low (30–16 oz per day under actual field conditions), but they can be critical when water is scarce.
• Avoid using WW2 surplus inflatable solar stills due to high failure rates.

Procedure:

• Boiled water may taste flat due to the removal of dissolved gases.
• Expensive in terms of fuel (firewood, gas, etc.) required for boiling.
• Time-consuming, requiring physical presence during the heating process and a long cooling time afterward.
• Does not remove chemical contaminants such as heavy metals or pesticides from water.

Notes:
• Boiling may be impractical in situations where fuel is scarce or when rapid access to clean water is needed.
• Environmental concerns related to indoor air pollution and deforestation should also be considered.

Purpose: Determine how much water is needed per person per day.

Procedure:
1. For adults in temperate climates, estimate 3 litres of water per person per day for drinking.
2. In hot climates, increase to up to 10 litres per person per day due to increased sweating.
3. Add an additional 4 litres per person per day for cooking and washing up.

Notes:
• These estimates are essential for planning water supplies at base camp and for field parties.
• Consider the number of people, climate conditions, and duration of the expedition when calculating total requirements.

Procedure:

1. Understand the limitations of heat treatment:
- It does not leave any residual protection against pathogens in stored water.
2. Re-treat water before consumption if it has been stored after purification, as it may become re-contaminated.

Notes:
• Always ensure proper storage conditions to minimize the risk of recontamination.

Overview:
Regular maintenance and cleaning of your home water distiller is essential to ensure the continued effectiveness of the unit and prevent bacterial growth.

Steps for Maintenance and Cleaning:
1. Turn off and unplug the distiller before beginning any cleaning process.
2. Empty the boiling chamber and storage container, ensuring that all residual water is removed.
3. Disassemble removable parts, such as the boiling chamber, condenser coils, and float valve (if applicable), for thorough cleaning.
4. Clean components with mild soap and warm water to remove any buildup or residue from previous use.
5. Rinse all cleaned parts thoroughly with clean, potable water to ensure no soap residue remains.
6. Inspect the cooling coils for signs of bacterial growth or mineral deposits. If present, clean them using a solution recommended by the manufacturer (often a mild acid or vinegar-based cleaner).
7. Reassemble the distiller, ensuring that all components are securely in place and properly aligned.
8. Sanitize the storage container where distilled water is kept to prevent contamination from bacteria or other microorganisms.
9. Check for leaks in the unit, especially around the boiling chamber, condenser coils, and discharge line (for continuous flow units).
10. Test the distiller by running a small batch of water through it and checking the output for clarity and purity.

Notes:
• Bacteria may re-colonize on cooling coils during inactive periods, so regular cleaning is essential.
• Ensure that all materials used in the distiller are compatible with the type of water being processed (e.g., avoid using plastic parts if processing highly acidic or alkaline water).

Objective: Demonstrate how evaporation and condensation can purify water.

Materials Needed:
• 4 cups of dirt or sand
• A dozen stones
• 2 quarts of water
• A large glass bowl with tall sides (mixing bowl)
• A short glass
• Clear plastic wrap
• A sunny day

Procedure:
1. Mix the Dirt and Water: Combine 4 cups of dirt or sand with 2 quarts of water in a large glass bowl with tall sides.
2. Position the Short Glass: Place a clean, empty short glass in the center of the bowl.
3. Expose to Sunlight: Take the bowl outside on a sunny day.
4. Cover the Bowl: Cover the bowl with clear plastic wrap and secure the edges with the remaining stones.
5. Add a Weighted Rock: Place one stone directly on top of the plastic wrap, positioned over the short glass.
6. Allow Time for Process: Leave the bowl in the sun for several hours.
7. Check Results: After several hours, inspect the short glass (it should contain relatively clean water free of mud) and the bowl (it should contain dried dirt).

Notes:
• This process mimics the natural water cycle where evaporation removes impurities from water, and condensation collects purified water.
• The plastic wrap represents the Earth's atmosphere, and the condensation forms clouds and rain in nature.
• If the plastic wrap is dirty, it can simulate air pollution, which may affect the purity of the condensed water.

Follow-Up Questions:
1. What are the two processes responsible for purifying the water? (Evaporation and Condensation)
2. Where else do you see condensation? (Cold drink outside on a hot day)
3. How does this process work on Earth?
4. What is the plastic wrap? (Our atmosphere)
5. What is the condensation? (Clouds and rain)
6. What would happen if the plastic wrap was dirty? (Air pollution)

Variation: Add food coloring to the water to demonstrate that this process does not remove all pollutants.

Sedimentation Process:

• Sedimentation is the separation of suspended particles by gravity.
• Allow water to sit undisturbed for at least 1 hour.
• After sediment has formed, decant or filter the clear water from the top.
• Microorganisms and cysts may eventually settle but are easily disturbed during pouring or filtering.

Important: Sedimentation is not a disinfecting method. It should only be used as a last resort or in an extreme tactical situation.

Procedure:

1. Assess available water sources:
- Choose between a bright clear stream and a pond full of dead leaves and peaty matter.
- Inspect the pond thoroughly to ensure it is free from contamination.
- Avoid streams unless you can be certain they are not polluted at any point above your location.

2. Understand water purification principles:
- Running water does not necessarily purify itself; standing water has a better chance of self-purification due to stagnation allowing disease germs to die out.
- Groundwater from wells or springs is generally safer than surface water, provided the well is in good, sandy soil with no cracks or fissures.

3. Inspect and protect wells:
- Ensure the well is protected below ground from contamination.
- Prevent surface drainage from flowing toward the well.
- Cover the well tightly to prevent entry of waste water.

4. Purify water if necessary:
- If no safe water source can be secured, purify it using boiling or other methods.
- Boiling will destroy all disease germs and make water safe for consumption.

Objective: Identify suitable bottles for the SODIS method.

Procedure:
1. Check bottle material: Only use PET (polyethylene terephthalate) bottles, which are marked with the symbol Ⓝ.
2. Inspect transparency: The bottle must be clear and not cloudy or discolored.
3. Check for scratches or damage: Avoid using bottles that are scratched, cracked, or otherwise damaged.
4. Size limitation: Ensure the bottle is no larger than three liters in capacity.
5. Avoid unsuitable bottles: Do not use colored, opaque, or heavily worn bottles as they may interfere with the SODIS process.

Notes:
• PET bottles are preferred because they allow UV light to pass through effectively.
• Damaged or scratched bottles can reduce the efficiency of the disinfection process.

Understanding Potable Water:

• Definition: Potable water is defined as a water source that, on average over time, contains a "minimal microbial hazard" and has an acceptable statistical likelihood of illness.
• Note: This does not guarantee complete safety from pathogens but indicates a reduced risk compared to non-potable water.

Coagulation/Flocculation agents are used to improve the clarity of water by removing suspended particles, which can help reduce pathogen levels and make subsequent purification methods more effective.

Procedure:
1. Determine the volume of water you need to treat.
2. Calculate the amount of coagulation agent (such as alum) required based on the dosage instructions: 10-30 mg per liter of water.
3. Add the calculated amount of coagulation agent into the water container.
4. Rapidly mix the solution to ensure even distribution of the coagulant throughout the water.
5. Agitate the mixture for at least 5 minutes to encourage the formation of flocs (clumps of particles).
6. Allow the treated water to settle for at least 30 minutes, allowing the flocs to fall to the bottom of the container.
7. Carefully pour off the clear water from the top, leaving the flocs behind.

Notes:
• This process can reduce coliform bacteria by 60-98%, viruses by 65-99%, and giardia by 60-90%.
• It also helps remove organic matter and heavy metals from the water.
• While effective, some question the safety of using alum due to concerns about aluminum toxicity. However, there is little scientific evidence to support these concerns, as virtually all municipal plants in the US use alum for this purpose.

Micropur Crystal is a powder-based purifier that can be used to treat large volumes of water.

• MC250: Use 1 packet per gallon of water, suitable for up to 250 gallons.
• MC2500: Use 1 spoon (approximately 1/4 tsp) per 25 gallons of water, suitable for up to 2500 gallons.
• MC12500: Use 1 spoon (approximately 1/4 tsp) per 250 gallons of water, suitable for up to 12500 gallons.

Procedure:
1. Determine the volume of water you need to purify.
2. Calculate the amount of Micropur Crystal required based on the dosage instructions above.
3. Add the appropriate quantity of Micropur Crystal into the water container.
4. Mix thoroughly to ensure even distribution of the purifying agent throughout the water.
5. Allow the treated water to sit for the recommended time (usually 30 minutes) before consumption or use.

Notes:
• Micropur Crystal is effective against bacteria, viruses, and protozoa.
• Always follow the dosage instructions to ensure complete purification.

Ozone is used extensively in Europe to purify water. Ozone is a molecule composed of 3 atoms of oxygen, formed by exposing air or oxygen to a high voltage electric arc. It is much more effective as a disinfectant than chlorine, but it leaves no residual levels of disinfectant after turning back into O₂. One source quotes a half-life of only 120 minutes in distilled water at 20° C.

Ozone is expected to see increased use in the US as a way to avoid the production of trihalomethanes. However, ozone can break down organic molecules into smaller ones that may serve as an energy source for microorganisms. If no residual disinfectant is present (e.g., if ozone is used as the only treatment method), these microorganisms will cause water quality to deteriorate in storage.

Ozone also changes the surface charges of dissolved organics and colloidally suspended particles, causing microflocculation of dissolved organics and coagulation of colloidal particles.

UV light has been known to kill pathogens for a long time. A low pressure mercury bulb emits between 30% to 90% of its energy at a wavelength of 253.7 nm, right in the middle of the UV band. If water is exposed to enough light, pathogens will be killed.

However, some pathogens are hundreds of times less sensitive to UV light than others. The least sensitive pathogens are protozoan cysts, such as Giardia, which may not be destroyed by many commercial UV treatment units. Fortunately, these are the easiest pathogens to filter out with a mechanical filter.

The efficacy of UV treatment is very dependent on the turbidity of the water. The more opaque the water is, the less light that will be transmitted through it. Treatment units must be run at the designed flow rate to ensure sufficient exposure and turbulent flow, not plug flow.

A major drawback of UV treatment is that damage done to pathogens by UV light can be reversed if the water is exposed to visible light (330-500 nm) through a process known as photoreactivation.

UV treatment, like ozone or mechanical filtering, leaves no residual component in the water to ensure continued disinfection. Any purchased UV filter should be checked to ensure it at least complies with the 1966 HEW standard of 16 mW·s/cm², with a maximum water depth of 7.5 cm. ANSI/NSF require 38 mWs/cm² for primary water treatment systems. This level was chosen to give better than 3 log (99.9%) inactivation of Bacillus subtillis. However, this level is of little use against Giardia, and of no use against Crypto.

The US EPA explored UV light for small-scale water treatment plants and found it compared unfavorably with chlorine due to:
1. Higher costs
2. Lower reliability
3. Lack of a residual disinfectant

Water treatment is the process of purifying water to make it potable. It may include one or all of the following processes:

1. Aeration, coagulation, flocculation (clarification), and filtration: These steps remove suspended solids from the water.
2. Reverse osmosis: This removes both suspended and dissolved matter, including organic and inorganic contaminants.
3. Disinfection: This eliminates microbial contaminants that are too small to be removed by filtration.

Hydrogen Peroxide can be used to purify water in an emergency if no other purification methods are available.

Procedure:
1. Determine the volume of water you need to purify.
2. Calculate the amount of hydrogen peroxide required based on the dosage instructions:
- For poliovirus: Use a 0.3% solution and allow it to sit for 6 hours.
- For rhinovirus: Use a 1.5% solution and allow it to sit for 24 minutes.
3. Add the calculated amount of hydrogen peroxide into the water container.
4. Mix thoroughly to ensure even distribution of the purifying agent throughout the water.
5. Allow the treated water to sit for the recommended time before consumption or use.

Notes:
• Hydrogen Peroxide is more effective against bacteria, but requires Fe+2 or Cu+2 as a catalyst to achieve optimal results.
• This method should only be used when other purification methods are unavailable.

Potassium Permanganate can be used to purify water in a pinch, though it is not recommended as a primary method due to its lower effectiveness and potential for leaving an objectionable color.

Procedure:
1. Determine the volume of water you need to purify.
2. Calculate the amount of potassium permanganate required based on the dosage instructions: 1 gram per liter (1000 ml) of water.
3. Add the calculated amount of potassium permanganate into the water container.
4. Mix thoroughly to ensure even distribution of the purifying agent throughout the water.
5. Allow the treated water to sit for the recommended time (usually 30 minutes) before consumption or use.

Notes:
• Potassium Permanganate is effective against bacteria and viruses, but there is no data on its effectiveness against protozoan cysts.
• It may leave a pink or brown color in the water, which can be objectionable.
• This method should only be used when other purification methods are unavailable.

To create a simple and effective water filter using household materials, follow these steps:

1. Prepare the container: Perforate the bottom of a 5-gallon can, large bucket, watertight wastebasket, or similar container with about a dozen nail holes. Punch the holes from the bottom upward, staying within about 2 inches of the center.

2. Add pebbles or substitute materials: Place a layer about 1 inch thick of washed pebbles or small stones on the bottom of the can. If pebbles are not available, twisted coat-hanger wires or small sticks can be used.

3. Add porous cloth: Cover the pebbles with one thickness of terrycloth towel, burlap sackcloth, or other quite porous cloth. Cut the cloth in a roughly circular shape about 3 inches larger than the diameter of the can.

4. Add soil layer: Take soil containing some clay (almost any soil will do from at least 4 inches below the surface of the ground). Pulverize the soil, then gently press it in layers over the cloth that covers the pebbles, so that the cloth is held snugly against the sides of the can. Do not use pure clay (not porous enough) or sand (too porous). The soil in the can should be 6 to 7 inches thick.

5. Add second layer of fabric: Completely cover the surface of the soil layer with one thickness of fabric as porous as a bath towel. A dozen small stones placed on the cloth near its edges will secure it adequately.

6. Support the filter can: Support the filter can on rods or sticks placed across the top of a container that is larger in diameter than the filter can (e.g., a dishpan).

7. Filter water: Pour contaminated water into the filter can, preferably after allowing it to settle as described below. The filtered water should be disinfected by one of the previously described methods.

Notes and Adjustments:
• If the filtration rate is faster than about 1 quart in 10 minutes, remove the upper fabric and recompress the soil.
• After several hours, the rate will be reduced to about 2 quarts per hour. When the filtering rate becomes too slow, it can be increased by removing and rinsing the surface fabric, removing about 1 inch of soil, and then replacing the fabric.
• The life of a filter is extended and its efficiency increased if muddy water is first allowed to settle for several hours in a separate container.
• After about 50 quarts have been filtered, rebuild the filter by replacing the used soil with fresh soil.

Purpose: Create a homemade microfilter using diatomaceous earth for water purification.

