Seeing the potential in 'greywater'

from wickedlocal.com

By Judy Otto/Special to the Minuteman
Thu Apr 09, 2009, 06:05 AM EDT

LEXINGTON - Lexington’s new Department of Public Works building will be using a gravity-fed greywater system to fill the sweeper trucks and wash vehicles. Rainwater roof runoff would ordinarily either seep into the aquifer or flow down a storm drain and eventually into the ocean.

There are other kinds of greywater and other uses, although most of them are uncommon in Massachusetts.

If you’ve looked up “greywater” on the Internet, you may have found more information that you know what to do with.

My recent search yielded 81,200 Google entries for “greywater systems.” Among the first 100, most entries provided information on use of greywater to irrigate gardens, some talked about composting toilets, and a few elaborated on greywater to flush toilets.

Whether from runoff or household, greywater is an important sustainable resource for several reasons.

In an average household, each person will use 80-100 gallons of water per day. The highest use, 26 percent, is used to flush the toilet.

· 20 percent: showers and baths

· 15 percent: kitchen and bathroom faucets

· 3 percent: cleaning and washing dishes

· 23 percent: laundry room

· 13 percent: leaks

Greywater is typically defined as domestic wastewater that does not contain human waste, such as tub, shower, or washing machine water.

Water from toilet flushing is called blackwater and unless you live in Thailand, where night soil is used as a fertilizer, blackwater must go to a treatment plant.

Greywater has contaminants, too, the worst of which are certain commercial products such as cleaning products, shampoos, and cosmetics.

Used water from kitchen sinks and dishwashers is excluded because too much soap, oils, fats, particulates, and food pieces clog pipes.

Irrigation of non-food plants is the most common use of greywater, but this is rarely employed in Massachusetts, and is subject to state regulations.

An even better, and year-round, use of greywater is in flushing toilets. Flushing with greywater is where most of the savings can be realized, not just in terms of monetary cost, but also in saving gallons of pristine water that is flushed down the toilet in order to carry away much smaller amounts of human waste.

In states where water is scarcer than in Massachusetts, use of such systems is becoming more common. Some European countries have been flushing with greywater for 20 or more years.

For more information on earthship greywater systems, click here: sewage.earthship.net

In Massachusetts, you’d need a special permit to pilot such a system. But in Tucson, such plumbing for greywater systems will be required in all new homes built after mid-2010.

All this information, although interesting, may not be immediately useful unless we advocate for greywater use, apply for permits, and install systems in our homes and buildings. 

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