Greywater
Greywater is the water from sinks, washing dishes, showering, and
so on. It does not contain nearly as many nutrients as humanure or
urine, but it can contain some pathogens. Greywater should be treated
with reasonable caution. It can also contain food scraps which might
attract rodents and other animals, or produce smells. To avoid these
problems, it’s good to get the water under the soil as fast
as possible.
Because it can contain pathogens, it should not be applied directly
to vegetables which will be eaten. However, it can be applied to trees
or berry bushes, which is an excellent way of reusing the nutrients
and water. Greywater should not be poured into streams or bodies of
water. Greywater pits should be built a safe distance from water sources
like streams and wells, at least 30 m depending on soil conditions.
Depending on how much greywater you produce, you can pour at least
part of it into the top of your compost pile, assuming that this won’t
make the compost too wet. That is one of the best ways to deal with
it.
In cold climates, you may have trouble with greywater freezing in
the winter, or snow covering the greywater pit. If possible, put the
pit behind a windbreak (so that the prevailing winds will not drift
snow over top of it) and pour the water in. The heat from washwater,
and the heat of the soil should help except in extremely cold areas,
in which case you will simply have to wait for the water to thaw in
spring. The branching system described below is not ideal for very
cold climates in winter.
Greywater Pit
The simplest way to get rid of greywater, and one very appropriate
for camping or wilderness situations, is to dig a pit about 1 foot
wide by 2 feet deep. You can put criss-crossed sticks and long grasses
over the top to act as a grease trap, which will filter out some grease
and food scraps. You can then regularly burn the grasses in your fire.
you can build a larger pit as well, such as one made out of a drum
with large holes punched in it, or the bottom cut out. The barrel
can be partly filled with stones and gravel, which prevent access
by rodents.
The downside of the simple pit system is that the one area receives
a lot of water and nutrients, maybe too much, while other areas aren’t
getting enough. You can improvise a branching greywater system to
distribute greywater to a larger area, such as an orchard.
Branching System
This system works using a downhill grade. Water is channelled from
the house, washing site or dump site, to mulch covered troughs.
The channels may be simple improvised, shallow trenches in the surface,
depending on conditions. Better yet, they may be covered, filled in
with gravel and small stones, or replaced by pipes. These channels
must slope downhill continuously, or the water will back up or pool.
The destinations are shallow depressions or trenches full of mulch.
The water may go directly into the mulch, or into a gravel filled
container, which then releases the water into the mulch. Alternately,
water could be poured directly into the gravel bucket, as an improved
pit system.
Greywater Notes
Create an Oasis with Greywater: Your Complete Guide to Managing Greywater
in the Landscape, by Art Ludwig. You can visit the author’s
site at www.oasisdesign.net
The Humanure Handbook, by Joseph Jenkins
Fieldbook for Canadian Scouting, Boy Scouts of Canada, 1986
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