living machines

permed at nor.com.au permed at nor.com.au
Mon Dec 17 21:12:29 EST 2001


>Robyn,
>Can you elaborate more on your system and the load it takes?
>Here in Indiana a number of constructed wetlands have been approved under
>experimental permit, but they have still required the full installation of
>septic tank and absorption field in addition to reed beds. This is
>prohibitive for most people to afford. I know of no Dept. of Health approved
>situation where grey water is separated.

I have 2 separate systems, 
1. for the railway carriages (accommodation) which has composting toilet 
and reedbed treatment for greywater (plus excess urine from the toilet). 
This is a domestic-scale system designed for a 4-person household. The 
reedbed is 8 square meters surface area (2m per person) and deals with 
approx 150-200 litres of waste water per day. From the reed beds the 
treated wastewater feeds into a small holding pond which has floating 
waterplants (azolla, duckweed & water celery) which we scoup out and feed 
to the adjacent chickens (the chooks eat the water weeds then lay eggs, 
we eat the eggs and go to the loo and it all goes through the system 
again). The volume of treated wastewater just keeps the pond full and 
there hasn't been surplus to re-use in gardens etc as the pond has a 
natural clay bottom so some water infiltrates and some is lost to 
evaporation.
When the post-grad student analysed results from the system (we took 
daily samples from various stages of the whole process) he asked us if we 
had a lot of people around on a particular date - we had a party that day 
with 40 folks peeing in the compost loo and what was interesting was that 
the shock-loading took over 2 weeks to gradually work through the system 
which meant there was no big nutrient shock-load going into the pond.

2. the other system is for the education centre building and treats black 
water from a flush toilet and greywater from handbasin and the commercial 
kitchen. The use and volume is variable with activities at the centre. 
After settling the solids in a 1000 liter septic tank the liquids flow 
through the reed beds (40 square meters surface area) then the treated 
wastewater flows from the reedbeds into an open holding pond which has a 
series of 8 flowforms - gets pumped for about 3 hours a day through the 
flow forms. Once again due to the low volume of water use and natural 
clay pond bottom we don't have surplus water to use for irrigation.

NOTE: the health department does not issue permits for wetland treated 
wastewater to go into such holding ponds on private properties - we had a 
special permit due to the experimental nature of the system and because 
as a Pc education centre they felt we would monitor the system properly. 
Most domestic treatment systems of this kind that have been installed and 
approved in recent years have a holding tank after the reedbed with a 
submerged pump to send the water through a drip irrigation system (buried 
10cm or 4inches under the soil) or through transpiration beds.
The health dept is naturally paranoid about pathogens and want to 
minimise/eliminate potential for people contact with the treated waste 
water - they are particularly fearful of litigation if anyone gets sick 
from something they approve.

Treating waste responsibly is not a cheap or easy process and I think 
people have been 'spoiled' with heavily subsidised centralised town 
treatment systems and the cheap but woefully inadequate septic tanks on 
rural properties. Contamination from human waste is a big polluter of our 
river systems and ground waters and as populations increase so do the 
problems without adequate treatment.

One of these days I'll find time to put up a page on the web site with 
diagrams and photos of these systems.
Robyn


Djanbung Gardens Permaculture Education Centre
home to: 
Permaculture Education
ERDA Institute Trust
Nimbin Eco-Village Project Office
Robyn Francis - permaculture designer & educator
PO Box 379, Nimbin NSW 2480 Australia
Ph 02-6689 1755 Fax 02-6689 1225
permed at nor.com.au  www.earthwise.org.au




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