If your water comes from a private source, such as a ground well or flowing spring, there are some important facts you should know.
v People drawing water from private wells are responsible for assuring that the water is safe for consumption.
v The U.S. Environmental Protection Agency only requires that municipal water sources be tested for about 80 of the 75,000 known contaminants.
v The standards for safe drinking water are established for a 175-pound healthy adult and may not be satisfactory for children, women who are pregnant or nursing, or adults with compromised immune systems.
There are many methods that can be used to purify water and each one is best for removing a certain type of impurity or contaminant but may not be effective at all for others. Some of the more common water purification technologies are:
v Distilliation – Water is heated to boiling and then cooled to condense the water vapor. Impurities are filtered out by the evaporation
o Effective for: bacteria, lead, nitrate, sodium chloride, organic chemicals and pesticides
o Pros: removes a wide range of contaminants, reusable
o Cons: slow, requires a large amount of water and energy
v Carbon Filtration – Water is passed through an activated carbon filter that absorbs odors, flavors, organic compounds and many hazardous chemicals
o Effective for: hydrogen sulfide, radon, chlorine, volatile organic compounds, pesticides, benzene, colors and orders
o Pros: removes objectionable odors and flavors
o Cons: won’t remove heavy metals and the filter must be replaced periodically
v Ion Exchange – water is percolated through a layer of resin beads that have a sodium exchange coating to “soften” water before using other treatment methods
o Effective for: nitrates, sulfates, fluorides, iron, magnesium, calcium and manganese
o Pros: removes dissolved minerals and metals effectively at a relatively low initial cost
o Cons: doesn’t remove bacteria – in fact, beads can become breading ground for bacteria
v Micro Filtration – water is passed through a porous filter to remove sediments and suspended materials
o Effective for: sediments
o Pros: removes all suspended impurities larger than filter pore size
o Cons: doesn’t removed dissolved contaminants
v Ultraviolet Radiation – low level ultraviolet light kills bacterial and viral pathogens but leaves no radioactive trace
o Effective for: bacteria, viruses
o Pros: sanitizes water
o Cons: doesn’t remove suspended particles or ions
As you can see, no single purification method removes ALL the contaminants from water and you may have to employ several methods to make your water safe for drinking and cooking.
Dying of thirst while surrounded by water is a nightmarish scenario, and until recently, even the most fresh-looking seawater was strictly off-limits for human consumption. Although it may resemble clear and clean potable water, seawater is filled such high levels of salts that the human body is incapable of metabolizing it when ingested, as average ocean saline levels are triple of that normally found the bloodstream. Drinking large quantities of seawater can result in extreme dehydration, leading to seizures, kidney failure and eventually, brain damage and death. Hence, innumerable unlucky mariners have identified with Samuel Coleridge’s famous line of prose, “Water, water, every where, nor any drop to drink.” However, new filtration technology may make one of the most dreaded seafarer’s deaths a piece of history.
Without the need for a hand pump or electrical unit, the SeaPack Saltwater Desalination Unit is small enough to fit in a life raft, small boat or even backpack, and is capable of processing a life-sustaining half a litre of drinking water within 4 hours. The proprietary filtration system uses sugar syrup to speed the process of forward osmosis, which draws the saline and other minerals in the seawater through the filter membrane, leaving safe drinking water behind. This product is reportedly the first portable osmotic filter for desalinization, and this infant technology is certain to become larger in scale and availability. Portable desalination and filtration systems using this type of filter are currently used by NASA, the US Department of Defence and Coast Guard, and are invaluable in preventing dehydration and the spread of communicable diseases after hurricanes and tropical storms.
Water harvesting is one of the oldest ‘crops’ in the world. As long ago as 2,000 years, human civilizations have relied on rain to settle, sustain, and sow land of all variety. Deserts in the Negev, nomads in Africa, and elaborate Roman villas in Italy have all been designed to exploit the common aspects of rain collecting. The efficacy of the practice is testified to by the fact that water harvesting is still around today. The world’s largest existing water tank was built around 600 B.C. and remains standing and in use in Turkey. Remote areas are still dependent on some amount of rainfall for a variety of purposes…any one of which is part of the mosaic of human survival. Rain water allows for supplementary crop maintenance, dilution, human consumption, and support for a variety of livestock.Islands are common locations for water harvesting, especially using rainwater. Islands that are relatively close to a mainland often have water piped or carried in. Despite any distinctions between island and mainland rainwater harvesting, there are three common engineering elements: collection, conveyance, and storage. How these three interrelated elements are applied to their environment, however, vary greatly between urban and island environments. Read more »
Ultraviolet water purification lamps produce UV-C or “germicidal UV.” UV light is capable of killing microorganisms such as bacteria, viruses, molds, algae, yeast, and oocysts like cryptosporidium and giardia. Ultraviolet purification is considered the most effective technology for eliminating biological contaminates in a water supply available to homeowners. There are no known organisms immune to its effect and it’s generally regarded as being able to kill more than 99.99% of bacteria. Next to bacterial eradication the biggest advantage of UV purification is that it does not introduce any chemicals into the water, it does not alter the taste, it produces no byproducts and it does not alter the pH or any other properties of the water. In addition the system is energy efficient requiring the same amount of power as a 60W light bulb. The downside of UV filtration is that it has no effect on chlorine, heavy metals, smell or other chemical contaminates. UV lamps (bulbs) need to be replaced on a yearly basis. It is important to remember that UV light is not visible therefore the lamp may be producing light but not necessarily UV light. Therefore, after one year there is no guarantee that the lamp is producing sufficient UV to kill microorganisms. UV lamps cost between $450 and $700 depending on the type of system and replacement bulbs cost approximately $80.
Carbon filters have been used for several hundred years and are considered one of the oldest means of water purification. Carbon filtering is a method of filtering that uses a piece of carbon to remove contaminants and impurities. Each piece of carbon is designed to provide a large amount of surface area, in order to allow contaminants the most possible exposure to the filter. Carbon used for water filtration is generally activated with a positive charge. This is done so as to attract negatively charged water contaminants. Carbon filters are most effective at removing chlorine, sediment, and volatile organic compounds (VOCs) from water. They are not generally effective at removing minerals, salts, and dissolved inorganic compounds. Thus they are often used in combination with reverse osmosis systems which remove these types of impurities. Most often it is used in combination with a reverse osmosis system.
Carbon filtrations systems are the most effect means of removing organic compounds, chlorine and radon. In addition, carbon filtration is a very cost effective means of water purification. It is crucial that a schedule of filter replacement is followed due to the tendency for bacteria to build up on the carbon thus reducing its efficiency.
Cost of Carbon Filtration
Carbon filtration systems typically cost between $300 and $400 but can cost more depending on the type of system. Replacement cartridges can cost between $20 and $75 depending on the type of system used.