It’s not obscure! Composting toilets use less resources than AWTS. What you can do with grey water varies between sites and councils. There are numerous limitations on above ground disposal in any instance.
For AWTS vs conventional septic and grease trap systems in a water blessed location.
We collect 500kl roof water pa. Of this we consume domestically less than 100kl pa. It would be great if Gordon could have some of the excess. The whole of the grey and black water goes back to our ecosystem through sub soil trenches from our septic or grease trap. It is not wasted environmentally.
True it is not recycled for domestic reuse but neither is the waste water from an AWTS. If we had an AWTS we would still need sub soil disposal. That’s what the council requires for our site. The outcome for either wet system (septic or AWTS) is the same for our circumstance. There is no additional water reuse benefit from an AWTS.
An AWTS would also consume approx 800kWhr of electrical power pa. I don’t know what this is in carbon equivalents. It would add costs for servicing which also has a carbon footprint, and consume even more resources. IE all additional inputs/waste that is not recovered! A crude estimate puts the cost of the water we might recover for reuse at $10,000 per mega litre. That’s for secondary treatment standard only.
Several of our neighbours have AWTS. They are on one acre blocks and can only dispose of their waste water sub soil.
A composting toilet system would be great in that it would save having to pay for sludge pump out. A cost common to both septic and AWTS operation.
As per my previous post the core discussion on the relative merits of different approaches to domestic waste water management and the efficiency of each option deserves a separate topic.