When you find yourself in an emergency situation with no clean water on hand, it's important to know how to filter the water so you don't make the situation more complicated by getting sick. Obviously, if you enjoy the luxury of a preventive preparation, you can choose the most comfortable solutions for your camping trip or you can even decide to install a permanent filter at home.
Steps
Method 1 of 4: Camping
Step 1. Consider a physical filter
"Filter pumps" are the cheapest choice in this category, but they are slow and tedious to use. If you plan to camp for a long time, we also recommend "gravity filters", which consist of two bags joined by a tube. The bag with the filter is filled with water and hung to allow the water to percolate into the filter and reach the "clean" bag. This is a quick, convenient method that does not require carrying spare filters.
These solutions are ineffective against viruses but kill bacteria. Not all natural areas require protection against viruses, however, check with the tourism office of your local ASL for the specific characteristics of the country you want to go to
Step 2. Learn the features of chemical disinfection
Disinfectant tablets are slow but inexpensive and are effective against viruses and bacteria. There are two types:
- Iodine tablets: must be left in water for at least 30 minutes. They are often sold in combination with other tablets that mask the iodine flavor. Pregnant women and people with thyroid problems shouldn't use them while anyone shouldn't rely on them for more than a few weeks.
- Chlorine dioxide tablets: require a 30 minute waiting time. Unlike iodine, they are also effective against Cryptosporidium bacteria if, and only if, you wait for them to act for at least 4 hours before drinking.
Step 3. Try ultraviolet treatment
These are UV lamps capable of killing viruses and bacteria, but only if the water is transparent and the light is applied for a long time. Each model (there are also light pens) has a different intensity of light, so always follow the instructions provided by the manufacturer.
Step 4. Boil the water
This is a very effective method of killing pathogens if you wait at least a minute. Perhaps it is not very convenient to boil water several times a day, but know that no additional filtration is required if it is water for coffee or for cooking meals.
At high altitudes, the water must be boiled for at least 3 minutes, as it boils at lower and lower temperatures as you move away from sea level. It is the temperature and not the boil that kills the bacteria and viruses
Step 5. Use stainless steel water bottles
Plastic ones are designed to be filled and used only once, as the plastic material degrades over time and could release dangerous chemicals into the water and become a favorable habitat for bacterial proliferation. Even aluminum is often coated with plastic and is not dishwasher safe, so it cannot be thoroughly sanitized.
Step 6. Drink directly from the source
If you are lucky enough to find a mountain with water flowing from it, know that it is usually drinking water. However, as soon as you move away from the source (even by just half a meter) the water is no longer considered safe.
This is not a 100% certain rule and could be a risk in agricultural areas, with a past of mining or those that are not very high and close to urban centers
Method 2 of 4: In Emergency Situations
Step 1. Use a fast-acting filter in an emergency
Filter the water through a bandana, a T-shirt or a coffee filter to eliminate visible residues. Wait a few minutes for the particles to settle to the bottom of the container. If possible, boil it before drinking it to eliminate pathogens. The following steps will teach you how to “build” a more effective filter but, unless you have an activated carbon one, be aware that the process takes several hours.
Step 2. Prepare some charcoal
This element is an excellent water filter and is used to build commercial ones. If you are able to light a fire you can make charcoal even in the wilderness. Light a wood fire and let it burn completely. Cover it with earth and ash and wait a few hours before digging it up. When it is completely cold, break the charred wood into small pieces or even into dust. You just made coal.
While not as effective as commercial "activated charcoal," which isn't feasible with makeshift tools found in the wild, this homemade charcoal should be enough to filter your water if you're in an emergency situation
Step 3. Prepare two containers
You need an "upper tank" with a small hole in the bottom and a lower one to collect the clean water. Here are some options:
- If you can get a plastic bottle, cut it in half and use the halves as containers. Make a hole in the cap and use it as a filter hole.
- Alternatively, use two buckets, one of which you need to drill a hole.
- In emergency conditions where you have to survive and have few tools available, look for a hollow plant such as bamboo or a felled trunk.
Step 4. Cover the top of the hole in the container with a cloth
Spread the fabric well to cover the hole and make sure the cloth completely covers the inner base of the "tank" otherwise the coal will be washed off.
Step 5. Pile the bits or dust of charcoal on top of the fabric
Compact them as much as you can; for the filter to be effective, the water must slowly percolate through the carbon. If the water flows too easily, you will have to try again by compacting more coal. You should get a thick, even layer that half-fills the container (if you're using half a plastic bottle).
Step 6. Cover the charcoal layer with gravel, sand and another cloth
If you have another cloth available, use it to cover the charcoal so the particles don't get lost in the water when you pour it. Regardless of the cloth, don't forget to add a layer of sand or pebbles to block larger particles and hold the charcoal in place.
You can also use leaves and grass if you are sure they are not poisonous species
Step 7. Filter the water
Place the upper container on top of the lower one so that the charcoal is facing down. Pour the water into the top container, check that it drips through the filtering system and then falls into the tank at the bottom.
Step 8. Repeat the process until the water runs clear
You will need to filter it two or three times before all the particles are removed.
Step 9. If possible, boil the water
The filter system described above removes most of the toxins and bad odors, but is often ineffective against bacteria. Boiling guarantees additional safety.