Materials Needed:
• Diatomaceous earth (sold for swimming pool filters)
• A container or filter housing that can hold the DE
• A pump or pressure source to achieve flow rate
• Optional: Filter media such as sand or gravel for additional filtration

Steps to Build:
1. Select a Container:
- Choose a container or filter housing that can securely hold diatomaceous earth and allow water to pass through it.
2. Prepare the Diatomaceous Earth:
- Ensure the DE is of the type used for swimming pool filters, not food storage (as noted in Alan’s note).
3. Insert the Diatomaceous Earth:
- Fill the container with diatomaceous earth, ensuring it is evenly distributed and packed tightly to remove turbidity and pathogens larger than 1 μm.
4. Add Optional Filter Media:
- If desired, add layers of sand or gravel below the DE for additional filtration and support.
5. Connect a Pump or Pressure Source:
- Attach a pump or pressure source to achieve a reasonable flow rate through the filter.
6. Test the Filter:
- Run water through the filter to ensure it is working properly and removing turbidity and pathogens effectively.

Notes:
• This DIY method can be useful in emergency situations where commercial filters are unavailable.
• Ensure that the diatomaceous earth used is not confused with food-grade DE, as they are different products.
• Pressure may be required to achieve a reasonable flow rate through the filter.

1) Perforate the bottom of a 5 gallon bucket, or similar container with a dozen nail holes even spread over a 4" diameter circle in the center of the container.

2) Place a 1.5" layer of small stones or pebbles in the bottom of the can. If pebbles aren’t available, marbles, clean bottle caps, twisted coat hangers or clean twigs can be used.

3) Cover the pebbles with one thickness of terrycloth towel, burlap sackcloth, or other porous cloth. Curl the cloth in a roughly circular shape about three inches larger then the diameter of the can.

4) Take soil containing some clay (pure clay isn’t porous enough, pure sand is too porous) from at least 4" below the surface of the ground (nearly all fallout particles remain near the surface except after disposition on sand or gravel.)

5) Pulverize the soil, then gently press it in layers over the cloth that covers the pebbles, so that the cloth is held snugly against the walls of the can. The soil should be 6-7" thick.

6) Completely cover the surface of the soil layer with one thickness of fabric as porous as a bath towel. This is to keep the soil from being eroded as water is being poured into the filter. A dozen small stones placed on the cloth near it’s edges will secure it adequately.

7) Support the filter on rocks or sticks placed across the top of a container that is larger then the filter can (such as a dishpan)

The contaminated water should be poured into the filter can, preferably after allowing it to settle as described below. The filtered water should be disinfected by some method.

Bacteria are smaller than protozoa and can cause serious diseases such as typhoid fever, cholera, diarrhea, and dysentery. To ensure effective filtration:

1. Use a filter with an absolute pore size of 0.2 μm or less.
2. Ensure the filter is designed to remove pathogenic bacteria such as *E. coli*.
3. Be aware that contamination by bacteria can lead to serious illness, including fatalities from dehydration caused by diarrhea.
4. Even though *E. coli* is relatively harmless compared to other pathogens, it may indicate the presence of more dangerous bacteria in the water supply.
5. In developed countries like the US, bacterial contamination is a concern but not typically lethal due to better sanitation and treatment systems.

Protozoa cysts are the largest pathogens in drinking water and can cause serious illness. To ensure effective filtration:

1. Use a filter with an absolute pore size of 1μm or less.
2. Ensure the filter is designed to remove protozoa such as *Giardia lamblia* (Giardia) and *Cryptosporidium* (Crypto).
3. Be aware that these pathogens can cause illness in vulnerable populations, including the young, elderly, sick, or immunocompromised.
4. In developed countries like the US, protozoa are not typically a major threat due to better wastewater treatment, but this could change during survival situations.
5. Protozoa have been found in up to 5% of vertical wells and 26% of springs in the US.

Note: Giardia and Crypto are not likely to be fatal to healthy adults, even if untreated.

Problem: Establishing a reliable water treatment system in rural areas can be challenging.

Solution:
1. Set up a gravity-fed slow sand filter from a spring:
- Pipe water directly from the spring into the slow sand filter.
- Treated water flows into a storage tank and is distributed downhill to users via gravity, ensuring continuous pressure.
2. If using a stream or pond as a source:
- Use an appropriately sized pump, pressure tank, and pressure switch to pump water directly into the filter.
3. After the storage tank, use another pump, pressure tank, and pressure switch to provide suitable pressure for end-users.
4. Optional additions:
- Install a chlorinator after the filter.
- Add an ultraviolet (UV) system after the filter for additional disinfection.
- Use a roughing filter before the slow sand filter if high turbidity or solids are expected.

1) Fill a bucket or other deep container 3/4 full with contaminated water.

2) Dig pulverized clay or clayey soil from a depth of four or more inches below ground surface and stir it into the water.

3) Use about 1 inch of dry clay or clayey soil for every 4" depth of water. Stir until practically all of the clay particles are suspended in the water.

4) Let the clay settle for at least 6 hours. This will carry the fallout particles to the bottom and cover them. Carefully dip out or siphon the clear water and disinfect it.

Viruses are the second most problematic pathogen in water after protozoa. They cannot be removed by mechanical filters due to their small size (ranging from 0.020 to 0.030 μm). To ensure safety:

1. Recognize that viruses are not typically a major threat in developed countries like the US, but can become a significant hazard during survival situations or when sanitation levels drop.
2. Viruses occur solely in humans and are not commonly found in animal waste, reducing the risk from animal sources.
3. Viruses have been detected even in remote areas, so it is prudent to consider virus removal as part of water treatment protocols.
4. Mechanical filters alone cannot remove viruses; additional methods such as boiling or chemical disinfection may be necessary for complete virus elimination.

Purpose: Purify water using the PUR Scout portable filter with iodine resin stage.

Specifications:
• Filter Stages: Iodine resin, 1.0 μm filter, activated charcoal filter
• Flow Rate: Not specified (assumed similar to other PUR models)
• Capacity: 200 gallons
• Price: $70/$35/$15 (depending on quantity)
• Weight: 12 oz

Steps to Use:
1. Prepare the Filter:
- Ensure the filter is clean and dry before use.
2. Submerge in Water Source:
- Place the filter into a water source or fill it with water from a container.
3. Pump Water Through the Filter:
- Use the built-in pump to draw water through all three stages: iodine resin, 1.0 μm filter, and activated charcoal filter.
4. Collect Purified Water:
- The purified water will flow out of the filter into your collection vessel.

Notes:
• This filter is effective at killing viruses due to the iodine resin stage.
• It also removes bacteria, protozoa, and improves taste with activated charcoal.
• Replace the filter after 200 gallons of use or when flow rate decreases significantly.

Purpose: Purify water using the Sweetwater Guardian portable microfilter with optional iodine resin stage.

Specifications:
• Filter Stages: Glass fiber and carbon filter (0.2 μm), optional iodine resin stage
• Flow Rate: Not specified (assumed similar to other Sweetwater models)
• Capacity: 200 gallons (main filter) / 90 gallons (iodine resin stage)
• Price: $60/$20 (depending on quantity)
• Weight: 11 oz

Steps to Use:
1. Prepare the Filter:
- Ensure the filter is clean and dry before use.
2. Submerge in Water Source:
- Place the filter into a water source or fill it with water from a container.
3. Pump Water Through the Filter:
- Use the built-in pump to draw water through the glass fiber and carbon filter (0.2 μm).
4. Optional Iodine Resin Stage:
- If virus removal is needed, add the iodine resin stage to the filter.
5. Collect Purified Water:
- The purified water will flow out of the filter into your collection vessel.

Notes:
• This model offers an optional iodine resin stage for virus removal, making it more versatile than other Sweetwater models.
• Replace the main filter after 200 gallons or the iodine resin stage after 90 gallons of use.
• The pump is well-designed but may require a few seconds to pull a captive pin for storage.

Purpose: Purify water using the lightweight and affordable Timberline Eagle microfilter.

Specifications:
• Filter Size: 1.0 μm
• Flow Rate: Not specified (assumed to be relatively high)
• Capacity: 100 gallons
• Price: $20/$13 (depending on quantity)
• Weight: 8 oz

Steps to Use:
1. Prepare the Filter:
- Ensure the filter is clean and dry before use.
2. Submerge in Water Source:
- Place the filter into a water source or fill it with water from a container.
3. Pump Water Through the Filter:
- Use the built-in pump to draw water through the 1.0 μm microfilter.
4. Collect Purified Water:
- The purified water will flow out of the filter into your collection vessel.

Notes:
• This is a lightweight and affordable option that only removes protozoa, not viruses or bacteria.
• It is much easier to pump than other filters but may be less effective in certain situations.
• Replace the filter after 100 gallons of use or when flow rate decreases significantly.

Procedure:

1. Select a clean piece of tightly woven cloth (e.g., cotton or linen).
2. Fold the cloth several times to increase its filtering capacity.
3. Place the folded cloth over a clean container and pour the turbid water through it.
4. Collect the filtered water in the container below.

Notes:
• This method is effective for removing large particulate matter but not for eliminating pathogens or dissolved contaminants.
• The effectiveness of the filter depends on the tightness of the weave; a very thick cloth may slow down the filtration process significantly.
• After use, the cloth should be cleaned and stored in a hygienic manner to prevent recontamination.

Procedure:

1. Determine the volume of water to be treated.
2. Calculate the required amount of coagulant (e.g., aluminum sulfate) based on the turbidity level of the water.
3. Add the calculated amount of coagulant to the water and mix thoroughly for several minutes to allow suspended particles to agglomerate into larger bodies (flocs).
4. Allow the flocs to settle at the bottom of the container over a period of time (typically 1–2 hours).
5. Carefully pour off the clarified water from the top, leaving the settled flocs behind.

Notes:
• This method is effective for reducing turbidity and improving the efficiency of subsequent filtration or disinfection steps.
• The effectiveness depends on proper dosing and mixing techniques.
• Coagulants may be difficult to obtain in some regions, making this method less practical in certain situations.

Filtration Purifying Process:

A three-tier system is used to purify water:

1. First Layer (Grass Layer): Removes larger impurities.
2. Second Layer (Sand Layer): Removes smaller impurities.
3. Third Layer (Charcoal Layer): Bonds and holds toxins. The charcoal must be from a fire, not ash, and should be at least 5-6 inches thick.

Important Notes:
• All layers should be placed on some type of straining device.
• Layers should be changed frequently.
• Straining material should be boiled.
• This is not a disinfecting method. Cysts can possibly move through this system.

Purpose: Provide high-quality water from surface sources using slow sand filtration.

Procedure:
1. Determine filter vessel requirements: Use 2 or more vessels that are 6 to 8 feet deep.
2. Install underdrain assembly: This collects the treated water after it passes through the filter media.
3. Add gravel support layer: Place a gravel layer around and over the underdrain to support the sand bed.
4. Apply sand layer: Add a 3-4 foot deep layer of sand on top of the gravel.
5. Install flow control systems: Use controls to regulate the filtration rate (0.04–0.16 g/ft² per minute) and maintain consistent water flow.
6. Include head loss measurement devices: These help monitor solids accumulation in the filter bed.
7. Maintain a supernatant layer: Keep a 3-foot layer of raw water above the sand bed to provide head pressure for filtration.

Notes:
• Slow sand filters are ideal for small rural homesteads or communities with limited resources.
• The Schmutzedecke, a biological layer in the top few inches of sand, is responsible for removing up to 99.99% of bacteria, viruses, and turbidity.
• Regular maintenance and monitoring are essential for long-term performance.

Purpose: Reduce turbidity and solids load before slow sand filtration.

Procedure:
1. Assess water quality: Measure turbidity levels using a nephelometric turbidity unit (NTU) meter.
2. Install roughing filters if necessary: If turbidity exceeds 20 NTU for more than a few days, install a roughing filter.
3. Select the appropriate filter type: Choose between upflow, downflow, or horizontal flow based on solids loading and cleaning method preferences.
4. Layer media correctly: Use course to fine gravel as the filter media to ensure effective particle removal.
5. Monitor performance: Roughing filters can reduce turbidity by 50-80%, significantly decreasing maintenance needs for slow sand filters.

Notes:
• Pretreatment is essential in high-turbidity environments or during seasonal fluctuations.
• Proper filter selection and installation are critical to long-term effectiveness.

Purpose: Keep slow sand filters functioning effectively by regularly cleaning the filter bed.

Procedure:
1. Monitor headloss: Use headloss meters or site glasses attached to the bottom of the filter vessel to observe water level changes.
2. Determine when to clean: Clean the filter when the water level in the site glass drops between 12 inches and 24 inches.
3. Assess cleaning frequency: Based on raw water quality, filters are typically cleaned every 2–10 weeks.
4. Perform cleaning process:
- Stop the flow of water to the filter vessel.
- Remove accumulated solids from the Schmutzedecke layer using a scraping or washing method (e.g., wet harrowing).
- Rinse the sand bed thoroughly with clean water to remove residual contaminants.
5. Restart filtration: Once cleaning is complete, resume normal operation and monitor performance closely.

Notes:
• Violent pressure changes during valve operations can disrupt filter function; avoid rapid flow rate adjustments.
• Use storage tanks to manage fluctuating usage demands and prevent overloading the system.
• Proper training for personnel is essential for efficient maintenance.

Problem: High turbidity (>20 ntu) can clog slow sand filters.

Solution:
1. Use sedimentation tanks to allow suspended particles to settle before filtration.
2. Install a gravel roughing filter, which can reduce turbidity by 50–80% and serve as effective pretreatment for slow sand filters.
3. Ensure the system is designed to handle high turbidity loads, especially if water sources are prone to sedimentation or erosion.

Problem: Slow sand filters are ineffective at removing organics and pesticides.

Solution:
1. Add a granular activated carbon (GAC) layer to the filtration system before the slow sand filter.
2. This significantly reduces organic carbon and pesticide levels in water.
3. Reduces chlorine demand, lowers costs, and minimizes the formation of trihalomethanes (THMs) during chlorination.

Activated carbon (AC) filters must be replaced regularly to maintain effectiveness:

1. Replace the filter after six months of use or after 1000 gallons of filtered water, whichever comes first.
2. If your unit has a water meter, it will automatically shut down when the recommended volume is reached.
3. Some filters are rechargeable with hot water (145°F) to release adsorbed contaminants, but their long-term effectiveness is uncertain.

Notes:
• Filters may need to be replaced more frequently than manufacturer recommendations if performance drops significantly.
• Always check for signs of reduced filtration efficiency, such as changes in taste or odor.

Procedure:

1. Prepare a container with layers of sand and gravel (larger particles at the bottom, finer particles on top).
2. Pour the turbid water into the container so that it passes through the sand and gravel layers.
3. Collect the filtered water from the bottom of the container.

Notes:
• This method is useful for removing large particulate matter but not for eliminating pathogens or dissolved contaminants.
• The materials required (containers, spigots) may be a limitation in resource-limited settings.
• Regular cleaning and replacement of the sand and gravel layers are necessary to maintain effectiveness.

