Monday, April 14, 2008
Greyt Detergents for Grey Water Systems
It’s time to turn the illegal valve to use my grey water.
Soap is soap, and most laundry detergents appear to be just the same old detergent. This is fine, unless you have a grey water system designed to irrigate your favorite petunias or roses with the used water from your washing machine. Plain soap, which is made from stuff like animal fat and lye (wood ash), doesn't stop minerals in the wash water from depositing a dirty "smog" on your favorite pure-white undies. So, over forty years ago, Procter & Gamble invented Tide as the first heavy-duty synthetic laundry detergent.
Detergents, fabricated from a variety of chemicals in addition to soap, are engineered to enhance the soap's cleaning capability and avoid graying those undies. But, alas for grey water users, chemicals in detergents are selected with only their clothes-washing capabilities in mind, and with no thought for a thirsty root's sensitivities.
To choose the best detergent for a grey water system, you'll have to read product labels. First, look for the most important element to avoid: sodium. Unfortunately, the amount of sodium in most detergents is impossible to ascertain, and they won't tell you on the 800-consumer phone line because "It's proprietary." As a rule, popular liquid concentrates have much less sodium than powdered detergents, which use cheap sodium-based compounds to bulk up the product.
Next, look for the words boron, borate or Boroteam. Boron rarely kills plants, but it will cause an ugly leaf-margin burn, and can be a real problem with alkaline soils in desert areas. Worse still, once boron is added to soil, it is not easily leached out. So skip all detergents with boron.
Phosphates chemically inactivate calcium, magnesium, iron and manganese without making a precipitate (depositing a grimy "smog" on cloth). These are the chemicals blamed in the 1970s for "ruining" lakes and rivers (it's since been learned that laundry phosphates weren't always the significant culprit). Actually, phosphates are a great ingredient for a grey water system because roots utilize them like a fertilizer. Since a grey water system is managed for the improved growth of the plants, buy a high-phosphate detergent—if you can find one (many states have banned in as an ingredient). Because you'll be monitoring your grey water system, you can make sure phosphates aren't leaching off your property to turn rivers or lakes green.
Finally, watch out for chlorine, which in its concentrated form is a very caustic, toxic and deadly chemical. The amounts of chlorine in detergents are actually quite low, but the prudent gardener will avoid this chemical altogether. (However, I have used chlorine bleach on occasion in the laundry and to remove stains in the bathtub, and have yet to see any visible consequences in my landscape.)
A quick survey of any supermarket will soon reveal a plethora of detergents either useless for grey water or, at best, ambiguously labeled. What's a lawless grey-water user to do? (It's still illegal in most places to use grey water.) I shop for a more “Earth-friendly” detergent but get the full scoop on boron, sodium, and chlorine.
For the latest on grey water developments, see the web site of the Guru of Grey Water, Art Ludwig: http://www.oasisdesign.net/greywater/
Please post a comment - I want to know what you think. Are you an illegal grey water user?
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NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert