http://www.care2.com/greenliving/reverse-osmosis-water-filtration.html
Reverse Osmosis Water Filtration
Excerpted from Real Goods Solar Living Source Book,edited by Doug Pratt and executive editor John Schaeffer.
The Environmental Protection Agency (EPA) has recently released information stating that, no matter where we live in the United States, there is likely to be some toxic substance in our groundwater. Indeed, the agency estimates that one in
five Americans, supplied by one-quarter of the nation’s drinking water systems, consume tap water that violates EPA safety standards under the Clean Water Act.
The most obvious solution to water pollution is a point-of-use water
purification device. The tap is the end of the road for water consumed by our families, so this is the logical, and most efficient, place to focus water treatment.
- Different water purification technologies each have strengths and weaknesses, and are particularly effective against specific kinds of
impurities or toxins.
- Reverse osmosis and activated carbon filtration are complimentary processes.
Combining them results in the most effective treatment against the broadest range of water impurities and contaminants.
- Reverse osmosis (RO) is a water purification technology that utilizes normal household water pressure to force water through a selective semi-permeable membrane that separates contaminants from the water. Treated water emerges
from the other side of the membrane, and the accumulated impurities left behind are washed away. Eventually sediments builds up along the membrane and it needs to be replaced.
- Reverse osmosis is highly effective in removing several impurities from
water: Total dissolved solids (TDS), turbidity, asbestos, lead and other heavy metals, radium, and many dissolved organics.
- RO is less effective against other substances. The process will remove some pesticides (chlorinated ones and organophosphates, but not others), and most heavier-weight VOCs.
- However, RO is not effective at removing lighter-weight VOCs, such as THMs (the chlorine by-product) and TCE (trichloroethylene),and
certain pesticides. These compounds are either too small, too light, or of the wrong chemical structure to be screened out by an RO membrane.
Note: RO systems have two major drawbacks.
- First, they waste a large amount of water. They’ll use anywhere from 3 to 9 gallons of water per gallon of purified water produced. This could be a problem in areas where
conservation is a concern, and it may be slightly expensive if you’re paying for municipal water. On the other hand, this wastewater can be recovered or redirected for purposes other than drinking, such as watering the garden, washing the car, etc. - Second, reverse osmosis treats water slowly: It takes about 3 to 4 hours for a residential RO unit to produce one gallon of purified water. Treated water can be removed and stored for later use.
Go to the Source
The Real Goods Solar Living Sourcebook
The Sourcebook remains the best introduction to energy-efficient technology for common folks.-Whole Earth Review
From novices to pros, this book explains renewable energy and efficient building practices. Great reference to start design and cost estimation from each section. One of the best features of this book is the addition of the National Electric Code for RE systems. It's possible to pick a building material to build a house, design a solar electric system, decide on appliances, determine the use of a greywater system, and more from 562 pages. No more looking up pages on the net!buy now
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13 comments
add your comment »I'm excitedly waiting all the changes in technology and availability of vehicles in the near future!!!
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why is this inappropriate?
Hi Sherry: Your apology is gladly accepted. I may have sounded a bit more upset than I really was. I hope we all learn as much about water filtratrion as we want and need to make good decisions.
Steve
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Hi Lim:
Well, we are talking about RO water as that is a very good way to clean up the water that we drink here in America. Personally I use a system that incorporates 3 filters. One before and one after the RO. Tastes great and my 91 yo father likes it too, every day. My energy level is pretty good at 56.
Have a great day-y'all
Steve
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Why you guys still talking baout RO water? RO water is acidic, very low energy, big molecule cluster, too much difference if compared with body water. As i know, RO Water caused our body weak, and it is significant if senior citizen drink RO Water. Just have a thought how RO water bring us health with its function! It bring us nothing! Stay away from RO water if you still love your body!
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africa is a great place to meet new friends and to understand it all from the roots, technology is fun, interesting and helpful but very easily reversed i think "it" needs a helping hand because technology has suffered enough in the past or was it the other way around not sure how to put it. im just not sure how to come up with an easier way to filtrate water without all the mumbo jumbo that we are fed to believe, and is it very nessesary to have it done from well water i guess it might have to do with the way we have been polluting in the first place speaking only to those that care about our future. as humanbeings of course. i apoligise im not proofreading my text.
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Steve,
Whoa! I didn't mean to "whine," nor am I ignorant. As I look back though, I can see why you took my comment personally and took offense. Please accept my humble apology. It did seem as though you were advertising your Shaklee product, but if you feel passionately about your product, so be it then and good luck!
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why is this inappropriate?
Heather: You have "broadening my horizons" as something you want to do. Well, learning more about a 3 step filtration system was just that. Or did you already know about the 3 filtration system?
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why is this inappropriate?
Hey Sher: on your profile you have a list of things that bug you. And one of them is whiners. Sounds like you are whining as I just gave facts and a place to find out more. Would you prefer to be ignorant of the facts?
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I agree with you Heather. Spam stay away please.
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I agree with you Heather. Spam stay away please.
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