The above graphic is from a book that does not stink: The Humanure Handbook. Here’s a pdf version of this potential soution to water overuse.

As author Joseph Jenkins notes, “a single person using a Clivus (pronounced Clee-vus)
Multrum [specific type of composting toilet] will produce 40 kg (88 lbs) of compost per year while refraining from polluting 25,000 liters (6,604 gallons) of water annually.”

Make compost + save water = what’s not to like, right?

For starters, commercial models are way too expensive: often $1000+ per toilet.

Jenkins’ 5-gallon-bucket-of-excrement-and-sawdust method sounds like it works (plans here), but that’s rather labor intensive and may be difficult to convince your less-radicalized cohabitants to adopt. Septic systems are notoriously bad (both on your wallet and the environment), and alternatives like the pumice wick may or may not actually work.

What i want to do by end of year is create the following system:
-Normal high-efficiency flush toilets in house
-Solar-powerered pump(s) push blackwater to ‘cooking’ tank, to which household scraps are added (help increase carbon content to hit right carbon-nitrogen ratio) and water is allowed to boil off (prevent anaerobic environment from occurring for too long)
-Arduino regulates temperature via solar parabola and fan/vent at height (avoid smell) to keep solids at 113fahrenheit for 3 days –> kills all nasty bacteria to EPA standard by letting thermophilic bacteria dominate (see jenkins’ book p. 150)
-Resulting 3-day-old former poop/paper/urine then aged for a week or 2 in your normal compost pile to avoid colonization by salmonella or other nasties. (Poop should be smell-free at this point)
-Optionally, you can run this as a solar still to recapture (and even drink?) the water you distill off!

I estimate one can build this for <$500 parts and 40 hours time. Am I off the deep end, or does this just maybe make sense? Of course, it goes without saying that you should not try this without being prepared for the potentially malodorous consequences!