Whilst I don't Claim this to be a Completely Self-Sufficient city idea, I do believe it would be very efficient.

The Idea is fairly simple:

The effluent water from a large housing estate is treated until it is at an irrigation standard of quality. (much cheaper than treating it to drinking standard, and with none of the stigma.)

The recycled water is used to irrigate a plantation. (Fruit trees or orchids).

When the trees are pruned, the cuttings can be used to produce biomass fuel and electricity.

The sewerage from the housing estate can also be used to produce biofuels.

The wastes from the biomass plants will then be returned to the plantation as a rich fertiliser.

The Farm and biomass plants would be a rich source of employment for the people living in the housing estate, and much energy and water would be saved.

Thoughts?
-- Domser, Jul 11 2009

A nice idea, but the trouble is in the details. Some questions to get started... please define "irrigation standard" water (amount of bacteria per litre?)...Would the treated water come from existing processors or would new construction be required to meet standards?... what about non-desirable residue (from the water) building up in the soil?... What will be used to augment tree cuttings to produce biomass fuel? (you're going to need a lot to make it meaningful)... the people in the housing estate are going to need more money than they get from being employed by the farm...
-- Gamma48, Jul 12 2009


Fair call. New construction would be required to treat the effluent, however, these would be far cheaper than purifing the water for drinking. I'm not sure about the amount of bacteria per litre, but untreated river water is usually used for irrigation.

As for the tree cuttings, quite a substansial amount of wood is pruned from the trees every year, and, on a large plantation, the amount of wood collected would be large. There are biomass plants in operation which anaerobically digest wood to fuels such as methane.

As for the employment factor, I told you that it wasn't a completly self sufficient city. Water and Power would need to be brought in, and people would have to seek employment elsewhere. The idea is to reduce impact.
-- Domser, Jul 12 2009


//not sure about the amount of bacteria//
The concern is human bacteria. But for storm runoff you usually only have to worry about dissolved pesticides and fertilizers.

I like the idea of a neighbourhood treatment plant though.
-- FlyingToaster, Jul 12 2009


Baked and baking for 30-odd years worldwide. Google permaculture. However I won't m-f-d because you clearly came up with this on your own. It might excite you to find a global movement of people who think like this.

One notable example is Village Homes in Davis, California.
-- BunsenHoneydew, Jul 12 2009


I like the concept, but I think your system is a bit wasteful. For example, if one uses appropriate soaps, greywater (wastewater except that from the toilet) can be safely used to water food-producing trees and bushes. No need for a treatment plant, just some filters and pipes. I'm not sure that sewage->biofuel->fertilizer would be most beneficial; running a biofuel plant requires a lot of energy. Sewage->fertilizer via high-heat composting might provide more bang for your buck. Still, bun for systems thinking.
-- ryokan, Jul 16 2009


This is remarkably similar to how most rural life existed throughout human history.

"Unsustainble" living practices are a rather new, ~20th century thing.
-- sophocles, Jul 16 2009



random, halfbakery