Purpose: Create a low-tech, sustainable water purification system using natural filtration.

Materials Needed:
• Large container or pit (at least 24 inches deep)
• Clean sand (preferably fine to medium grade)
• Gravel
• Drain pipe or tubing
• Rough-surfaced material for filter walls (e.g., bricks, stones)
• Water source

Steps:
1. Prepare the Filter Container:
- Dig a pit or use a large container with a drain at the bottom.
- Ensure the sides of the container are rough to prevent water from bypassing the sand layer.
2. Add Gravel Layer:
- Place a layer of gravel at the bottom of the filter, ensuring it surrounds the drain pipe without touching the walls.
3. Add Sand Layer:
- Add 24 inches of clean sand on top of the gravel layer.
4. Allow Initial Run-In Period:
- Pour water slowly through the filter until a biological layer (schmutzdecke) forms on the surface of the sand. This process may take several hours or days, depending on conditions.
5. Use the Filter:
- Once the schmutzdecke is established, water can be poured into the top of the filter at a rate of 0.2 meters per hour (or 0.2 m³/m² of surface area per day). This ensures effective removal of pathogens and turbidity.
6. Maintain the Filter:
- The filter can be cleaned by scraping off the top layer of sand and replacing it with fresh sand when necessary. The gravel layer may also need cleaning if debris accumulates.

Notes:
• This method is ideal for long-term use in survival or emergency situations where access to advanced filtration systems is limited.
• Regular monitoring is required to ensure the filter remains effective.

Purpose: Construct a slow sand filter (SSF) for continuous water treatment.

Materials Required:
• Large box (at least 1.5 meters high)
• Gravel
• Clean, uniform sand with the following specifications:
- Effective size: between 0.15 and 0.35 mm
- Uniformity coefficient: less than 3
- Maximum size: 3 mm
- Minimum size: 0.1 mm
• Slotted pipe
• Geotextile layer (optional, for improved design)
• Ball valve from a toilet
• Elevated raw water tank or pump
• Chlorine or iodine (for chlorination)

Steps:
1. Ensure the SSF is used only for continuous water treatment. If a continuous supply of raw water cannot be guaranteed, use an alternative method.
2. Reduce turbidity in the raw water by using one of these methods:
- Build an infiltration gallery instead of taking water directly from a creek
- Use a raw water tank to allow suspended solids to settle out
- Pre-filter or flocculate (add alum to cause suspended material to clump together)
3. Construct the SSF box with rough walls to prevent water from bypassing the sand.
4. Place a gravel bed at the bottom of the filter, ensuring that the slotted pipe is placed within it for drainage. The slots or gravel should be no closer than 20 cm to the walls to avoid bypassing the sand.
5. Add clean and uniform sand with the specified size requirements to the SSF to a minimum depth of 0.6 meters. Additional thickness (e.g., 0.3 to 0.5 meters) will extend the filter's lifespan to 3-4 years.
6. Consider adding a geotextile layer on top of the sand to reduce cleaning frequency.
7. Ensure the outlet is positioned above the sand level but below the water level, and maintain a constant water level for even flow rate throughout the filter.
8. Use an elevated raw water tank or pump combined with a ball valve from a toilet to help regulate and maintain the water level.
9. Allow the SSF to stabilize for at least one week before drinking the filtered water, as it will take time for biological processes to establish themselves.
10. During stabilization, chlorinate the output (or use iodine) if possible to ensure safety from pathogens.
11. After stabilization, continue chlorinating the output periodically to prevent recontamination.

Cleaning and Maintenance:
• When the flow rate slows down, clean the filter by draining it and removing the top few inches of sand. If a geotextile layer is used, only remove the top ½ inch of sand.
• After refilling, allow a few days for biological processes to reestablish themselves before resuming normal use.

Important Notes:
• The SSF should not be used if a continuous water supply cannot be maintained.
• Ensure that the sand is clean and meets all size specifications for optimal performance.
• Chlorination or iodine treatment is recommended both during stabilization and after cleaning to prevent recontamination.

Procedure:

1. Select the type of activated charcoal:
- Use either purchased or homemade activated charcoal.
- Commercial products are preferred for consistent quality, but homemade charcoal can be used in a pinch.

2. Determine filter design:
- For simplicity and no pressure requirement, use the Water Washer ($59) from the Survival Center.
- Alternatively, construct your own filter using one of these methods:
- Granulated activated charcoal (GAC): Effective size should be between 0.6 to 0.9 mm for maximum flow rate.
- Compressed carbon block: Offers greater mass and longer lifespan but requires a source of pressure for adequate flow rate.
- Powdered activated charcoal (PAC): Can increase contact area; may be mixed with water and filtered out later if needed.

3. Ensure the filter has sufficient depth:
- The bed of carbon must be deep enough to allow adequate contact time between the water and the charcoal for effective adsorption.

4. Consider impregnation with silver (optional):
- Some commercial filters are impregnated with silver to prevent bacterial growth on the filter surface.
- Research suggests that bacteria growing on activated charcoal filters may be harmless, even if the water is not disinfected beforehand.

5. Recycle or rejuvenate the filter (if possible):
- Burn off adsorbed molecules by heating the charcoal to regenerate its filtering capacity.
- Note: This method will not remove heavy metals that have been adsorbed onto the charcoal.

6. Use in conjunction with chemical treatment (optional):
- Combine activated charcoal filters with chemical treatments like iodine or chlorine:
- The chemical will kill pathogens, while the carbon filter removes residual chemicals from the water.
- When the filter reaches its capacity, a distinctive taste of chlorine or iodine may be noticed in the filtered water.

To obtain British Berkefeld water filters, contact:

• Noah Water Systems, Inc.
- Address: 46373 Galway Dr., Novi, MI 48374
- Website: [www.noahwater.com](http://www.noahwater.com)
- Phone: 877-356-6624

• New Millennium Concepts, LTD.
- Address: P.O. Box 201411, Arlington, TX 76006
- Website: [www.bigberkey.com](http://www.bigberkey.com)
- Phone: 888-803-4438

Procedure for Filter Maintenance

• Disinfect the spout daily using soap and water or a chlorine cleaning solution.
• Wash the receiving container every second day with soap and water or a chlorine cleaning solution.
• Do NOT pour chlorine bleach into the top of the filter, as this can damage it.
• Clean the entire filter regularly, including the lid, diffuser, and outside surfaces.

Key Maintenance Requirements:
1. Disinfect the spout to prevent contamination from dirty hands, animals, or insects.
2. Clean the biolayer when the flow rate becomes insufficient.
3. Schedule follow-up visits as part of a hygiene education program to ensure proper use and maintenance.

Activated carbon (AC) filtration is most effective in removing organic contaminants from water. Organic substances are composed of two basic elements, carbon and hydrogen. Because organic chemicals are often responsible for taste, odor, and color problems, AC filtration can generally be used to improve aesthetically objectionable water. AC filtration will also remove chlorine.

AC filtration removes some organic chemicals that can be harmful if present in quantities above the EPA Health Advisory Level (HAL). These include:

1. Trihalomethanes (THM): A byproduct of the chlorination process used by most public drinking water systems for disinfection.
2. Pesticides
3. Industrial solvents (halogenated hydrocarbons)
4. Polychlorinated biphenyls (PCBs)
5. Polycyclic aromatic hydrocarbons (PAHs)

AC filtration is a viable alternative to protect private drinking water systems from organic chemical contamination. Radon gas can also be removed from water by AC filtration, but actual removal rates of radon for different types of AC filtration equipment have not been established.

Installation Steps:

1. Choose a safe location for the filter that is protected from sunlight, wind, rain, animals, and children.
2. Ensure the location is inside the home, preferably near the kitchen or food preparation area for convenience.
3. Verify that the location has level ground to prevent instability during installation and use.
4. Make sure there is adequate space around the filter for hauling pails of water, pouring them into the filter, and storing filtered water.
5. Avoid moving the filter once it is filled with media, as this can cause damage or injury.
6. Use proper lifting techniques when moving the filter (12” x 12” x 36”, weighing approximately 160 Lbs plus an additional 100 Lbs of media) to prevent injuries to the back, arms, and knees.
7. Be cautious of potential pinching or crushing hazards from fingers and toes under or behind the filter during installation.
8. Attach a maintenance guide (such as a laminated sheet) to the filter or place it on a wall near the filter for user reference.

### Tools Needed:
• Approximately 3 liters of washed ½” gravel
• Approximately 3 ¼ liters of washed ¼” gravel
• Approximately 25 liters of washed sand
• A stick (approximately 40” long, 1” x 2” is preferred)
• Measuring tape
• At least 2 buckets of water

### Steps:
1. Ensure the drain hole (the standpipe opening at the bottom inside of the filter) is clear and unobstructed. The flow rate through the copper pipe without any media in the filter should be 1 liter / 25 seconds.
- *Tip: This step should have been done when the filter was removed from the mold, however, double check now before you get too far into the installation.*

2. Ensure that the inside of the filter has been cleaned out (including dirt, dust, and oil from the mold).

3. Place a stick inside the filter so that it’s touching the bottom of the filter.

4. Draw a horizontal line on the stick where it meets the top edge of the filter.

5. Measure and mark a line 2” down from the first line.

6. Fill the filter half full of water. *The media must always be added with water already in the filter to prevent pockets of air from being trapped within the media.*

7. Add approximately 2” of under drain (½”) gravel to the filter.

8. Level out the gravel, and use the stick to measure how much has been added. Place the bottom of the stick on the gravel. When the second line on the stick lines up with the top edge of the filter, you have added enough gravel. *Ensure that the gravel covers the drain hole near the bottom of the filter.*

9. Measure and mark a line 2” down from the second line.

10. Add approximately 2” of support layer (¼”) gravel to the filter.

11. Level out the gravel, and use the stick to measure how much has been added. Again, place the bottom of the stick on the gravel. When the third line on the stick lines up with the top edge of the filter, you have added enough gravel.

12. Quickly pour approximately 20 liters of washed sand into the filter (ensuring that there is always water above the surface of the sand). *A random distribution of different sand grain sizes is critical to the proper operation of the filter. Adding the sand quickly maintains the random distribution by not allowing the different sizes of grains to settle into layers.*

13. Continue adding smaller quantities of sand until water starts to pour out of the spout. (Again, make sure that there is always water above the surface of the sand. Add water if necessary.) When the water stops pouring out of the spout, the water level is equalized. The water level in the filter is determined by the spout. Due to a siphoning effect, the water will stop coming out of the filter when the water is at the same level as the bottom of the spout.

14. Smooth out the sand and then measure the depth of the water above the sand bed.

15. If the water depth is less than 2”: remove sand until the depth is 2” (with the sand surface level and the water level equalized).

16. If the water depth is more than 2”: repeat steps 13 to 17 until the water depth is 2”.

17. Smooth out the surface of the sand so that it’s as level as possible.

Sediment filters should be installed ahead of AC filters to prolong their life:

1. Purchase a sediment filter that is compatible with your AC filtration system.
2. Install the sediment filter before the activated carbon (AC) filter in the water line.
3. Ensure the sediment filter is properly secured and connected to prevent bypassing.

Notes:
• Sediment filters are inexpensive compared to high-volume AC filters.
• They help prevent clogging of AC filters by removing particulate matter from the water.

Faucet-mounted activated carbon (AC) filters are compact units that attach to kitchen faucets:

1. Install the filter on the end of a standard kitchen faucet.
2. Turn on the water flow to allow filtered water to pass through the unit.
3. Use only for drinking and cooking if your unit has a bypass valve (some models allow you to separate filtered from unfiltered water).

Notes:
• These filters are convenient but require frequent replacement due to their small size.
• Some units have bypass valves, allowing for selective filtration of drinking and cooking water.

High-volume activated carbon (AC) filters are designed for large-scale water filtration:

1. Install the filter in-line, typically under a sink or at the point of entry to a home.
2. Connect it to the cold water line and ensure proper installation with a bypass valve if needed.
3. Use the bypass valve (if available) to separate filtered drinking/cooking water from other uses.

Notes:
• These filters are suitable for household or group use in emergency situations.
• Some units can be installed at the point of entry to treat all incoming water.

Procedure for Operating a Rapid Sand Filter:

1. Prepare Flocculent Solution:
- Mix flocculent (polymers) with water according to the manufacturer's specifications.
- Ensure the solution is evenly distributed and ready for injection into the filtration system.

2. Inject Flocculent:
- Continuously inject the flocculent solution into the influent stream at a precise rate determined by jar testing.
- Monitor the dosing to ensure it remains constant and effective.

3. Monitor Filter Performance:
- Track the filtration rate, which should be between 1 to 2 gallons per minute per square foot (gpm/ft²).
- Regularly check for signs of clogging or reduced efficiency.

4. Backwash the Filter Bed:
- When the filter becomes clogged or flow rates drop significantly, initiate a backwashing process.
- Reverse the flow through the filter bed at a high rate to fluidize the sand particles and flush out trapped material.
- Continue until the effluent is clear and free of debris.

5. Maintain Filter Bed:
- Ensure that the sand bed remains clean and functional after backwashing.
- Regularly inspect and replace any damaged or worn components.

6. Skilled Maintenance:
- A trained operator should oversee all operations to ensure proper function and efficiency of the rapid sand filter.

After pouring water into the BioSand filter, it is purified by the following four processes:

1. Mechanical trapping: Sediments, cysts and worms get trapped between the sand grains.
2. Adsorption or attachment: Viruses are adsorbed or become attached to the sand grains.
3. Predation: Microorganisms consume pathogens found in the water.
4. Natural death: Pathogens die because of food scarcity, short life span.

Steps to Prepare a Checklist:

1. Gather all necessary materials required for installation of the Bio-Sand filter.
2. Review the installation instructions thoroughly before beginning the process.
3. Include safety equipment such as gloves, eye protection, and any tools needed for setup.
4. Ensure that the location where the filter will be installed is already determined based on the guidelines provided.
5. Verify availability of water source and storage containers for filtered water.
6. Check the condition of the filter components to ensure they are undamaged.
7. Include a maintenance guide (such as a laminated sheet) in the checklist to be left with users after installation.

Procedure:

1. Pour the turbid water into a clean, covered container.
2. Allow the water to sit undisturbed for several hours or overnight.
3. Carefully pour off the clarified water from the top, leaving the settled particulates at the bottom of the container.

Notes:
• This is the simplest and cheapest method for pretreatment but may not be very effective in removing all suspended particles.
• It is best used as a preliminary step before other more advanced treatment methods.
• Ensure that the storage container is clean and sealed to prevent recontamination.

Problem: Traditional slow sand filters made of concrete are expensive and time-consuming to construct.

Solution:
1. Use molded polyethylene structures, which reduce engineering costs by amortizing them over multiple units produced.
2. Polyethylene filter vessels are cheaper to manufacture than concrete-based systems.
3. Ensure materials used in the polyethylene components are certified as non-toxic, eliminating the need for testing each installation.
4. Benefits include transportability, durability, and rapid setup (can be installed and started within hours).

