The be all end all fire starting thread post everything you know and discuss!! Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids and gases from water. The goal is to produce water fit for a specific purpose. Most water is disinfected for human consumption ( drinking water), but water purification may also be designed for a variety of other purposes, including fulfilling the requirements of medical, pharmacological, chemical and industrial applications. The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination and the use of electromagnetic radiation such as ultraviolet light. Purifying water may reduce the concentration of particulate matter including suspended particles, parasites, bacteria, algae, viruses, fungi, as well as reducing the amount of a range of dissolved and particulate material derived from the surfaces that come from runoff due to rain. The standards for drinking water quality are typically set by governments or by international standards. These standards usually include minimum and maximum concentrations of contaminants, depending on the intended purpose of water use. Visual inspection cannot determine if water is of appropriate quality. Simple procedures such as boiling or the use of a household activated carbon filter are not sufficient for treating all the possible contaminants that may be present in water from an unknown source. Even natural spring water – considered safe for all practical purposes in the 19th century – must now be tested before determining what kind of treatment, if any, is needed. Chemical and microbiological analysis, while expensive, are the only way to obtain the information necessary for deciding on the appropriate method of purification. According to a 2007 World Health Organization (WHO) report, 1.1 billion people lack access to an improved drinking water supply, 88% of the 4 billion annual cases of diarrheal disease are attributed to unsafe water and inadequate sanitation and hygiene, while 1.8 million people die from diarrheal diseases each year. The WHO estimates that 94% of these diarrheal cases are preventable through modifications to the environment, including access to safe water. Simple techniques for treating water at home, such as chlorination, filters, and solar disinfection, and storing it in safe containers could save a huge number of lives each year. Reducing deaths from waterborne diseases is a major public health goal in developing countries. Sources of water Groundwater: The water emerging from some deep ground water may have fallen as rain many tens, hundreds, or thousands of years ago. Soil and rock layers naturally filter the ground water to a high degree of clarity and often, it does not require additional treatment besides adding chlorine or chloramines as secondary disinfectants. Such water may emerge as springs, artesian springs, or may be extracted from boreholes or wells. Deep ground water is generally of very high bacteriological quality (i.e., pathogenic bacteria or the pathogenic protozoa are typically absent), but the water may be rich in dissolved solids, especially carbonates and sulfates of calcium and magnesium. Depending on the strata through which the water has flowed, other ions may also be present including chloride, and bicarbonate. There may be a requirement to reduce the iron or manganese content of this water to make it acceptable for drinking, cooking, and laundry use. Primary disinfection may also be required. Where groundwater recharge is practised (a process in which river water is injected into an aquifer to store the water in times of plenty so that it is available in times of drought), the groundwater may require additional treatment depending on applicable state and federal regulations. Upland lakes and reservoirs: Typically located in the headwaters of river systems, upland reservoirs are usually sited above any human habitation and may be surrounded by a protective zone to restrict the opportunities for contamination. Bacteria and pathogen levels are usually low, but some bacteria, protozoa or algae will be present. Where uplands are forested or peaty, humic acids can colour the water. Many upland sources have low pH which require adjustment. Rivers, canals and low land reservoirs: Low land surface waters will have a significant bacterial load and may also contain algae, suspended solids and a variety of dissolved constituents. Atmospheric water generation is a new technology that can provide high quality drinking water by extracting water from the air by cooling the air and thus condensing water vapor. Rainwater harvesting or fog collection which collect water from the atmosphere can be used especially in areas with significant dry seasons and in areas which experience fog even when there is little rain. Desalination of seawater by distillation or reverse osmosis. Surface Water: Freshwater bodies that are open to the atmosphere and are not designated as groundwater are termed surface waters. Aims The aims of the treatment are to remove unwanted constituents in the water and to make it safe to drink or fit for a specific purpose in industry or medical applications. Widely varied techniques are available to remove contaminants like fine solids, micro-organisms and some dissolved inorganic and organic materials, or environmental persistent pharmaceutical pollutants. The choice of method will depend on the quality of the water being treated, the cost of the treatment process and the quality standards expected of the processed water. The processes below are the ones commonly used in water purification plants. Some or most may not be used depending on the scale of the plant and quality of the raw (source) water. _______ Water Collection Techniques If you're stranded and there isn't a fresh watersource around, then you need to get to work on collecting water. There are a few techniques to do this, and it doesn't hurt to set up more than one system. The more water you can collect, the better your chances of survival. One pretty basic way you can collect water is to make a belowground still. To do this, you'll need some plastic sheeting, a digging tool, a container, a drinking tube and a rock. Choose a moist area that gets sunlight for most of the day. Dig a bowl-shaped hole about three feet across and two feet deep, with an additional sump dug in the center. The sump should be flat and big enough to hold your container. Place the container into the sump. Put the drinking tube in the container and run it up and out of the main hole. Place the plastic over the hole and cover the sides with rock and soil to keep it there. Put your rock in the center of the sheet and let it hang down about 18 inches, directly over the container to form an inverted cone. Add more soil on the edges for stability. The moisture from the ground reacts with the heat from the sun to produce condensation on the plastic. The still forces the condensation to run down the plastic and into your container. You can also add vegetation inside the hole to increase the amount of moisture -- just make sure the plants aren't poisonous. Use the tube to drink directly from the container. If you don't have one, you can remove the container and reassemble it after. A good still can produce up to one quart of drinking water per day. For better-tasting water, let it sit for 12 hours if you can afford to. You can also make a filter to remove any visible particles: Find a large can, hollow log or plastic bag. Hollow bamboo will also work. Punch 5-10 small holes around the base of your container and suspend it from the ground. Fill it with alternating layers of rock, sand and cloth. Use both fine and coarse layers, the more the better. Pour your collected water into the filter and catch it in another container below. The water should come through fairly clear, if not you can pour it through again. Add charcoal from your fire to remove odor -- just make sure you filter the charcoal out with some cloth. This method merely removes large sediment and improves the taste. You should always purify the water by boiling it. In the next section, we'll look at some other techniques for collecting water LIFESTRAW The Lifestraw is a portable filtration device that lets you safely drink directly from any fresh water source. It's about 11 inches long, less than 1 inch around, and looks like a jumbo drinking straw. One end has the narrow mouthpiece, the other goes directly into the water source. Each Lifestraw lasts 700 liters, roughly the amount of water needed for one person per year. The filter gets rid of nearly 100 percent of waterborne bacteria, 98.7 percent of viruses and removes particles as small as 15 microns. Five million people per year die from waterborne illness -- mostly children. More than a billion people worldwide have no access to safe drinking water. The makers of Lifestraw hope to help cut this amount in half by the year 2015. You can donate money through two organizations to help provide Lifestraws to people in need all over the world at the Lifestraw Web site. Lifestraw is also a great item for any outdoor enthusiast to have in his or her emergency survival kit. It weighs only 140 grams and it just might make the difference in your chances of survival.