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Water Conservation: Getting Techie
Where does it come from?
The water cycle is the process by which water circulates around, over, and through the Earth. It is driven by the sun, evaporating water from the oceans, rising through the atmosphere and condensing as pure water or snow. About 505,000 cubic kilometers of water fall on the earth each year, 398,000 over the oceans. The pure water is stored as ice, as water in lakes, and in aquifers that have taken thousands of years to fill. 97% of water is stored in the oceans; 2% in the ice caps; only 1% is in lakes, groundwater or other useable sources. We draw on surface water (lakes and rivers) subsurface (groundwater through pumping) and a small amount is made (very expensively) through desalination. Read more about the water cycle at Wikipedia.
What is done to it?
Sometimes very little. Where the water sources are pure, like in New York City, very little is actually necessary. Other municipalities put their water through a three stage system of Primary Treatment (collecting and screening), Secondary Treatment (removal of solids and contaminants using filters and coagulation), and Tertiary Treatment (carbon filtering and disinfection). It is then stored in reservoirs or water towers so that it can be gravity-fed through the system.
Is it really pure?
While the consensus is that, overall, tap water is better than bottled water for you and the environment, there are some concerns. Older houses and apartment buildings may have lead plumbing which can contaminate it via pipes, solder, and old brass fittings. There is also a growing convern about low levels of antibiotics from agriculture and people disposing of medication down the toilet. Gender-bender hormones from birth control pills, along with phthalates from vinyl, are entering the water system and changing the sex of fish http://www.raysapoint.com/contra.html , lowering the sperm count of men, and doubling the number of annual male breast reduction surgeries.
Where does it go?
Too often, waster is just dumped. Often it enters combined systems that are overwhelmed when it rains. Where there is sewage treatment it is of variable quality, but a properly run modern plant can produce results that are fairly effective. The systems are designed to mimic natural treatment processes where bacteria consume the organic contaminants, and it can then be returned to lakes or as groundwater. Unfortunately, in sub-Saharan Africa almost no waste water is treated; in Latin America only about 15% is. The price is paid in diarrhea, typhus and cholera.
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