Step 10. Change the filtration layers from time to time
Sand and gravel contain microbes and other contaminants that are unsafe to drink. After using the filter a few times, remove the layer of sand and replace it with another clean one.
Method 3 of 4: Commercial Filter for Household Use
Step 1. Check which are the contaminants present in the water
You can do online searches on the ARPA website in your region or rely on other sources of information. You can also contact the company that deals with water distribution and ask for a quality report or ask a local ecological organization.
Step 2. Choose the type of filter
Once you know the chemical elements that are dissolved in the water, you can find the most suitable filter by reading the specifications on the label or online; in this way you can realize if a certain product is able to eliminate the contaminants you are dealing with. However, here are some tips to help you choose:
- Carbon filters are inexpensive and widely available. They filter most of the contaminants including lead, mercury and asbestos.
- Reverse osmosis filters retain inorganic contaminants such as arsenic and nitrates. They are extremely inefficient and should only be used if you are sure that the water is contaminated with elements that a carbon filter is not able to eliminate.
- The deionizing filters remove minerals making the hard water softer. They do not remove contaminants.
Step 3. Choose the type of installation
There are many models on the market that are designed to meet various needs. Here are the most common for home use:
- A carafe. They are the most convenient for home use, you can fill the jug once or twice a day and store it in the refrigerator.
- At the tap. This model is mounted directly to the kitchen faucet and filters the water directly, however it requires a slow flow of water.
- Above or under the kitchen counter. These models must be installed by a plumber because piping changes have to be made, however they have a longer life and require less maintenance.
- If the water is so contaminated that it is not even safe for the bathroom, install a filtration system for the whole house.
Step 4. Fit the filter according to the manufacturer's instructions
Each filter comes with an instruction manual that explains how to mount it and make it work. In most cases, installation is not difficult but, if you have any difficulties, call the manufacturer's customer service number.
Step 5. Run the water through the filter
Open the cold water and let it flow into the filter, usually the access is at the top of the filter itself, so it can percolate through the system more easily to eliminate impurities. Clean water flows from the bottom and you can collect it with a bottle, with a jug, or it flows directly from the tap (depending on the filter model you purchased).
- Do not submerge the filter while water is flowing through it because the one that flows back may not be purified.
- Some types can be damaged with very hot water, always check the instructions provided by the manufacturer.
Step 6. Change the cartridge as recommended
After a few months of use, the activated carbon in the filter clogs up and stops working properly. Buy a new cartridge suitable for your model from the same manufacturer.
Some filters last longer than others. Always check the instructions for specifications or contact the manufacturer
Method 4 of 4: Homemade Ceramic Filter
Step 1. Get everything you need
Household ceramic filters exploit the porosity of this material. The holes are small enough to block the passage of contaminants but, at the same time, allow the water to filter. To proceed you will need:
- A ceramic filter element. You can purchase a candle or "pot" filter for this purpose. Both are available online and in home improvement stores. Choose one that meets all the safety requirements imposed by the European Community and that specifies the percentage of impurities that it is able to filter to make the water drinkable.
- Two buckets for food use. One is used for "impure" water and the other for clean water. You can buy them at homewares stores or you can ask a restaurant in the area if they can give you two.
- One tap. This is fixed to the bottom of the bucket to be able to extract the drinking water.
Step 2. Drill holes in the buckets
You will need three openings: one on the bottom of the upper bucket, one on the lid of the lower bucket and the last on the bottom of the lower bucket where you will attach the tap.
- Start with a 1.2 cm diameter hole right in the center of the bottom of the top bucket.
- Make a second hole (also 1.2 cm) in the center of the bottom bucket lid. This must be perfectly aligned with the first. The water passes from the first bucket to the second, dripping between the two openings.
- On the wall of the second bucket, near the bottom, make a hole of 1.8 cm. Here you will attach the faucet, so make it so that it is 2.5-5 cm from the bottom.
Step 3. Install the faucet
Follow the instructions that you will find in the package and insert it into the hole. Fix it from inside the bucket and make sure it is firmly in place.
Step 4. Assemble the filtration system
Insert the ceramic element into the hole of the upper bucket so that it rests on the bottom of the same and that its "spout" protrudes outside. Place the upper container over the collection bucket so that the spout passes through the hole on the latter's lid. At this point the filter is assembled.
Step 5. Filter the water
Pour the non-potable one into the container on top. It should start percolating through the filter, come out of the spout and drip into the dirt container. The process could take a few hours, depending on the amount of water to be purified. When you have enough quantity in the bottom bucket, use the tap to access it. This is drinking water.
Step 6. Clean the filter
The impurities present in the water collect at the bottom of the upper bucket which must be cleaned from time to time. Every 2 to 3 months, take the filter apart and clean it with vinegar or bleach to sanitize it. Clean it even more often if you use it frequently.
Advice
You may notice black particles suspended in the jug of water after installing a commercial filter for some time. It is carbon coming from the filter itself; it is not dangerous but it is a sign that the filter must be replaced
Warnings
- Water filtered with a homemade system may still not be potable. If you feel unwell after drinking it, call a doctor right away.
- You cannot filter seawater at home to make it drinkable, even though there is research in this regard.
