One of the questions that often comes up in relation to Earthships is why do they use flush toilets instead of composting toilets. The design for the Waiheke earthship intends to follow the Earthship approach to sewage treatment and recycle used water (grey water) through interior plant filters/ botanical cells which is then used for flushing toilets and then treated using a Simple Wastewater Solutions vermi-composting wastewater system. This wastewater system is an advancement over a standard septic tank as all the toilet wastewater goes into an exterior solid waste digestor where the worms turn it to compost. Instead of having to pump out a septic tank every few years (and send the sludge to landfill), the end result is nutrient rich compost which can be used in the orchard. The Simple Wastewater Solutions system also involves a series of exterior plant filters which further treats the wastewater by filtering it and transforming it to an aerobic state by using natural processes instead of electric air pumps which most conventional onsite waste water treatment systems require.
Simple Wastwater Solutions digestor and plant filters at Ivan Kitson’s, Waiheke Island
The Simple Wastewater Solution system has been approved within the resource consent for the Waiheke earthship as its an approved wastewater system in Auckland as long as you have sufficient land area to absorb the wastewater. The internal workings of recycling the greywater to flush the toilets falls under the building consent process rather than resource consent so this still has yet to be approved.
So why not just have a composting toilet? Composting toilets require a well ventilated chamber under the toilet that you can access to extract the compost and for maintenance purposes. Given that earthships are built on the ground/ concrete pad, into a slope and/or surrounded by earth this is not usually practical, unless your composting toilet is in a separate out-house or you have your toilet raised high off the ground above the chamber and get the compost out from the top in which case you have to carry it though your house to remove it.
Thats wonderful to see that councils are not allowing themselves to become so bound up with legislation.
Happenings like the Earthship consent and now the waste water, must go some way to reclaiming our No 8 wire society that in the past has encourged NZers to become innovators and leaders in so many areas and of recent seemly to stop all creative building especially.
Please keep up the push and the pasting of of what stages and hurdles you surmount 🙂
That’s an excellent idea! I think Reynolds said that Earthships have standard flush toilets as it will appeal to more people in the mainstream population, make it easier to accept the overall concept. Myself I have been thinking about the septic tank element of Earthships for awhile and it really does miss out on several excellent options for black water use. The best I’ve come up with is flushing the water into a bio-digester rather than a septic tank in order to harvest the gas generated( don’t worry it doesn’t smell)and running it back to the cooker in the Earthship. Then if you don’t have to worry about the availability of pressurised gas cylinders when peak oil stuff happens. As a bonus you still get to harvest the slurry for your orchard. Free fuel for cooking etc. Free composting material. Zero waste. Closes the loop on the Earthships external inputs.