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Reverse Osmosis Water Filtration

Reverse Osmosis Water Filtration

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.

Read more: Home, Health & Safety

Excerpted from the Real Goods Solar Living Source Book,edited by Doug Pratt and executive editor John Schaeffer.Copyright (c) 1999, Real Goods. Reprinted by permsision of Chelsea Green Publishing Company and Real Goods.
Excerpted from Real Goods Solar Living Source Book,edited by Doug Pratt and executive editor John Schaeffer.

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Annie B. Bond

Annie is a renowned expert in non-toxic and green living. She was named one of the top 20 environmental leaders by Body and Soul Magazine and "the foremost expert on green living." - Body & Soul Magazine, 2009. Learn Annie's latest eco-friendly news on, a website dedicated to healthy and green living.

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10:40PM PDT on Jul 9, 2014

This is such a good read. People must realize about the kind of water they are using or drinking. With information on Revese Osmosis, they can have a good start!

4:14PM PDT on Jul 24, 2013

It looks like there is a better way to remove fluoride from the water.
For washing dishes and brushing teeth, the reverse osmosis system works just fine because it dose remove chlorine.However, for drinking water, it needs to leave in beneficial minerals so the body gets exactly what it needs.

5:03AM PDT on Jun 4, 2012

I really wish there was a better way to get fluoride and other toxins out of water than RO. It wastes so much water

11:32AM PDT on Jun 3, 2012

An interesting post - I do not filter my tap water and unless I am away from the UK I do not buy bottled water.

12:38AM PDT on May 1, 2012

Thanks for the article.

2:46AM PDT on Apr 20, 2012

Thank you for the post.

2:43AM PDT on Apr 20, 2012

Anne, Thank You. Excellent.

9:39PM PST on Jan 21, 2011

Thanks for the info.

4:14AM PDT on Jul 28, 2010

RO sounds like a life saver, but one of the substances that are highly pollute is chlorine, which you find everywhere in this world. Maybe we should forbid people to drink tap water. water damage restoration is another interesting process you should consider.

10:42PM PST on Nov 23, 2008

I'm excitedly waiting all the changes in technology and availability of vehicles in the near future!!!


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Disclaimer: The views expressed above are solely those of the author and may not reflect those of
Care2, Inc., its employees or advertisers.

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