Worms Eat My Poop: Building a Vermiculture Compost Toilet

| 1/12/2015 9:45:00 AM

Tags: compost toilets, vermiculture, Kiko Denzer, Oregon,

A compost toilet can be as easy as pooping in a bucket, but a bucket system means another weekly chore emptying and managing smelly buckets. When I moved into my cabin in the woods 20 years ago, I started out with a bucket that I just emptied direct into a hole-in-the-ground, but after I got comfortably moved in, I started thinking about a pooper even mom would be happy using.

Mexican friends (also permaculture teachers: see Proyecto San Isidro), recommended building my toilet over a divided concrete vault, and separating liquids from solids. The separator was just a funnel placed low at the front of the seat, where it would catch and divert urine from any (seated) male or female.

harvest time 

We pee more than we poop. In a compost pile, every unit of high-nitrogen pee needs 40 times as much high-carbon (woody/fibrous) material to keep the little compost bugs happy and making sweet-smelling compost. So keeping pee out of a system reduces stink and volume.

I was mulling things over when another permaculture acquaintance, a brilliant guy named Tom Watson (developer of the low-water Watson Wick septic system), affirmed that compost worms would be just as happy eating my poop as my kitchen scraps.

Letting the worms deal with my waste sounded good. The Mexican design specified an above-ground concrete vault with steps up to the seat, but I was building in an existing building, so I had to keep it low. I dug down, pouring a 2-chamber concrete box, topped with cedar 2-by-6s. I hinged one board to make a seat (for comfort's sake, it needed to be 7-1/2 inches wide). I covered the bottom of the working chamber with a drainage layer of coarse woody stuff (sticks, big wood chips, etc.). Then I added a funnel below the front of the seat, a pipe to a 5-gallon bucket outside, and some worms. Done! (here are some pictures of a vermicomposting toilet)

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