Tuesday, July 24, 2012
Just in case...
We all know that three days without water and we are incapacitated and nearing death. We all know that water from streams, lakes, ponds and rivers if consumed “raw” can lead to parasitic infection. We also know that those same sources may be polluted with pesticides, insecticides, heavy metals, and a host of other contaminants. These can lead to sickness and to death.
If you find yourself in a situation where it is drink or die, then drink of course and hope for the best, right? In a worst case scenario that might be the only choice you have, and you might very well get lucky. A better alternative is to know how to treat the water so that it is safe. The following techniques require at least a fire-safe container, or plastic sheeting, or PET bottles, bleach or iodine.
The simplest technique of removing parasites is to boil the water. Pasteurization will take place at just 160 degrees F after 6 minutes. Bringing water to a boil and letting it cool off will also do it [but it is overkill. You don’t need to actually boil the water [, but if you don't have a dairy of candy thermometer, it is one way to make sure that the microorganisms in the water are sterile or dead.] This does not remove chemical or metal content.
Treatment with common household bleach works quite well. Use regular bleach, not bleach with scents in them. The chlorine in the bleach is the same chlorine used in water treatment plants. If the water is cloudy, let it stand until the particulate matter settles, then decant the clear water – or filter the water through coffee filters or clean cloth or whole chunk charcoal. Do not use briquettes, they contain chemical binders that can leach into the water. When the water is clear add 8 drops of bleach per gallon. Stir or shake well and let it set for at least 30 minutes before drinking.
If you use tincture of iodine (2%) mix in 20 drops per gallon of clear water, shake or stir well and let set for 30 minutes. In both cases, Iodine or chlorine, use more if you cannot filter the water. How much more? There are too many variables to give a single answer. Use your best judgment. Also let it stand longer so that the disinfecting chemicals have more time to work their magic.
If heating water to 160 F isn’t possible and you don’t have bleach or iodine then there are still other methods that you can use.
Solar distillation is an effective way to remove contaminants. This is a simple process, but a slow one. It will not produce a large volume in a short time. It can keep you alive though. The materials required are plastic sheeting, clear is best, and a clean bowl or small pot. Begin by digging a large diameter hole shaped like a shallow dish bowl. The size of the hole depends on the size of the plastic sheeting you have. A manageable size would be three feet in diameter. The depth should be twice the depth of the bowl or pot you will be using. The hole should slope up on the sides to the top to maximize the amount of water surface exposed to the sun. A thin large sheet of water will evaporate faster than a deep small hole of water will.
Collect enough rocks to make a complete circle around the circumference of the hole. Lay one sheet of plastic in the hole to line the bottom. Cover the edges of this plastic with enough dirt to keep it in place. Fill this hole with water to the edges. Place the bowl or pot in the middle of the hole of water. This will be the collection container. The inside of the collection container must be clean. You may need to place a rock or piece of metal inside the collection container to keep it from floating out of position, if so make sure it too is clean.
Lay a second sheet of plastic over the top of the hole, weighing it down with the rocks you collected. Leave a little slack in this sheet. When it is secure around the edges place a small amount of dirt on the edges of the plastic. You want a fairly good seal, or you’ll lose some of the water you would otherwise be able to drink. Place a small rock on top of the top sheet directly above the collection container. This will slope the plastic down to a point above the collector. As the sun hits the plastic it will evaporate the standing water. That evaporated water will be trapped against the underside of the upper plastic and condense, then run down the plastic to the point above the collector and drip into it. When enough water has accumulated remove it and set the apparatus back up.
If you have clean flexible plastic tubing you can run the tubing to the collector, coming out the edge of the hole and suck the water out periodically, saving the work of restoring the solar still each time you collect water. If you don’t have the tubing it’s no big deal. Obviously you should choose a sunny location for the solar still, and you can make more than one to increase production. The hotter the ambient temperature, the more direct the sunlight, the faster it will work.
Another system for biological disinfection is to use the sun’s ultra-violet rays. This is a simple and easy method. It can also produce as much water as you can find containers to disinfect in. Clean, clear PET bottles of two liter or smaller size are the container of choice. Clear glass works, but not as fast.
Put clear filtered water inside a PET bottle, set it where it will be in direct sunlight, and wait four hours. The suns UV rays will kill the biologicals in the water. The bottle should be horizontal, not standing up. Angling the bottles to perpendicular to the sun is best, roof tops work well for this. Of course remove any labels that would block the sun. That’s the short explanation.
For maximum effectiveness fill the bottle ¾’s full, cap it and shake vigorously, then fill the rest of the way. This helps to introduce oxygen into the water. The oxygen enhances the UV exposure and kills pathogens faster. On partly cloudy days where you are receiving more than 50% sunlight during the day 6 hours is required. On overcast days where you receive less than 50% sunlight 12 hours. UV penetrates overcast days, but at a lower rate. This doesn’t work during heavy cloud days or rain. To be safe and if you have the time, two full days of sunlight would be optimum.
PET allows UV rays through. PVC blocks UV rays and may also introduce chemicals you don’t want. Most bottles that contain consumable liquids are PET. Clear glass works, but glass blocks some of the UV rays. If using glass then double the exposure time. This method does not remove chemical or metallic contamination, only biological. This is a system that is being introduced to third world countries around the globe. It is simple and effective, relying only on being able to find sufficient PET bottles to work. Plastic bags also work. Use sandwich type bags, or any other type of food grade clear plastic bag. Make sure the sun doesn’t have to penetrate more than four inches of water though. If the only container you have requires more than four inches of penetration, shake or move the water several times and give extra exposure time.
Another way of obtaining water is a transpiration trap. Locate a leafy bush, wrap a plastic bag around the end of the bush and seal as well as you can against the stem that you placed it over. Get as many leaves inside the bag as you can. Plants transpire, or give off water vapor, all the time. The plastic bag catches that moisture and condenses it. Periodically check the amount of water and when enough, you can probably drink it straight out of the bag. Caution – do not do this with poisonous plants such as oleanders. You might get some of the poison in the water.
If you use a clean bag that is well sealed this water might be clean enough to drink. It has been “filtered” by the plant itself and will most likely not contain contaminants. However, it can be polluted by whatever is on the leaf’s surfaces. The best thing to do is to follow the UV disinfection routine after collecting the water.
If you have towels, during a heavy dew you can collect water by dragging the towel through dew-laden grass and wring it out into a container, then collect more. This water should also be sun treated if possible, or boiled or chemically disinfected.
Fog traps can also be made. They are not difficult to make, but only work in a heavy fog. Hang large sheets of plastic or other sheet like materials and collect the water that adheres to them. With plastic, shape the bottom of the sheet into a curve that brings the water down to one point and place a container beneath it. With cloth sheets wring the sheet out periodically. This water will be as clean as the surface you collect it on. You may or may not have to disinfect it, although it is a good idea to.
Water heaters are also water storage tanks. They come with a drain valve on the bottom. Each water heater will contain many gallons of drinkable water. This is particularly handy for short term water shortage problems, such as grid power failures.
Safe drinking water is an age-old problem, and is still a major problem for much of the world’s population. In a survival situation the last thing you need is to become sick or parasite ridden. There isn’t much time, three days or so, to solve the problem. Knowing how to treat water is of paramount importance. Starting right away on the treatment process is necessary. If you can produce a surplus of water, do so, but remember to store the water in clean vessels. If the water is stored for a long period of time, treat it again. The above treatment options can leave small traces of contaminants that won’t be a problem at the time, but if stored long enough those contaminants can breed and re-infect the water.