permaculture

[Toby Hemenway <hemenway@jeffnet.org>]

Stephan Leimroth wrote:

>i'm looking for ideas for a grey water filtration system adequate enough
>to handle at most >120 gallons (450 l) per week.

Stephen: A gravel and sand filter won't remove the dissolved contaminants
(soaps, etc), but only the hair and other solids. You really need living
elements to process the organic and inorganic compounds dissolved in the
greywater. I'd recommend a wood-chip filled mulch basin that feeds some
plants, or a planted bog. A very simple system is just a 20- or 55-gallon
drum that empties (all at once via a siphon, if possible) into a heavily
mulched bed around some trees. If the outlet is a hose, you can move the
outlet every few days to a new bed. Greywater is not very unsanitary unless
it's been stored for a few days; then nasty bacteria build up, so you don't
want a big holding tank. Usually it can just go right onto a pile of mulch
or some other absorbant.  Art Ludwig has a lot of great information at his
website, http://home.sprynet.com/sprynet/odesign/home.html, and you might
want to get his books before proceeding. I wouldn't recommend trying to
make drinking water; that requires about 4 layers of treatment and if
something fails, you could get very sick (the treatment could make the
water worse if it's not running right). But John Todd's work on Living
Machines will show you some fine ideas in that direction, if you want to
track that down. The Permaculture Activist
(http://sunsite.unc.edu/pc-activist) has good articles on greywater systems
and constructed wetlands in issues 37 and 32, respectively.

Good luck!
Toby Hemenway