Procedure:

1. Consider using activated carbon (AC) filters that have been impregnated with silver as a potential solution to bacterial growth.
2. These filters may offer some initial advantage in controlling bacteria during the first month of operation.
3. However, product testing has not shown significant long-term effectiveness compared to normal AC filters.
4. The EPA requires registration for all water treatment equipment that contains an active ingredient for inhibiting microbial growth.
5. Registration does not guarantee effectiveness but ensures that the active ingredient will not leach at harmful levels.

Important Notes:
• Silver impregnated AC filters are not significantly more effective than standard AC filters in long-term bacterial control.
• Regular flushing and monitoring of filter performance is still necessary, even with silver-impregnated units.

Gravity Driven Membrane (GDM) filtration removes all types of pathogens by ultrafiltration. Most ultrafiltration membranes have pores smaller than the size of bacteria and viruses. Water filtered through these membranes is microbiologically safe.

GDM filtration works with flux stabilisation. The pressure necessary to press water through the membranes is generated by gravity created by differences in water levels between two storage tanks. As a feed, natural water (river, spring, well or rainwater) can be used without pre- or posttreatment.

Neither pumps nor chemical cleaning or backflushing are necessary. Thus, no maintenance is required for long-term operation. A 40 – 60 cm water column is sufficient to operate the system using 0.5 m² of membrane to produce at least 50 litres of safe drinking water per day.

- Proven removal of protozoa and about 90 % bacteria
• One-time installation with few maintenance requirements
• Long life, durable and robust
• Easy to use
• Removes turbidity, some iron, manganese and arsenic
• Water quality improves with time
• Opportunity for local business

Procedure for Daily Use of a Water Filter

1. Educate all users, including children, on how the filter works, its purpose, and proper operation and maintenance.
2. Pour raw water into the filter daily, using at least 20 liters twice per day.
3. Use the same source of water every day to improve filter effectiveness.
4. Select the best available water source, as the quality of raw water directly affects treated water quality.
5. Pre-filter or settle raw water if it is not relatively clear (turbidity less than 50 NTU). To test turbidity:
- Fill a 2-liter clear plastic bottle with raw water.
- Place the bottle on large print, such as the CAWST logo in this manual.
- If you can see the logo, the turbidity is likely below 50 NTU.
6. Always use the diffuser when pouring water into the filter; never pour directly onto the sand layer.
7. Keep the lid on the filter at all times to prevent contamination.
8. Use a designated bucket for fetching raw water.
9. Store treated water in a designated safe container, which should have:
- A small opening to prevent recontamination from cups or hands.
- A tap or spigot for easy access.
10. Place the receiving container as close to the filter spout as possible (e.g., on a block) to reduce dripping noise and prevent recontamination.
11. Allow water to flow freely from the filter, never plug the spout or connect a hose, as this can damage the biolayer or cause siphoning.
12. Do not store food inside the filter. Food stored on the diffuser plate may be contaminated and attract insects.
13. Chlorinate treated water after it passes through the filter, using 1–5 drops per liter (or up to 1 teaspoon per gallon) to ensure quality and prevent recontamination.

Procedure:

1. Before using an activated carbon (AC) filter, run water through it for about 30 seconds.
2. This process helps flush out bacteria that may have built up in the filter over time.
3. The flushing procedure is most important when the filter has not been used for several hours, such as first thing in the morning.
4. Water filtered after this initial flushing will have much lower levels of bacteria.
5. This step helps avoid ingestion of a high concentration of non-pathogenic bacteria.

Important Notes:
• Flushing is especially important for individuals with weakened immune systems (e.g., young children, elderly, or those who are ill).
• Some types of non-pathogenic bacteria can cause illness in people with compromised natural defenses.

Maintenance and Accessibility Guidelines:

• Place the filter in a location that is easily accessible to users for regular use and maintenance.
• Ensure that users can reach the filter without difficulty, as this increases the likelihood of consistent use and proper maintenance.
• Avoid placing the filter in areas with high foot traffic or where it may be obstructed.
• Keep the area around the filter clean to prevent contamination from dirt, debris, or other environmental factors.
• Ensure that water can be easily poured into the top of the filter without difficulty.
• Provide clear instructions on how to use and maintain the filter to all users.

Objective: Use boiling to eliminate pathogens from contaminated water.

Procedure:
1. Collect the contaminated water in a clean container.
2. Pour the water into a pot or kettle, ensuring it is filled no more than three-quarters full to allow for expansion during boiling.
3. Place the pot on a heat source and bring the water to a rolling boil (bubbling vigorously).
4. Boil the water for at least 1 minute (or 3 minutes at high altitudes above 2,000 meters).
5. Allow the boiled water to cool down before consumption.
6. Store cooled water in clean, sealed containers and consume it within 24 hours.
7. If the water is still cloudy after boiling, repeat the process or use an alternative method of purification.

Objective: Use chlorine to kill pathogens in contaminated water.

Procedure:
1. Collect the contaminated water in a clean container.
2. Measure the volume of water to determine the correct amount of chlorine needed (typically 2 drops per liter for household use).
3. Add liquid chlorine or bleach to the water, ensuring it is well mixed.
4. Wait at least 30 minutes before consuming the water to allow the chlorine to work effectively.
5. Check the water for a faint chlorine smell, which indicates successful disinfection.
6. If no odor is present or if the water remains cloudy, repeat the process with additional chlorine or use an alternative method.
7. Store disinfected water in clean, sealed containers and consume it within 24 hours.

Chlorination is the most common method of disinfecting potable water. Sufficient chlorine is added to achieve the desired free available chlorine (FAC) residual after a 30-minute contact time.

Forms of Chlorine Available:
1. Calcium hypochlorite, 65-70% (HTH): Preferred agent due to its granular form, long shelf-life, and availability in various units including 100 lb drums, 3.75 lb containers, 6 oz bottles or 1 gm ampules.
2. Sodium hypochlorite (5%) or (10%): A liquid solution (household bleach) that may be used in lieu of HTH but is less convenient and has a shorter shelf-life than HTH.
3. Chlorine gas (in compressed gas cylinders): Most common form used by municipal systems.

Materials: 1 PET bottle, 0.5 litres of safe water, 1 cup

### Step-by-Step Procedure:

1. Wash the Bottle: Wash the bottle well with soap the first time you use it.
- Use appropriate bottles as described in exercise “Bottles for SODIS”.
- Clean both the bottle and lid thoroughly with soap.

2. Fill the Bottle: Fill the bottle with water and close the lid tightly.
- Perform a turbidity test using newspaper or fingers. If the water is cloudy, it needs to be pretreated.
- Do not fill the bottle to the top due to the expansion of warm water.

3. Expose to Sunlight: Place the bottles horizontally on a clean surface in direct sunlight where they will not be shaded.
- If possible, place them on a reflective surface like corrugated iron to enhance UV exposure.
- UV-A rays from the sun kill germs such as viruses, bacteria, and parasites.
- Rule of thumb for cloudy weather:
- If less than half of the sky is clouded over, six hours of sunlight will be sufficient to disinfect the water completely.
- If more than half of the sky is covered with clouds, the bottles must be placed in the sun for two consecutive days.
- The method does not work satisfactorily during days with continuous rainfall.

4. Consume or Store Safely: After exposure to sunlight, the water is ready for consumption.
- If stored, keep the bottle unopened and store it in a cool, dark place for several days.
- To prevent recontamination, drink directly from the bottle or pour into a clean cup or glass immediately before drinking.

### Advantages and Drawbacks:
• Advantages: Simple, low-cost, no chemical use, effective against most pathogens when used correctly.
• Drawbacks: Requires clear sunlight for at least six hours (or two days in cloudy weather), not suitable for highly turbid water without pre-treatment, limited to small quantities of water per bottle.

Procedure:

1. Determine the volume of water to be treated.
2. Calculate the required amount of chlorine based on the recommended dosage (typically 2 drops of liquid bleach per liter of water, or 1 tablet per liter for solid tablets).
3. Add the calculated amount of chlorine to the water and mix thoroughly.
4. Allow the water to sit for at least 30 minutes before consumption.

Notes:
• Chlorine is effective against most bacteria and viruses but may not eliminate all protozoa (e.g., Giardia or Cryptosporidium) without additional treatment.
• The effectiveness of chlorination can be reduced in highly turbid water; pretreatment with filtration or coagulation may be necessary.
• Always use the correct type and strength of chlorine product as recommended by health authorities.
• Chlorinated water should not be consumed immediately after treatment due to potential residual chemical taste.

Procedure:

1. Prepare the chlorine solution: Produce 0.5-litre of liquid chlorine solution in school.
2. Bring materials to class: Each child should bring chlorine products to the lesson for practical use.
3. Understand chlorination process: Learn about the steps involved in using liquid chlorine to treat water, including recognising when water is too turbid for effective treatment.
4. Practice chlorinating 20 litres of water: Use the prepared solution to treat a known volume of water under supervision.
5. Identify chlorinated water: Practice identifying chlorinated water in school settings for safe drinking purposes.

Procedure for Disinfecting Water with 10% Povidone-Iodine Solution:

1. Determine the desired concentration of iodine in the water:
- 4 ppm: Use 0.35 ml or 8 drops per liter or quart of water.
- 8 ppm: Use 0.70 ml or 16 drops per liter or quart of water.
2. Measure the required amount using a dropper (1 drop = 0.05 ml) or a tuberculin syringe.
3. Add the measured povidone-iodine solution to 1 liter or quart of water.
4. Allow the water to sit for at least 30 minutes before consumption.

Notes:
• Povidone-iodine solutions release free iodine, but data on their effectiveness is limited and should be used with caution.
• This method is suitable for emergency use only and not recommended for long-term water treatment.

Procedure for Disinfecting Water with 2% Iodine Tincture:

1. Determine the desired concentration of iodine in the water:
- 4 ppm: Use 0.2 ml or 5 drops per liter or quart of water.
- 8 ppm: Use 0.4 ml or 10 drops per liter or quart of water.
2. Measure the required amount using a dropper (1 drop = 0.05 ml) or a tuberculin syringe.
3. Add the measured iodine solution to 1 liter or quart of water.
4. Allow the water to sit for at least 30 minutes before consumption.

Notes:
• This method is suitable for short-term use and should not be used for long-term water treatment due to potential health risks from prolonged iodine exposure.
• Ensure that the solution is properly measured to avoid under or over-treatment.

Procedure for Disinfecting Water with 5% Household Bleach:

1. Determine the desired concentration of chlorine in the water:
- 5 ppm: Use 0.1 ml or 2 drops per liter or quart of water.
- 10 ppm: Use 0.2 ml or 4 drops per liter or quart of water.
2. Measure the required amount using a dropper (1 drop = 0.05 ml) or a tuberculin syringe.
3. Add the measured bleach to 1 liter or quart of water.
4. Allow the water to sit for at least 30 minutes before consumption.

Notes:
• This method is effective for short-term use and should not be used for long-term water treatment due to potential health risks from prolonged chlorine exposure.
• Ensure that the bleach is properly measured to avoid under or over-treatment.

Procedure for Disinfecting Water with AquaClear Tablets:

1. Use 1 tablet per liter or quart of water to achieve a concentration of 10 ppm.
2. Add the tablet directly to 1 liter or quart of water.
3. Allow the water to sit for at least 30 minutes before consumption.
4. If the water is cloudy or contains a high amount of organic matter, double the dose and wait 60 minutes.

Notes:
• AquaClear tablets are effective for short-term use but may not be suitable for long-term consumption due to potential health effects.
• This method is recommended for emergency situations when other disinfection methods are unavailable.

Procedure:

1. Prepare the bottles: Since warm water expands, do not fill the bottle to the top.
2. Position the bottles: Lay the bottles horizontally on a clean and unshaded surface in direct sunlight for at least six hours.
3. Use reflective surfaces if possible: Place the bottles on a reflective surface like corrugated iron to increase temperature and speed up disinfection, though this is not essential.
4. Avoid shaded or rainy conditions: The SODIS method is less effective during continuous rainfall or when more than half of the sky is clouded over. In such cases, the bottle must be placed in the sun for two consecutive days.
5. Check weather conditions: If less than half of the sky is clouded, six hours of exposure will suffice to completely disinfect the water.

Overview: The SODIS method uses sunlight to kill germs in water by exposing it to UV-A rays. Follow these steps for effective disinfection:

Steps:
1. Fill the bottle with clean water: Ensure the water is not contaminated with chemicals such as poisons, fertilizers, or industrial waste.
2. Close the lid securely: Make sure the bottle is tightly sealed to prevent contamination during exposure.
3. Place in full sunlight: Position the bottle in direct sunlight for at least six hours. UV-A rays will kill viruses, bacteria, and parasites in the water.
4. Check turbidity before use: Ensure the water is clear enough (less than 30 NTU) using either the newspaper or finger test. If it's too turbid, pretreat the water first.
5. Consume after exposure: After six hours of sunlight exposure, the water is disinfected and safe to drink.

Notes:
• The SODIS method does not change the chemical composition of the water. It only kills germs.
• This method has been used by over five million people worldwide for drinking water treatment.

Solar water disinfection (SODIS) is a method that uses sunlight to purify water. It involves filling transparent plastic bottles with water and exposing them to direct sunlight for several hours.

This lesson contains two parts: On the first day, children become familiar with the SODIS method and learn to apply it. On the second day, they can drink their own SODIS water.

Overview: The SODIS method uses transparent, colorless PET bottles to disinfect water using sunlight. Follow these steps to prepare the bottle:

Steps:
1. Select appropriate bottles: Use transparent and colorless PET bottles. These are ideal because they are lightweight, durable, and widely available. Look for the symbol ♻️ on the bottle.
2. Clean the bottle thoroughly: Wash the bottle well with soap to remove any dirt or contaminants.
3. Check for damage or scratches: Scratches on the surface of the bottle can reduce UV-A light penetration. Replace bottles that are heavily scratched (after about six months of daily use) or damaged.
4. Limit water volume: The bottle must not hold more than three litres, as UV radiation is reduced with increasing water depth.
5. Avoid using colored or opaque bottles: These do not allow sufficient UV-A light penetration for effective disinfection.
6. Do not reuse heavily used bottles: After about six months of daily use, replace the bottle to maintain effectiveness.

Overview: Before using the SODIS method, test the water turbidity to ensure it is suitable. Highly turbid water can reduce the effectiveness of UV-A light.

Steps:
1. Water turbidity test with newspaper:
- Place the filled bottle upright on top of a newspaper headline.
- Look down through the bottle opening. If the letters of the headline are readable, the water is suitable for SODIS. If not, pretreatment is required.
2. Water turbidity test with fingers:
- Place the filled bottle upright and put your hand behind the bottle.
- Look through the bottle and count the fingers. If you can see all the fingers clearly, the water is suitable for SODIS. If not, pretreatment is required.

Notes:
• The SODIS method works best with relatively clear water (less than 30 NTU).
• If the water is too turbid, it must be pretreated before using the SODIS method.

Advantages:

• Simple application: Easy to implement without specialized equipment.
• Low risk of recontamination: Water is served directly from treated bottles, reducing contamination risks.
• Proven effectiveness: Reduces bacteria and viruses effectively.
• Health benefits: Demonstrated positive health impact on communities using the method.
• No taste change: Does not alter the natural taste of water.
• Use of local resources: Relies on locally available materials like bottles and sunlight.
• Energy efficiency: Requires no electricity or fuel for operation.
• Low cost: Economical compared to other disinfection methods.

Drawbacks:

• Requires clear water: Turbid or cloudy water may not be effectively disinfected.
• Dependent on weather: Cloudy days or continuous rain reduce effectiveness and increase required treatment time.
• Long treatment times: May require several hours to two full days depending on conditions.
• Limited volume capacity: Treats only small volumes of water at a time.
• Requires clean bottles: Needs a large supply of intact, clean, and adequately sized bottles for effective use.
• No chemical changes: Does not remove chemical contaminants from the water.

Procedure:

1. When to treat water:
- Use this procedure only when you have no stored water and local authorities do not provide instructions.
- Contaminated water can cause diseases like dysentery, typhoid, and hepatitis due to microorganisms (germs, bacteria, viruses).

2. Preparation before treatment:
- Let suspended particles settle to the bottom or strain them through layers of paper towel or clean cloth.
- Always treat water for drinking, food preparation, or hygiene.

3. Treatment methods:
- Use a combination of methods (e.g., boiling + chlorination) as no single method is perfect.
- Boiling and chlorination kill microorganisms but do not remove heavy metals, salts, or other chemicals.

Overview: Chlorine bleach can be used to treat water, but it must be handled with care due to its corrosive nature.

Precautions:
• Protective Gear: Always wear gloves, a mask, and eye protection when handling bleach. This prevents contact with skin, eyes, or inhalation of fumes.
• Ventilation: Use bleach in a well-ventilated area to avoid inhaling toxic chlorine gas.
• Dilution: Use cold water for diluting bleach because hot water increases the release of chlorine fumes.

**Procedure For Bleach Exposure:
1. If bleach comes into contact with skin, rinse the affected area thoroughly with clean water for several minutes.
2. If bleach gets into the eyes, rinse the eye with clean water for an extended period (at least 15-30 minutes).
3. If bleach fumes are inhaled, use a salt and soda nasal wash (¼ tsp salt + ¼ tsp baking soda + 1 cup of water) to irrigate the nose and throat using an ear bulb syringe or by inhaling from a cupped palm.
4. For burns caused by chlorine gas exposure:
- Rest is essential for recovery.
- A steam tent may help soothe the respiratory tract.
- Cough medicine can be used to relieve discomfort.

Storage Of Bleach:
• Store bleach in opaque, sealed containers out of direct sunlight and away from heat sources.
• Do not open a new container until it is needed.
• Once mixed with water, the solution should only be prepared for use within the next week because it deteriorates quickly.

Procedure:

1. Purpose of settling:
- Removes most suspended particles from water.
- Extends the life of filters if used before filtering murky or muddy water.

2. Steps for settling:
- Fill a bucket or deep container three-quarters full with contaminated water.
- Dig pulverized clay or clayey soil from a depth of four or more inches below ground surface.
- Use about 1-inch depth of dry clay or clayey soil for every 4-inch depth of water.
- Stir the clay into the water until practically all particles are suspended.

3. Settling and siphoning:
- Let the clay settle for at least 6 hours.
- Carefully dip out or siphon the clear water from the top.
- Disinfect the settled water before use.

Procedure:

1. Purpose of straining:
- Removes larger particles like dirt and may remove certain tiny organisms (e.g., copepods) that carry pathogens.
- Improves the effectiveness of other treatment methods.

2. Straining process:
- Use a clean handkerchief or fine, cotton cloth to strain turbid water.
- This is especially useful in areas where such organisms are present.

Procedure:

1. Determine the volume of water to be chlorinated (in gallons).
2. Decide on the desired chlorine concentration (mg/L) based on water quality and usage.
3. Locate the row in Table I-2 that matches the volume of water you are treating.
4. Find the column corresponding to your chosen chlorine concentration (e.g., 1 mg/L, 5 mg/L, etc.).
5. Use the value at the intersection as the amount of 70% available chlorine HTH required.

Example:
• If you need to treat 25 gallons of water with a 5 mg/L chlorine concentration: Look at the 25 gallons row and find the 5 mg/L column. The value is 20.7 mL, so use 20.7 mL of 70% available chlorine HTH.

Notes:
• This table assumes you are using 70% available chlorine HTH (not diluted solutions).
• Always ensure proper mixing and allow sufficient contact time for chlorine to work effectively.

After the water is analyzed, you can use the following chart to determine what treatment methods are needed to correct the problem. You may have identified more than one problem. If this is the case, you may need more than one type of treatment. Many reputable water treatment companies have equipment that will treat more than one problem.

Procedure:

1. Identify the unit you want to convert from and the unit you want to convert to.
2. Locate the row corresponding to the unit you are converting from (e.g., ounce, mL, tsp, etc.).
3. Find the column corresponding to the unit you are converting to (e.g., drop, mL, tsp, etc.).
4. Use the value at the intersection of that row and column as the conversion factor.
5. Multiply or divide accordingly based on whether you're moving left/right or up/down in the table.

Example:
• To convert 1 ounce to cups: Look at the ounce row, find the cup column. The value is 0.125, so 1 oz = 0.125 cups.
• To convert 3 mL to drops: Look at the mL row, find the drop column. The value is 15, so 3 mL = 45 drops (3 × 15).

Notes:
• All values on the same horizontal line are equal.
• Values moving down a single column indicate how many of the units at the top make up one of the units to the left.

Procedure:

1. Identify the fraction you want to convert to a decimal.
2. Locate the row in Table I-4 that corresponds to your fraction.
3. Find the value in the Decimal column for that fraction.
4. Use this decimal equivalent for calculations or measurements requiring decimals.

Example:
• To convert 3/8 to a decimal: Look at the row for 3/8, find the 0.375 in the Decimal column. So, 3/8 = 0.375.
• To convert 11/16 to a decimal: Look at the row for 11/16, find the 0.6875 in the Decimal column. So, 11/16 = 0.6875.

Notes:
• This table is useful for precise measurements and calculations involving fractions and decimals.
• It can be used in conjunction with other tables (e.g., Table I-3) to convert between units or perform complex conversions.

Overview:
For drilled wells where traditional bucket methods are not feasible, a homemade water retrieval device can be constructed using galvanized pipe and flapper valves.

Procedure:
1. Take a 2-foot length of galvanized pipe and attach end caps to both ends that fit the well casing.
2. Drill a small hole in the upper cap for a screw eye and another small hole for ventilation.
3. On the lower end, drill a hole about half the diameter of the pipe and insert a piece of rigid plastic or rubber as a flapper valve (this allows water to enter but not exit).
4. Lower the assembly into the well casing using the screw eye for attachment.
5. The weight of the pipe will cause it to fill with water, which can then be lifted to the surface by pulling on the screw eye.
6. Ensure the upper cap is in place to prevent the pipe from catching during retrieval.

Notes:
• This method is useful for retrieving water from drilled wells where traditional methods may not work.
• The flapper valve ensures that once filled, the device holds water until it reaches the surface.

Overview:
This method involves placing the pump cylinder inside the well and using a power source (such as windmills or hand pumps) above ground. It is suitable for both shallow and deep wells.

Procedure:
1. Install the pump cylinder inside the well casing, ensuring it is properly secured.
2. Connect the pump to an external power source such as a windmill, hand pump, or other mechanical system located above ground.
3. For shallow wells, some hand pumps use suction lines and aboveground pumps for water retrieval.
4. Test the system for proper operation and ensure that the pump can lift water from the well to the surface.

Notes:
• This method is commonly used in rural or off-grid settings where mechanical power sources are available.
• Hand pumps may require manual effort, so they are best suited for low-flow applications.

Overview:
For wells deeper than 20 feet, submersible pumps are commonly used and can operate at depths up to 1000 feet.

Procedure:
1. Ensure the well is deep enough (minimum depth of 20 feet).
2. Install a submersible pump directly into the well casing, ensuring it is fully submerged in water.
3. Connect the pump to an electrical power source above ground if necessary.
4. Test the system for proper operation and water flow.

Notes:
• Submersible pumps are ideal for deep wells due to their ability to operate at great depths without relying on suction.
• Ensure the pump is compatible with the well's depth and water conditions.

Overview:
For wells up to 350 feet, a surface pump with an ejector system can be used. This method uses two pipes: one carrying water down, and the other returning it.

Procedure:
1. Install two pipes inside the well casing: one for water delivery and one for return flow.
2. Attach an ejector at the bottom of the pipes to create a jet effect that lifts water up the well with the returning pumped water.
3. Ensure an efficient foot valve is installed, as these pumps cannot self-prime.
4. If using the annular space between one pipe and the casing as the second pipe, install a packer (seal) at both the ejector and the top of the casing to prevent leakage.
5. Test the system for proper water flow and pump operation.

Notes:
• This method is suitable for shallow to medium depth wells but requires careful installation of the foot valve and ejector.
• Regular maintenance of the foot valve is essential to ensure continued functionality.

Overview:
In addition to modern pump systems, several primitive but effective methods exist for lifting water from wells.

Procedure:
1. Bucket and Rope Method: Lower a bucket on a rope into the well and pull it up manually. This is suitable only for large, shallow wells or wells with accessible openings.
2. Chain Bucket System: Use a chain with multiple buckets attached to lift water in segments. This method requires careful setup but can be effective for small-scale use.
3. Rope and Pipe System: Use a continuous loop of rope that drops into the well and returns up a small-diameter pipe. Sealing washers along the rope ensure water is pulled up with the rope.
4. Ancient Chinese Knot Method (Historical): Uses knots to lift water, but modern designs use rubber washers made from tires, which are more durable and suitable for deeper wells.

Notes:
• These methods are ideal for off-grid or emergency situations where modern pumps may not be available.
• Rubber washer systems are preferred over historical knot-based methods due to their reliability and depth capability.

Overview:
Water can only be moved by suction for an equivalent head of about 20 feet. Beyond this depth, cavitation occurs, which causes water to boil off in tiny bubbles due to the vacuum created by the pump rather than being lifted. This results in either no water being pumped or potential damage to the pump.

Key Considerations:
• Cavitation can destroy pumps if not addressed.
• Water movement beyond 20 feet requires alternative pumping methods.
• Proper pump selection is critical for wells deeper than 20 feet.

Overview:
Some water treatment methods may be ineffective or dangerous, especially in emergency situations. It is crucial to identify these methods and avoid relying on them for safe drinking water.

Steps to Identify Questionable Methods:
1. Research the product’s claims:
- Be cautious of products that make broad or unverified claims about eliminating all types of contaminants (e.g., bacteria, protozoa, chemicals, heavy metals).
2. Check for independent testing data:
- Verify if there are peer-reviewed studies or independent laboratory results confirming the product’s effectiveness.
3. Review manufacturer transparency:
- If a company refuses to release detailed information about its disinfectant or does not provide concentration-time data, this is a red flag.
4. Evaluate compliance with scientific principles:
- Be wary of products that claim to use technologies that violate known laws of physics or chemistry (e.g., filters that supposedly remove heavy metals without proper filtration media).
5. Check for regulatory approval:
- While meeting EPA or FDA specifications may be a positive sign, it is not a guarantee of effectiveness in real-world scenarios.

Examples of Questionable Methods:
• Aerobic 07 (also sold as Aerobic Oxygen):
- The company does not release information about the disinfectant used. It may contain chlorine dioxide, which is unstable and has limited data on its effectiveness against Giardia.
- No independent testing or concentration-time data is available for this product.
• Survival Straw:
- Claims to remove bacteria, protozoa, fungi, chemicals, and heavy metals using a metal alloy matrix.
- The manufacturer’s claims about meeting EPA and FDA specs do not confirm the filter's real-world effectiveness.
- This product violates known laws of physics, which raises concerns about its reliability.

Action to Take:
• Do not rely on these products for long-term or life-critical water treatment in survival situations.
• Use proven methods such as boiling, chemical purification (e.g., iodine tablets), or filters with verified specifications and independent testing data.

Overview:
RO systems can reduce nitrate levels in water, but the required rejection rate depends on the initial concentration of nitrates.

Procedure:
1. Determine the initial nitrate-nitrogen (NO3-N) level in the water supply. This is typically measured in milligrams per liter (mg/l).
2. Calculate the desired final nitrate level. Ensure that it meets health standards, which are generally below 10 mg/l.
3. Use the formula: Rejection rate = (Initial concentration - Final concentration) / Initial concentration.
4. Example calculation: If the initial nitrate level is 20 mg/l and a final level of 3 mg/l is desired:
- Rejection rate = (20 - 3) / 20 = 17 / 20 = 0.85 or 85%.
5. Consider high nitrate levels: If the initial nitrate level exceeds 40 mg/l, special RO system designs are required as per NSF guidelines.

Overview:
RO systems require ongoing maintenance to ensure continued effectiveness and longevity.

Procedure:
1. Consider electricity costs. The only significant operating cost is the electricity required to pump water through the system.
2. Plan for filter replacement. Both pre- and post-filters need regular cleaning or replacement, depending on usage and contaminant levels.
3. Schedule membrane replacements. RO membranes should be replaced periodically based on manufacturer recommendations and performance monitoring.
4. Monitor system performance:
- Regularly check the system's output and waste water volume to ensure it is functioning properly.
- Keep track of maintenance costs over time for budgeting purposes.
5. Factor in long-term expenses when comparing different RO systems or other water treatment options.

Overview:
RO systems are highly inefficient in terms of water usage, as they waste a significant amount of water during the treatment process.

Procedure:
1. Determine the daily output of treated water. For example, an RO unit may deliver 5 gallons of treated water per day.
2. Calculate the waste water volume. RO systems typically recover only 5 to 15% of the water entering the system, with the remainder discharged as wastewater.
3. Use the formula: Waste water = Treated water / Recovery rate - Treated water.
4. Example calculation: If an RO unit delivers 5 gallons per day and has a recovery rate of 10%:
- Waste water = (5 / 0.10) - 5 = 50 - 5 = 45 gallons per day.
5. Consider the impact on septic systems: The wastewater from RO units is typically connected to house drains and can increase the load on household septic systems.

Overview:
Reverse osmosis (RO) is a method for treating household drinking and cooking water supplies, but it has limitations. It should not be used where large volumes of water are being treated or in cases of coliform bacteria contamination.

