Water

Published on March 29th, 2009 | by Tina Casey

3

Sink-to-Yard Graywater Retrofit Could Make Desert Bloom

March 29th, 2009 by  


sink-to-garden.Researchers at New Mexico State University are testing a relatively inexpensive plumbing retrofit that could help buildings capture relatively clean graywater from plumbing before it hits the sewers, and reuse it onsite for outdoor watering.  It’s a green four-for-one: the NMSU graywater system conserves water, relieves sewer systems of excess flow, fosters tree growth to cool buildings, and reduces stormwater runoff by improving soil and vegetation.

Graywater Recycling is the Wave of the Future

Graywater generally refers to water from buildings that does not come from toilets (that’s considered blackwater).  Graywater comes from bathroom sinks, showers, bathtubs, dishwashing machines, clothes washers, and practically any other fixture into which humans do not normally relieve themselves.

For some purposes, kitchen sinks are considered blackwater sources because of the grease and meat scraps they contribute to the wastewater flow.  If you use cloth diapers and wash them at home, your laundry machine may also be considered a blackwater source.

Graywater Recycling in New Buildings

New green buildings ideally include a customized system for separating graywater from blackwater.  Graywater recycling systems also are perfect for low-income housing because they help keep operating and utility costs down.  In urban areas, recycled graywater can be used to flush toilets rather than for grounds keeping.

Designers are also beginning to explore the concept of plumbing fixutres that have built-in graywater recycling capabilities, such as a clothes washer that supplies used water directly to a toilet.

Graywater Recycling in Existing Buildings

Installing a graywater recycling system in an existing building can involve an extensive plumbing retrofit, which is beyond the financial reach of many individual households.  NMSU has an answer for that.  Their research is focused on a remote-control system that can be installed in existing plumbing.  They are working with a company called Aquaverde, Inc., that has developed a graywater recycling system that uses radio signals to detect activity in blackwater fixtures.  When the blackwater fixtures are inactive, a valve diverts graywater to a collection tank.  When the sensors dectect blackwater activity, (for NMSU’s purposes, kitchen sinks are included) the flow goes to the sewer line.

Graywater Recycling – Problem Solved?

If the Aquaverde system proves cost-effective, it could potentially put graywater recycling in the hands of millions of ordinary homeowners.  The system does require energy to run a pump, which could be offset individually by simple energy conservation measures, or with solar or other alternative power.  The increased energy demand could also be offset on a macro level, taking into account the reduced demand on water supply and sewage treatment systems in a given area.

Energy and plumbing costs are not the only limitation, though.  A truly mass shift toward onsite graywater recycling would require some additional adjustments – and that’s a good thing.

Building owners and occupants would need to pay more attention to everything they pour down a drain – after all, it’s going to end up in their community, not miles away .  Graywater recyclers would need to focus more of their purchasing on eco-safe detergents and household cleansers, natural shampoos and other personal grooming products, and chemical-free foods.  We could also see more attention on keeping medications and do-it-yourself products out of building drains- and that’s another good thing.

Image: merelymel13 at flickr.






Complete our 2017 CleanTechnica Reader Survey — have your opinions, preferences, and deepest wishes heard.

Check out our 93-page EV report, based on over 2,000 surveys collected from EV drivers in 49 of 50 US states, 26 European countries, and 9 Canadian provinces.

Tags: , , , ,


About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



  • Pingback: Electric Mole Takes a Bite Out of Energy Costs, with Help from Solar Power : CleanTechnica()

  • One area that most people forget about going green is in the Laundry Room! Families across America buy 6 Billion USD of laundry detergent every year. Concervatively, that is enough to fill 126,000 semi trucks parked bumber to bumber from Vancouver to Los Angeles fully loaded with 20 tons of detergent each. This is what gets added to the water in washing machines which on average dumps about 25-30 gallons of chemically loaded, polluted water into our environmrnt per load. That amounts to approximately 330 Billion gallons of polluted water every year.

    But now there are ways to do your laundry without dumping any polluted water into the water ways! I could tell you how to say good-bye to the continual expenses of buying laundry detergent, fabric softner, bleach and paying for extra heating bills from Hot Water and still get your clothes just as clean. For every 100 families that choose the new method that means that 1.152 million gallons of detergent-water slurry WILL NOT ENTER our waterways. 2,400 empty boxes or containers will not have been stuffed into landfills and tons of products will not have been shipped (consuming fuel) from their manufacturer to your store! And no hot water will have been heated! You could water your grass from the water flushed from your washer! If you want more infomation on how you can do your part and join the Suds Free Revolution please email me at ekoliver@laundryplus.com

  • One area that most people forget about going green is in the Laundry Room! Families across America buy 6 Billion USD of laundry detergent every year. Concervatively, that is enough to fill 126,000 semi trucks parked bumber to bumber from Vancouver to Los Angeles fully loaded with 20 tons of detergent each. This is what gets added to the water in washing machines which on average dumps about 25-30 gallons of chemically loaded, polluted water into our environmrnt per load. That amounts to approximately 330 Billion gallons of polluted water every year.

    But now there are ways to do your laundry without dumping any polluted water into the water ways! I could tell you how to say good-bye to the continual expenses of buying laundry detergent, fabric softner, bleach and paying for extra heating bills from Hot Water and still get your clothes just as clean. For every 100 families that choose the new method that means that 1.152 million gallons of detergent-water slurry WILL NOT ENTER our waterways. 2,400 empty boxes or containers will not have been stuffed into landfills and tons of products will not have been shipped (consuming fuel) from their manufacturer to your store! And no hot water will have been heated! You could water your grass from the water flushed from your washer! If you want more infomation on how you can do your part and join the Suds Free Revolution please email me at ekoliver@laundryplus.com

Back to Top ↑