Our lot is too small to have a septic field, so we have a 1000 gallon holding tank for our greywater waste and a composting toilet. Does anyone know if its ok/safe/a good idea, to periodically, in good weather, to open the lid of the holding tank a little for the purposes of allowing some of the greywater to evaporate? Not sure if it would even make a dent but given the condensation on the underside of the lids when we take them off to check levels there's obviously some evaporation going on.
That is a tough gig. If you observe how a garden pond evaporates you will notice it is slow.
I think that idea is doomed.
What regulations are there in the area?
What does other small block owners near you do?
What weather conditions do you have?
Guide to treatment
But these all require discharge to ground in the end.
Because of the volumes involved grey water retension may be a headache.
John Daley Bendigo, Australia
The Enemy of progress is the hope of a perfect plan
What is your climate? And do you have a little land and plant area?
If it is an arid climate, and if you have an area of plants, it would be great if you could use the greywater for irrigation. I use my greywater for irrigation, and at the school I lived at for over 20 years, we did, a very simple system. We just had the greywater daylight out from buried pipes to narrow little irrigation canals along a lot of trees. The willows love it, but the apricots, pears and apples also seem to love it.
The willows get water from the bathing block so it has lots of soap, laundry detergent, and god-knows-what "products" our 60-100 teenagers use, but the willows don't seem to mind.
The fruit trees get water from the school kitchen and dining hall dish pit, so the water has comparatively less soap and detergent, and a lot more food particles making it rich. We made a wood chip filter to filter out the food particles, which seemed like a great thing but then we had to destroy it for kitchen expansion construction. Otherwise in warm weather the canal downhill from the kitchen sometimes stank.
I was greatly inspired and encouraged by Art Ludwig's book about greywater, and his website, Oasis Designs. He explains how topsoil exposed to the air has such a lively ecosystem in it that "daylighting" your greywater can be much less trouble and less smelly work than trying to filter it into underground perforated pipes. We don't have any regulations constraining us, and we were already doing that, so it was good encouragement.
Storing greywater, even for a day or two, and even when it doesn't seem very dirty, tends to make it smell something awful.
Works at a residential alternative high school in the Himalayas SECMOL.org . "Back home" is Cape Cod, E Coast USA.