Procedure:
1. Assess the purpose of the RO system. Ensure that it is only used for treating drinking and cooking water, as it is not suitable for larger water supplies.
2. Check for bacterial contamination. Do not use an RO system if the water supply is contaminated by coliform bacteria.
3. Consider multiple contaminants. If the water contains more than one contaminant, note that the rejection rate may be reduced or one contaminant may be prioritized over another during treatment.
4. Evaluate initial contamination levels. The effectiveness of RO systems depends on the initial concentration of contaminants and water pressure.
5. Consult guidelines for high nitrate levels. If nitrate-nitrogen (NO3-N) levels exceed 40 mg/l, use special designs as recommended by the National Sanitation Foundation (NSF).

Overview:
RO systems vary in cost, quality, and effectiveness. It is important to select a system that meets your specific water treatment needs.

Procedure:
1. Test the water supply. Before purchasing any water treatment equipment, test the water to determine if treatment is needed and which contaminants are present.
2. Choose an appropriate RO unit. Ensure that the system is suitable for treating drinking and cooking water only, not large volumes or contaminated with coliform bacteria.
3. Consider initial costs:
- RO units range in cost from $300 to $3000.
- Replacement membranes cost between $100 to $200.
- Filter cartridges typically cost around $50.
4. Ensure all parts are included when comparing different systems for purchase or rental.
5. Consider installation costs:
- These are generally the responsibility of the purchaser, unless renting or leasing.
- Ensure that there is enough space to accommodate the system and consider any necessary modifications.

To prevent water recontamination during storage, follow these steps:

1. Use clean containers: Ensure that all containers used for storing water are thoroughly cleaned and disinfected before use.
2. Cover containers tightly: Always cover water containers to prevent dust, insects, and animals from contaminating the water.
3. Store in a cool, dry place: Keep water storage containers away from direct sunlight and sources of heat or moisture.
4. Avoid contact with contaminants: Ensure that no dirty objects, hands, or surfaces come into contact with the container opening.
5. Keep containers out of reach of animals: Store water in locations where it is inaccessible to animals.
6. Monitor storage conditions regularly: Check on stored water periodically to ensure that it remains uncontaminated and safe for use.

Objective: Identify improper water storage methods that can lead to contamination.

Procedure:
1. Inspect containers for damage, such as cracks or leaks.
2. Check for cleanliness of the container before and after filling with water.
3. Ensure lids are tightly sealed to prevent insects, animals, and contaminants from entering.
4. Store containers in a cool, dry place, away from direct sunlight and sources of pollution (e.g., animal waste).
5. Avoid storing water near chemicals or garbage that could leach into the water.
6. Monitor stored water regularly for signs of contamination (e.g., cloudiness, bad odor, visible debris).

Title: Acquire and Store Water Buckets for Emergency Use

Procedure:
1. Purchase two 5-gallon water buckets.
2. Ensure the quantity is sufficient for at least 30 days of use.
3. Store them in a dry, accessible location.
4. Use the water buckets to store and transport water during emergencies when regular sources may be unavailable.

Notes:
• Water buckets are essential for storing and transporting water in survival situations.
• Ensure that they are stored safely and are ready for use at any time.

Procedure:

1. Store treated water properly: After treatment, keep the bottle unopened and store it in a cool, dark place for several days.
2. Consume immediately or safely: The treated water should be drunk directly from the bottle or poured into a clean cup or glass immediately before consumption to avoid recontamination.

Procedure:

1. Select a fixed, clean, and elevated place for the safe water station.
2. Prepare a table or board to serve as a base for storing vessels or bottles of water.
3. Include cups or glasses for drinking water at the station.
4. If available, add a closet or storage compartment to keep cups and glasses clean and organized.

Overview:
Proper storage of distilled water is crucial to maintain its purity and prevent contamination from bacteria or other impurities.

Steps for Safe Storage:
1. Use appropriate containers: Store distilled water in plastic, glass, or stainless steel containers that are free from cracks, leaks, or chemical residues.
2. Ensure the container is clean and sanitized before filling it with distilled water. This can be done using a mild soap solution or by boiling the container for 10 minutes.
3. Avoid exposure to sunlight: Store distilled water in a cool, dark place to prevent degradation of the water quality due to UV light exposure.
4. Seal the container tightly after filling it with distilled water to prevent contamination from dust, bacteria, or other airborne particles.
5. Label the container clearly, indicating the date the water was distilled and stored. This helps track its shelf life and ensures that older batches are used first.
6. Monitor storage conditions: Ensure that the storage area is free from strong odors, chemicals, or other contaminants that could leach into the water over time.
7. Check periodically for signs of contamination, such as cloudiness, unusual odors, or visible particles in the water.

Notes:
• Distilled water should be used within a reasonable timeframe (e.g., 6 months) to avoid bacterial re-colonization on storage containers or cooling coils.
• If distilled water is stored for extended periods, it may become slightly acidic due to carbon dioxide absorption from the air. This can be mitigated by storing it in sealed containers and using it within a short timeframe.

Procedure:

1. Choose the right location: Dig in depressions, valleys, or areas with green plants and signs of dampness.
2. Dig a hole: Create a hole large enough to accommodate a container at its center.
3. Place a container inside: Use a clean, sealed container to collect condensed water.
4. Cover the hole with a clear plastic sheet: Ensure it is taut and covers the entire opening of the hole.
5. Add weight to the center: Place a stone in the middle of the plastic sheet to create a dome shape, which helps direct condensation into the container.
6. Secure the edges: Weight down the edges of the plastic sheet with stones or other heavy objects to prevent it from lifting due to wind.
7. Place in sunny areas: Position the still in a location that receives maximum sunlight to increase evaporation and condensation rates.
8. Enhance water production: Add succulent leaves or vegetable matter into the hole to provide more moisture for evaporation.
9. Use a flexible hose (optional): If needed, use a flexible hose to suction water from the container when it accumulates.

Surface water often requires treatment but can be made safer through proper collection methods.

### Steps:
1. Choose fast-flowing creeks or rivers that are not near large sources of pollution in their watershed.
2. Use an infiltration gallery or well to collect small amounts of water needed by a family or small group.
3. These methods reduce turbidity, making the water easier to treat later.
4. Avoid collecting water from stagnant pools, lakes, or slow-moving streams unless absolutely necessary and only after thorough treatment.

Procedure:

1. Select a suitable branch: Choose a healthy plant or tree branch that is not poisonous.
2. Place a transparent bag over the branch: Use a clear garbage bag or similar transparent material.
3. Seal the bag airtight: Ensure no air can escape from the bag to maximize condensation.
4. Collect condensed water: Water will condense and collect at the corner of the bag. Make a small hole or slit in the bag to drain the collected water.
5. Re-seal the bag: After draining, tie or seal the bag shut again to continue collection.
6. Avoid overuse: Do not leave the bag on the branch for too long, especially in hot weather, as it may harm or kill the plant.
7. Use only non-toxic plants: Never use poisonous plants for this method.

Procedure:

1. Choose the right roofing material: Use smooth, dense, and non-toxic materials such as corrugated aluminum, galvanized iron, concrete, asphalt or fiberglass shingles, tiles with a neoprene-based coating, or mud.
2. Avoid natural materials: Do not use thatch or similar organic materials for drinking water collection, as they may attract insects and rodents and yield contaminated water.
3. Use flat ground surfaces carefully: If using flat areas like runways, ensure they are fenced off to prevent contamination from animals and humans.
4. Discard initial runoff: Allow the first runoff after a long dry spell to flow away; this helps clean dust and debris from the roof or catchment area.
5. Calculate water yield: One millimeter of rainfall yields about 0.8 liters per square meter (or 6.4 gallons per square yard in US units). In cooler climates, you may get closer to a full liter per square meter.
6. Cover storage containers: Always cover water storage containers to prevent contamination from dust and debris.
7. Screen openings: Ensure all pipes or tank openings (except the faucet) are screened to prevent mosquito breeding and insect access.
8. Use appropriate collection methods: Refer to illustrations for examples of rainwater catchment options.

Purpose: To collect water from vegetation using a solar still.

### Materials Required:
• Clear plastic bag (preferably a 1-gallon zip-lock bag)
• Green leafy vegetation (avoid poisonous plants)
• Small rock or similar item
• Tubing, straw, or hollow reed (optional but recommended)
• Sunny slope

### Steps:
1. Select a location: Choose a sunny slope for placing the still.
2. Fill the bag with air: Turn the opening of the bag into the breeze or "scoop" air into it.
3. Add vegetation: Fill the bag half to three-quarters full with green leafy vegetation. Ensure no hard sticks or sharp spines are present that could puncture the bag.
4. Insert a rock: Place a small rock in the bag to help collect condensation at the bottom.
5. Secure the bag: Close the bag and tie the mouth securely as close to the end of the bag as possible, leaving maximum air space inside.
6. Add tubing (optional): If available, insert one end of a small piece of tubing, straw, or hollow reed into the mouth of the bag before tying it. Tie off or plug the tubing so that air will not escape. This allows you to drain condensed water without untying the bag.
7. Position the still: Place the bag on a slope in full sunlight with the mouth slightly higher than the low point in the bag. Ensure the rock settles into the lowest part of the bag.
8. Collect water: To retrieve water, loosen the tie and tip the bag so that collected water drains out. Retie the mouth and reposition the still to allow further condensation.
9. Replace vegetation: After extracting most of the water from the current vegetation, replace it with fresh green leafy material.

### Notes:
• Solar stills are not sufficient for meeting daily water requirements but can supplement reserves.
• Avoid using poisonous plants as they will produce toxic liquid.
• Using a 1-gallon zip-lock bag is more efficient than other types of bags.

Using aluminum sulfate (alum) as a pretreatment can help coagulate suspended particles in water, making them easier to remove through filtration.

Steps:
1. Determine the volume of water that needs treatment.
2. Calculate the required amount of alum, typically 5-10 grams per liter of water for standard use.
3. Add the calculated amount of alum to the water, ensuring it is evenly distributed.
4. Stir the water vigorously for several minutes to encourage coagulation of suspended particles.
5. Allow the water to sit undisturbed for 1-2 hours to allow flocs (coagulated particles) to settle at the bottom.
6. Carefully pour off the clear water from the top layer, avoiding disturbing the settled flocs.

Notes:
• Alum is effective in reducing turbidity and improving filtration efficiency.
• It should be used with caution, as excessive use can lead to increased levels of aluminum in the water.

Procedure for Chemical Water Treatment Using Bleaching Powder (Chlorinated Lime):

1. Determine the amount of water to be treated.
2. Use bleaching powder, which contains 33-37% chlorine when produced.
3. Add the appropriate amount of bleaching powder based on the volume of water and desired chlorine concentration (typically around 2-4 PPM for basic disinfection).
4. Mix thoroughly and wait for the recommended time before consuming the water.

Important Considerations:
• Bleaching powder loses its effectiveness rapidly when exposed to air, light, or moisture.
• It is not as stable or long-lasting as other chlorine-based treatments like AquaCure or Halazone tablets.
• Unless free chlorine is measured, disinfection cannot be guaranteed with moderate doses of chlorine.
• Chlorine will not kill Cryptosporidia.

Procedure for Chemical Water Treatment Using Chlorine Tablets:

1. Determine the amount of water to be treated.
2. Use 2 Halazone tablets per liter of water.
3. Wait for the recommended time (as specified by manufacturer or source material) before consuming the water.
4. Note: Halazone tablets have a nominal shelf life of 6 months and are not currently available in the US.

Important Considerations:
• Chlorine reacts with organic materials, reducing its effectiveness as a disinfectant.
• Trihalomethanes (carcinogenic byproducts) may form during treatment. These can be filtered out using activated charcoal.
• Unless free chlorine is measured, disinfection cannot be guaranteed with moderate doses of chlorine.
• Chlorine is sensitive to pH and temperature: effectiveness drops when pH exceeds 8.
• Chlorine will not kill Cryptosporidia.

Using bleach to clean contaminated surfaces and objects is an effective method of disinfection.

Steps:
1. Prepare a solution of 1 part household bleach to 9 parts water, creating a 10% dilution.
2. Apply the solution to the surface or object using a cloth, sponge, or spray bottle.
3. Allow the solution to sit for at least 10 minutes to ensure complete disinfection.
4. Rinse the surface or object with clean water and allow it to air dry.

Notes:
• Bleach is effective against a wide range of pathogens, including bacteria, viruses, and fungi.
• It should be used in well-ventilated areas and handled with care to avoid skin contact or inhalation.

Using iodine to disinfect water is a portable and effective method when other purification methods are not available.

Steps:
1. Determine the volume of water that needs treatment.
2. Calculate the required amount of iodine, typically 5 drops per liter of water for standard use, or more if the water is heavily contaminated.
3. Add the calculated amount of iodine to the water, ensuring it is evenly distributed.
4. Allow the water to sit for at least 30 minutes before consumption, or longer if necessary to ensure complete disinfection.

Notes:
• Iodine is effective against bacteria and viruses but may not be as effective against certain protozoa like Giardia.
• It should be used with caution in individuals with thyroid conditions or pregnant women.

Kahn-Vassher solution:

To prepare a saturated iodine solution:
1. Add sufficient amount of iodine crystals to a small bottle until the solution is saturated.
2. As long as crystals remain in the bottle, the solution remains saturated.
3. Use commercial models such as Polar Pure, which incorporate a liquid crystal thermometer to determine dose.

Usage with Polar Pure Bottle:
1. At 68° F, pour off 15 cc of supernate into a liter of water to yield a dose of 9 mg/l.
2. For microfiltered water requiring a 0.5 PPM concentration, use either large batches (e.g., 1/2 oz to 4.5 gallons) or measure with a TB syringe or medicine dropper.
3. A USP medicine dropper should give 20 drops per ml.

Warning: Ensure the solution is kept in glass bottles and avoid freezing, though it doesn’t affect the crystals.

Tincture of Iodine: USP tincture of iodine contains 2% iodine and 2.4% sodium iodide dissolved in 50% ethyl alcohol. For water purification use, the sodium iodide has no purification effect, but contributes to the total iodine dose. Thus it is not a preferred source of iodine, but can be used if other sources are not available.

To prepare an 8 mg/l (same as 8 PPM) solution:
1. Add 0.4 cc’s (or 8 drops) of USP tincture (2% iodine) to a liter of water.
2. If the iodine tincture isn’t compounded to USP specs, calculate an equal dose based on the iodine concentration.

Warning: Sodium iodide has no purification effect but contributes to total iodine dose.

Betadyne (povidone iodine):

Some have recommended 8 drops of 10% povidone iodine per liter of water as a water treatment method. At low concentrations, it can be regarded as a solution of iodine.

• One study indicated that at 1:10,000 dilution (2 drops/liter) there was 2 PPM iodine, while another study resulted in conflicting results.
• However, at 8 drops/liter, there is little doubt that there is an antimicrobial effect.

Note: The manufacturer hasn’t tested this product against EPA standard tests, but it has been sold for use in field water treatment in other countries.

Warning: Use with caution due to lack of standardized testing and potential variability in effectiveness.

Iodine Resin Filter:

• Some commercial microfilters incorporate an iodine resin stage to kill viruses and bacteria without adding as much iodine in the water.
• A few products rely exclusively on an iodine resin stage.

Advantages:
• Produces less iodine in the water for the same antimicrobial effect, as resins only release iodine when contacted by a microbe.

Disadvantages:
• Fragile nature.
• Dependency of effectiveness on flow rate.
• Inability to identify when they need to be discarded.

Recommendation:
• Use brands such as PUR or Sweetwater Viraguard if the water is known to be contaminated with viruses.
• In cold weather, more than one pass through the filter may be necessary.

Tetraglycine hydroperiodide (e.g. Potable Aqua):

• This is the form of iodine used by the US military for field treatment of water in canteen-sized batches.
• Usual dose: 1 tablet per quart of water to give a concentration of 8 mg/l.
• For cloudy or cold water, use 2 tablets per quart, or double the contact time.

Warning:
• The product loses iodine rapidly when exposed to air. According to the manufacturer, it has near-indefinite life when sealed in the original bottle but should be discarded within a few months of opening.
• Tablets change color from gun metal gray to brown as they lose iodine. A brown tint to the water after treatment indicates that the tablet is still effective.

Boiling water is one of the most effective methods to purify it. Follow these steps:

1. Fill a container with water that needs purification.
2. Place the container over a heat source, such as a fire or stove.
3. Bring the water to a rolling boil (a vigorous, continuous boil).
4. Boil for at least 1 minute at sea level. If you are at higher altitudes (above 5,000 feet), boil for 3 minutes to ensure all pathogens are destroyed.

Notes:
• Boiling water removes bacteria, viruses, and parasites.
• It does not remove chemical contaminants like heavy metals or pesticides.
• Always allow the boiled water to cool before drinking.

Expedient filtering can be used in emergencies to remove contaminants from water when proper filtration systems are not available.

Steps:
1. Gather materials: A plastic bottle, activated charcoal (if available), sand, gravel, and cloth or filter paper.
2. Cut the bottom off the plastic bottle and invert it so that the neck is at the bottom.
3. Insert a layer of coarse gravel into the bottle to form the base.
4. Add a layer of fine sand on top of the gravel.
5. Place activated charcoal (if available) over the sand layer.
6. Cover the top with a clean cloth or filter paper to prevent particulate matter from passing through.
7. Pour water into the bottle, allowing it to pass through all layers and collect in the bottom container.

Notes:
• This method removes larger particles, sediment, and some contaminants but may not eliminate all bacteria or viruses.
• It should be used as a preliminary step before boiling or chemical treatment.

Settling water allows suspended particles to settle at the bottom of a container over time.

Steps:
1. Pour the water into a clean, wide-mouthed container that is free from contaminants.
2. Allow the water to sit undisturbed for several hours, ideally overnight.
3. Carefully pour off the clear water from the top layer, avoiding disturbing the sediment at the bottom.
4. If necessary, repeat the process with fresh containers until the water is sufficiently clear.

Notes:
• Settling removes larger particulate matter but does not eliminate bacteria or viruses.
• This method should be used in conjunction with other purification methods for safe drinking water.

Straining water is a preliminary step in physical treatment to remove large particles and debris.

Steps:
1. Use a clean cloth, filter paper, or fine mesh as a strainer.
2. Pour the water through the strainer into another container.
3. Inspect the strained water for any remaining visible particulate matter.
4. If necessary, repeat the process with fresh straining material until the water is clear of large debris.

Notes:
• Straining does not remove microscopic contaminants like bacteria or viruses.
• It should be used in conjunction with other methods such as boiling or chemical treatment for complete purification.

Microfilters are portable devices that remove bacteria and protozoa from water but do not eliminate viruses.

Steps:
1. Select a microfilter with a pore size of 0.2 microns or smaller to ensure effective removal of bacteria and protozoa.
2. Follow the manufacturer's instructions for assembly, ensuring that all components are properly connected.
3. Pour water into the filter, allowing it to pass through the filtration media and collect in a clean container.
4. Inspect the filtered water for clarity and ensure there is no visible particulate matter remaining.

Notes:
• Microfilters should not be used as the sole method of purification if viruses are suspected.
• They require regular cleaning and maintenance to remain effective.

Procedure:

1. Calculate the Battalion Factor by adding the following values:
- Unit Factor: 11.2 gallons per man per day
- Heat Treatment: 1.0 gallon per man per day
Total Battalion Factor = 12.2 G/M/D

2. Multiply the Battalion Factor (12.2) by the number of personnel in the battalion (750 men) to get the Battalion Consumption:
- 12.2 x 750 = 9150 gallons per day

3. Add a 10% waste factor to account for spillage and inefficiencies:
- 9150 + (9150 x 0.1) = 9150 + 915 = 10,065 gallons per day

Result: The battalion requires 10,065 gallons of water per day.

Procedure:

1. Calculate the Brigade Factor by adding the following values:
- Battalion Factor: 12.2 gallons per man per day
- Central Hygiene: 1.3 gallons per man per day
Total Brigade Factor = 13.5 G/M/D

2. Multiply the Brigade Factor (13.5) by the number of personnel in the brigade (3500 men) to get the Brigade Consumption:
- 13.5 x 3500 = 47,250 gallons per day

3. Add a 10% waste factor to account for spillage and inefficiencies:
- 47,250 + (47,250 x 0.1) = 47,250 + 4725 = 51,975 gallons per day

Result: The brigade requires 51,975 gallons of water per day.

Procedure:

1. Calculate the Division Factor by adding the following values:
- Brigade Factor: 13.5 gallons per man per day
- Hospital Use: 1.0 gallon per man per day
- Laundry: 2.0 gallons per man per day
- Gravely (unknown context, assumed to be a specific use): 0.2 gallon per man per day
- Construction: 1.5 gallons per man per day
Total Division Factor = 18.2 G/M/D

2. Multiply the Division Factor (18.2) by the number of personnel in the division (16,000 men) to get the Division Consumption:
- 18.2 x 16,000 = 291,200 gallons per day

3. Add a 10% waste factor to account for spillage and inefficiencies:
- 291,200 + (291,200 x 0.1) = 291,200 + 29,120 = 320,320 gallons per day

Result: The division requires 320,320 gallons of water per day.

To calculate the volume of fluid in a pipe:

1. Measure the diameter (D) of the pipe in inches.
2. Measure the length (L) of the pipe in feet.
3. Use the formula:
$ V = D^2 imes 0.041 imes L $
- Where:
- $ V $ is the volume in gallons
- $ D $ is the diameter in inches
- $ L $ is the length in feet

Example Calculations:
• For a pipe with D = 42 inches and L = 30 feet:
$ V = 42^2 imes 0.041 imes 30 = 19.68 $ gallons
• For a pipe with D = 16 inches and L = 30 feet:
$ V = 16^2 imes 0.041 imes 30 = 62.4 $ gallons
• For a pipe with D = 10 inches and L = 25 feet:
$ V = 10^2 imes 0.041 imes 25 = 102.5 $ gallons

Five steps to treat water using chlorine produced by the Mini-WATA:
1. Produce chlorine
2. Test the chlorine concentration with WataTest
3. Treat water by adding chlorine
4. Test free residual chlorine with WataBlue
5. Water is safe to drink!

Power supply options:
• The Mini-WATA is supplied with clips that can be coupled to a solar panel of minimum 10 watt.
• If there is access to electricity, the Mini-WATA is supplied with a transformer that can be simply plugged into the network.

Materials: User guide 'Mini-WATA'

1. Choose a cool, ventilated, and sunlight-shielded location with children to produce chlorine.
2. Explain the role of saturated brine in chlorine production. Demonstrate its preparation according to the user guide 'Mini-WATA' and label it:
- Saturated brine is water with the maximum possible amount of salt.
- It helps dose the correct amount of salt for chlorine production.
- It can be stored indefinitely and reused, but ensure there's always salt remaining at the bottom of the container.
3. Ask one child to practice preparing saturated brine while others observe and comment.
4. Demonstrate chlorine production using the Mini-WATA according to the user guide:
- Chlorine concentrate can be produced with a solar panel or grid power.
- The Mini-WATA produces 0.5 litre of chlorine concentrate in five hours.
- When connected to the power supply, bubbles will emerge from the container, indicating the process is working.
5. Distribute a log-book (see page 114) and assign someone to record chlorine production details.
6. Have one child practice producing chlorine while others observe and comment.
7. While the Mini-WATA runs, discuss maintenance, shelf life, and safety:
- Maintenance: Rinse the Mini-WATA with clear water after each use and avoid running it for ten hours straight.
- Shelf Life: Use active chlorine within 24 hours of production.
- Safety:
- Do not inhale concentrated chlorine.
- Work in a well-ventilated area.
- Never use metallic containers during the procedure.
- Do not drink the concentrated solution.
- Avoid spilling it on clothing due to its bleaching power.
8. To avoid waiting five hours, proceed with the next step and return later when production is complete.

Materials needed:
• 0.5 litre of liquid chlorine at 6 g/l produced in advance
• 3 water samples with different amounts of chlorine
• 3 jerrycans (20 litres)
• 60 litres of water from a source used for drinking
• Log-book to record chlorine production
• Paper and pen

### Tools Needed:

• 3’ of garden hose that just fits over the filter spout
• 1 hose clamp (if available)
• Funnel (can be made from the top of a soda or water bottle)
• Bleach solution (1/2 teaspoon bleach to 2 liters of water). Note: Do NOT pour chlorine bleach into the top of the filter!

### Steps:

1. Place the garden hose over the filter spout.
2. Clamp the hose in place with the hose clamp.
3. Place the funnel on the other end of the garden hose.
4. Hold the funnel higher than the top of the filter, and pour 2 liters of bleach solution into the funnel.
5. Hold in place for 2 minutes.
6. Remove the garden hose and drain the bleach solution.
7. Wipe the outside of the spout with a clean, bleach-soaked cloth.
8. Add 20 liters of water to the top of the filter to flush the bleach out. Important: Instruct the user not to use this water for drinking or cooking.
9. Place the lid on the filter.

The schmutzdecke or biolayer is the key bacteria removing component of the filter.

• Without it, the filter removes some contamination through screening of the particles and microorganisms (only 30–70% removal efficiency).
• A good schmutzdecke will remove 90–99% of biological pathogens.
• It may take 10 – 20 days to establish the schmutzdecke.

Water usage during establishment:
• The water from the filter can be used during the first few weeks while the schmutzdecke is being established if a safer water source is not available, but chlorination is recommended at least during this time period.
• The schmutzdecke is NOT usually visible – it is not a green slimy coating on top of the sand.

Tools Needed:
• Measuring container with 1 liter mark
• Stopwatch
• Bucket

Procedure Steps:
1. Fill the filter to the top with water.

2. Place your measuring container under the spout to collect the outlet water.

3. Measure the time it takes to fill the container to the 1 litre mark. It should take between 50 – 80 seconds.

4. If it takes longer than 80 seconds, the flow rate is too slow:
- The filter will still work, but it may clog faster and more often, requiring more maintenance
- If it takes too long to get a pail of water, the user may not like the filter and may use untreated water
- The flow rate can be improved by “swirling” the top layer of the sand and then scooping out the dirty water
- If a few “swirl & dumps” do not improve the flow rate substantially, the sand is either too fine or too dirty – you will have to rewash the sand

5. If it takes less than 50 seconds to fill the measuring container to 1 litre, the flow rate is too fast:
- The filter may not function effectively
- The media should be replaced with finer media (less washed)
- A less preferable option is to run a considerable amount of water through the filter until the flow rate decreases (due to the capture of finer particles and faster growth of the biolayer)

Note: The flow rate through the filter decreases as the height of the water in the influent reservoir drops. As the water level reaches the diffuser, treated water may only drip out of the filter spout. It can take 40 – 90 minutes for the 20 liters in the reservoir to completely pass through the filter.

Tools Needed:
• Diffuser
• 40 – 80 liters of water

Procedure Steps:
1. Place the diffuser plate on the ledge inside the filter. Ensure that it fits snugly.
- Note: The diffuser must not be touching the surface of the water at its resting level. That would greatly reduce the amount of oxygen in the standing water layer, affecting the survival of the Schmutzedecke.

2. Place a receiving container under the spout. The water that it captures can be reused.

3. Pour the cleanest available water into the filter (turbidity < 30 NTU).

4. Observe the water coming out of the spout.

5. Continue adding water to the filter until the water coming out of the spout is clear. This may take 40-80 liters (10-20 Gallons).
- Note: If the outlet water doesn’t run clear after 100 liters (25 Gallons), the gravel or sand was too dirty to start with. It is probably easiest to take the media out, wash it in pails, and then place it back in the filter.

Procedure:

1. Do not discard stored water unless it is visibly contaminated or spoiled.
2. If the safety of your stored water is in question, use a water purifier, such as liquid household bleach, to treat it.
3. Purify water in small batches at a time as needed for consumption or cooking.
4. Always ensure that the container used to carry water is not overfilled to prevent sloshing and potential spillage during transport.
5. Keep a portable water purifier on hand, such as liquid bleach, to treat stored water if necessary.

Overview:

Drinking bottle filters are convenient but require proper use to ensure water is fully purified. The most well-known example is the Aqua Pure traveller (99,000g, 24cm diameter). Here's how to use it effectively:

Steps for Use:
1. Fill the Aqua Pure bottle with untreated water.
2. Squeeze the water into a drinking cup for purification.
3. Insert an iodine sleeve into the carbon micro-filter of the bottle (if available).
4. Allow the purified water to stand for 15 minutes after passing through the system to ensure complete disinfection.

Important Notes:
• These filters can be misleading, as they may give the impression that you can drink directly from the bottle without additional steps.
• Always allow sufficient contact time with the iodine sleeve for effective purification.

Overview:

Choosing an appropriate water purification system depends on the size of your group, the conditions of your expedition, and the availability of resources. Here is a guide to selecting the right method:

For Large Groups:
• Consider chlorination, especially if you can monitor the condition of treatment tanks.

For Smaller Groups:
• Use iodine, provided that all members tolerate it.

For Mobile or On-the-Move Groups:
• Strain water through a Millbank bag and provide each member with their own small bottle of iodine or chlorination tablets to treat water after drawing it off into individual canteens. The strained water can be used for boiling (e.g., for beverages).

Alternative Option:
• Use water bottles with attached filtration/purification systems, such as the Aqua Pure. These are convenient but require a contact time of at least 15 minutes after squeezing the water through the filter and letting it stand.

Recommendation:
All field parties should be equipped with:
• Small Millbank bags for straining water.
• A method of chemical sterilisation, such as iodine or chlorination tablets, or a portable filtration system.

To test water quality for contaminants, follow these steps:

1. Collect a sample: Use a clean, sterile container to collect a representative sample of the water.
2. Check for visible impurities: Look for any floating debris, discoloration, or turbidity in the sample.
3. Smell the water: A foul odor may indicate contamination.
4. Taste the water: An unusual taste can be an indicator of chemical or microbial contamination.
5. Use a testing kit: If available, use a water quality test kit to check for specific contaminants such as bacteria, heavy metals, and pH levels.
6. Record results: Document all observations and test results for future reference.
7. Take action based on findings: If the water is found to be contaminated, take appropriate measures to treat or avoid using it.

Procedure:

1. If a positive sample is obtained from the original sampling site:
- Collect a 100 ml follow-up sample from the original positive spigot.
- Collect one additional 100 ml sample within 5 outlets upstream of the original positive sample.
- Collect one additional 100 ml sample within 5 outlets downstream of the original positive sample.

2. If the original positive sample was at the end of a distribution line, collect two samples downstream (within 5 outlets) from the original sampling site.

3. For systems with a single outlet, tankers, trailers, bladders, Lyster bags, or 5-gallon cans, collect three 100 ml samples from the original positive sampling site.

4. When testing the three 100 ml samples using the membrane filter technique, you may:
- Filter each 100 ml sample through a single filter, or
- Combine all three samples (300 ml) and filter them through a single filter.

5. The water is considered safe to use when the set of follow-up samples are total coliform negative.

Before purchasing a treatment system, first have your water analyzed by a state certified laboratory to determine the quantity of foreign material in your water. The most common water tests are for: Coliform Bacteria, Nitrates, pH, Total Dissolved Solids, Hardness, Iron and Manganese.

Objective: Recognize common sources of water contamination to prevent illness.

Procedure:
1. Inspect water sources visually for signs of contamination such as:
- Presence of waste (e.g., feces, trash)
- Animal activity near the water source
- People washing clothes or bathing in the water
2. Look for biological indicators like:
- Algae growth
- Unusual coloration (e.g., green, brown, or murky appearance)
3. Avoid drinking from contaminated sources, such as rivers with visible waste or feces.
4. Be aware of illness symptoms associated with unsafe water consumption, including:
- Diarrhea
- Vomiting
- Fever
5. Report contamination to local authorities if possible to prevent further exposure.

Heavy metals are not common in most areas but can be a concern in certain regions.

### Steps:
1. Test the water using a lab test or consult your county health department to identify heavy metal contamination.
2. Heavy metals are more likely to be present if you live downstream of mining tailings or factories.
3. If heavy metals are found, they may affect an entire region rather than just one household.
4. For short-term use, heavy metals are unlikely to cause immediate problems, but long-term exposure should be avoided.

Organic compounds such as chloroform, gasoline, pesticides, and herbicides can contaminate water sources.

### Steps:
1. Test the water using a lab test to identify organic contaminants.
2. Groundwater is unlikely to suddenly become contaminated unless chemicals enter the well or aquifer directly.
3. One exception is when the aquifer is located in limestone, as this rock allows faster water flow and can form vertical channels or sinkholes that rapidly allow contamination from surface water.
4. Surface water may show large variations in chemical levels due to factors like rainfall, seasonal crop cultivation, and industrial effluent.

Overview: A hand-powered reverse osmosis (RO) watermaker is used to desalinate seawater into fresh water by forcing it through a semi-permeable membrane. This procedure outlines the operation of such devices, particularly models like the PUR Survivor 35.

Steps:
1. Prepare the unit: Ensure the device is assembled correctly and that all components (piston, prefilter, membrane) are in good working condition. Replace O-rings every 600 hours of use as recommended by the manufacturer.
2. Attach the intake hose: Connect the intake hose to a source of seawater or brackish water. Ensure the hose is free from kinks and that the flow of water is unobstructed.
3. Install the prefilter: Replace the prefilter regularly, as it is essential for removing large particulates before the water reaches the membrane. Failure to do so can clog the membrane and reduce efficiency.
4. Pressurize the system: Use the hand pump or waste water from previous cycles to pressurize the back side of the piston. This pressure forces seawater through the semi-permeable membrane, separating pure water from salt and contaminants.
5. Collect purified water: The purified water will be collected in a separate container. Note that only about 10% of the input water is usable; the remaining 90% becomes waste water.
6. Monitor performance: Check for any signs of membrane failure or damage, such as reduced output or unusual taste/odor in the water. If issues arise, discontinue use and inspect the unit.
7. Maintain the system: After each use, clean the prefilter and ensure that no petroleum products come into contact with the membrane, as they can damage or destroy it. Apply a biocide to the membrane occasionally if necessary.

Notes:
• These units require significant physical effort to operate, especially in prolonged survival scenarios.
• Some survival experts question their practicality due to the labor required, but many survivors credit these devices with saving their lives during maritime emergencies.
• The Survivor 35 model can also be used as a handheld unit when disconnected from its power source.

Overview: Proper maintenance of a reverse osmosis watermaker is essential to ensure its longevity and effectiveness in producing clean drinking water.

Steps:
1. Replace O-rings regularly: Replace the O-rings every 600 hours of use, as recommended by the manufacturer (e.g., PUR). This prevents leaks and ensures smooth operation of the piston mechanism.
2. Change the prefilter frequently: The prefilter should be replaced on a regular basis to prevent clogging of the membrane. A clogged filter can reduce water output and potentially damage the unit.
3. Avoid contact with petroleum products: Ensure that no oil, gasoline, or other petroleum-based substances come into contact with the membrane. These substances can permanently damage or destroy the membrane.
4. Treat the membrane with biocide when necessary: If contamination is suspected or if the water has a foul odor, treat the membrane occasionally with an appropriate biocide to eliminate bacteria and other microorganisms.
5. Inspect for wear and tear: Regularly check all components (piston, hose connections, filter housing) for signs of damage or wear. Replace any damaged parts immediately.
6. Store properly when not in use: If the unit is not being used for an extended period, store it in a dry, cool place to prevent corrosion and degradation of materials.

Notes:
• Units designed for production use may last longer than handheld models (up to a year or more), but regular maintenance is still required.
• Always follow the manufacturer’s guidelines for specific maintenance intervals and procedures.

Overview: While reverse osmosis is highly effective at removing many contaminants from water, it has certain limitations that users should be aware of.

Key Limitations:
• Rejection rates vary by contaminant type: The membrane is more effective at rejecting salts than non-ionized weak acids and bases (e.g., phenols, chlorinated hydrocarbons) or small organic molecules with molecular weights below 200. Larger organic molecules and all pathogens are generally rejected.
• Membrane imperfections: There is a possibility that some contaminants may pass through the membrane due to imperfections or damage over time.
• Not suitable for high contaminant levels: Reverse osmosis filters designed for municipal or private water systems are not effective at removing contaminants present in seawater. They require normal water pressure and are not intended for desalination.
• Mineral depletion: The purified water produced by reverse osmosis is close to pure H2O, which means users may need to increase their intake of minerals from other dietary sources to compensate.

Notes:
• Users should be aware that even with proper maintenance, no filter is 100% effective at removing all contaminants.
• In survival situations, it is important to have backup water purification methods in addition to reverse osmosis.

Procedure:

1. Inspect the color of any vegetable fluid before consumption.
2. If the fluid is milky, red, or colored in any way, it must be considered dangerous to both drink and touch.
3. Avoid contact with the skin, as some milky saps can cause severe reactions such as sores or blindness if they enter the eyes.
4. The only exception known is the Barrel cactus (USA), which may contain safe fluid.
5. Even clear fluids should be tasted first to confirm safety.

Notes:
• Many weeds have milky saps that are extremely poisonous.
• Saps from the ficus family may contain latex or natural rubber and can also cause harm.

Procedure:

1. Look for surface roots near the base of trees or plants.
2. Use a tool to cut the roots close to the tree, ensuring each root is lifted and pulled out.
3. Cut the roots into 3-4 feet lengths.
4. Place these sections in a trough or container to allow the fluid to drain.

Warnings:
• If the roots are not broken or cut into sections, the fluid will not flow, leading to the false conclusion that the root is dry when it may actually contain moisture.
• Cutting the roots helps release the stored water by breaking the capillary channels.

Notes:
• Water from plants is generally more plentiful in gullies than on ridges.

Procedure:

1. Break the roots or branches into 3 feet lengths.
2. Stand these pieces in a trough made of bark.
3. Place a container beneath the trough to collect the fluid that drains from the root or branch.
4. Ensure the collected fluid is used within 24 hours, as it may begin to ferment and become unsafe after this time.

Warnings:
• Do not assume the drinkability of the sap based on the appearance or properties of the foliage.
• Some plants, such as Eucalyptus, have sap that is safe to drink even though their leaves are toxic.
• Always test the fluid by tasting it first. If it is tasteless or nearly flavorless, it is likely safe to drink.

Notes:
• The roots of Eucalyptus can be up to 12 to 25 meters long and are found at low depths.
• Remove the bark from the root before placing it in a container to allow the sap to flow freely.

### Materials:
• Images of “Personal water use”

### Procedure:
1. Distribute images: Give each child an image titled “Personal water use” and let them look at the images.
2. Describe water usage: Ask children to describe the water use depicted in their images before hanging them on the wall.
3. Link water to hygiene: Inform children about the relationship between water and hygiene, including:
- Water is used for many hygiene behaviours, such as hand washing or brushing teeth.
- While water is essential for life, it can also cause illness and death if not properly managed.

### Educational Goals:
• Raise awareness of daily water usage.
• Highlight the importance of water in maintaining personal hygiene.

### Materials:
• 2 PET bottles
• 0.5 litre raw water
• 5 grams of salt
• 1 syringe

### Procedure:
1. Symbolise all Earth’s water: Fill the first bottle with water to represent all the water on Earth.
2. Show freshwater availability: Pour about 3% of the water (approximately one soup spoon) from the first bottle into the second bottle. This represents Earth's freshwater.
3. Illustrate undrinkable seawater: Add salt to the first bottle to symbolise seawater, which is not drinkable.
4. Represent frozen freshwater: Use a syringe to extract one drop of water from the second bottle and let it fall to the floor. This drop represents the frozen freshwater found at Earth’s poles.
5. Highlight human use of water: Emphasize that this single drop symbolises the water available worldwide for human use, with about 95% used in agricultural and industrial activities.

### Discussion Points:
• Water is a scarce and precious resource.
• Water plays a central role in all large cultures and religions.
• People can survive only a few days without water.
• Preserving and protecting water is everybody’s duty.

### Materials:
• Image of the water cycle (for each group)

### Procedure:
1. Divide students into groups: Split the class into four groups and give each group an image of the water cycle.
2. Group discussion: Let children discuss the water cycle in their groups and create a story about a water drop’s journey.
3. Alternative for young children: Tell the story of a raindrop: “Once upon a time there was a raindrop floating on the sea. The sun warmed the water and the drop evaporated. It rose as water vapour. With many other drops, it formed a cloud ...”
4. Present stories: Ask one child from each group to present their story in front of the class.

### Educational Goals:
• Understand the stages of the water cycle (evaporation, condensation, precipitation).
• Encourage creativity and collaboration through storytelling.

Procedure:

1. Use iodine crystals: This method is suitable for small quantities of water.
2. Follow the Kahnn–Visscher technique:
- Dissolve a measured amount of iodine crystals in a small volume of water to create an iodine solution.
- Use this solution to treat larger volumes of water by adding it in proportion (e.g., 0.3–0.4 ml/litre).
3. Allow contact time: Let the treated water sit for a minimum of 30 minutes.

Warnings:
• This method is fiddly and not suitable for large amounts of water.
• Do not use if you have a thyroid condition, an iodine allergy, are pregnant, or are young children.

Procedure:

1. Check for contraindications: Do not use iodine if you have a thyroid condition, an iodine allergy, are pregnant, or are young children.
2. Measure the water: For small amounts of water (e.g., 1 litre), add 5 drops of 2% iodine tincture to the water. If _Giardia_ is suspected, increase to 12 drops per litre.
3. For large quantities of water, use 0.3–0.4 ml/litre of iodine tincture.
4. Store in appropriate containers: Iodine tincture must be stored in glass containers (not plastic), as it can react with non-fluorinated plastic and cause degradation or leakage.
5. Allow contact time: Let the treated water sit for a minimum of 30 minutes to ensure effective purification.
6. Reduce taste (optional): To reduce the unpleasant taste, add a small amount of ascorbic acid (vitamin C) just before consumption.

Warnings:
• Iodine tincture is hazardous if containers break; handle with care.
• Long-term use may have health concerns, though these are largely unfounded.
• Do not consume iodine-treated water immediately after treatment if the taste is too strong.

Procedure:

1. Add ascorbic acid: Immediately before consumption, add a small amount of ascorbic acid (vitamin C) to neutralise the iodine and reduce the unpleasant taste.
2. Mix thoroughly: Ensure that the ascorbic acid is fully mixed into the water for even distribution.

Notes:
• Ascorbic acid should only be added at the point of use, not during storage or purification.
• This step is optional but recommended to improve palatability.

Procedure:

1. Dig the storage pit: Ensure it is far enough away from the shelter so that covering mounds do not interfere with drainage ditches.

2. Select the tube:
- Use a flexible tube or hose no more than 25 feet long.
- For a single family, a flexible rubber tube with an inside diameter of 1/4 inch (such as surgical tubing) is ideal.
- A 2-inch flexible hose used in mobile homes and boats also works well.

3. Position the tube:
- The tube should be long enough to extend from the bottom of the water pit to within about a foot of the shelter floor.

4. Protect the tube:
- Place it in a trench about 4 inches deep, dug before roofing either the storage pit or the shelter.
- Cover the tube with earth and tie it so that the end in the storage pit cannot be accidentally pulled out of position.

5. Start siphoning:
- Hold the free end of the tube at about the height of the surface of the water in the storage pit, while pulling gently on the tube to make it practically straight.
- Exhale as much breath as you can, then place the end of the tube in your mouth and suck hard and long. (The longer the tube or hose and the larger its diameter, the more times you will have to suck to start the flow.)

6. Shut off the flow:
- Without taking the tube out of your mouth, shut it off airtight by bending it double near the end.

7. Restart siphoning if needed:
- Exhale, straighten the tube, and suck again, repeating until you feel a good flow of water into your mouth while still sucking.
- Shut off the flow by bending the tube double before taking it out of your mouth.

8. Transfer water to shelter:
- Quickly lower the end of the tube (which is now full of water) and place the closed end in a container on the shelter floor.
- Open the end to start the siphoned flow.

9. Stop the flow: When you have siphoned enough water, stop the flow by bending the tube double. Keep it closed in the doubled-over, air-tight position with a strong rubber band or string (as shown in Fig. 8.8).

10. Prevent accidental siphoning:
- Suspend the end of the tube a couple of inches higher than the surface of the water in the storage pit outside and close to where the tube comes into the shelter.
- If air accumulates in the highest part of the tube, it may block the flow. In such cases, re-start siphoning by repeating the sucking process.