Site location: San Francisco, CA

Overview of the composting toilet

Goals: To save water and create compost.

 Site description: This is in a small house in Noe Valley (San Francisco). The toilet is used by two adults.

Composting toilet commode replaces flush toilet. Toilet seat is on top of a 5 gallons bucket. Chambers containing the cover material located on the sides.

Composting toilet commode replaces flush toilet. Toilet seat is on top of a 5 gallons bucket. Chambers containing the cover material located on the sides.

 System description:

For our composting toilet we follow the method outlined by Joseph Jenkins in, The Humanure Handbook, meaning we do not separate liquids and solids. For our bathroom I built a simple plywood commode that houses a five-gallon bucket, with a compartment on either side for cover material and tp. The cover material that we use is the “Early Vineyard Mulch” from the Sonoma County dump, mixed with scrap paper and junk mail that we shred in our Fellowes MS-450Cs Microshredder.

Composting cage used to compost humanure.

Composting cage used to compost humanure.

In a shaded corner of our back yard I have constructed a composting cage. It consists of some industrial shelving grids lashed together with wire. The cage is divided into two sections, each roughly 4 feet deep, 4 feet high, and 3 feet wide. I have made a hinged top to cover the active side of the cage.

 

 

 

Cover material

Cover material

Between my wife and I we usually fill 2 buckets a week, which I cap and store under a tarp in the back yard. When we have accumulated 8 buckets I initiate what we call  “the big dump,” which entails my emptying the buckets into the composting cage and covering everything over with a layer of straw. Within a few days the temperature usually hits about 120F, then slowly comes back down to about 80F after 4 weeks. After a year I close off the active side of the composter. The material on the other side of the composter is ready to be harvested, with the stuff on top being a year old, and the stuff on the bottom being two years old.

So far we have been doing this project for two years, and have one year’s worth of composted humanure to show for it. We used it, among other places, in a planter box that runs along the length of our front fence, right on the sidewalk, where we planted tomatoes and beans, both of which are growing insanely well in the rich soil.”

Thank you Larry G. for the photos and text describing your system.

Specifications and NotesThis toilet combines urine and feces. It uses more cover material to soak up the urine than a urine-diverting toilet would use.

Maintenance and trouble shooting: Weekly switching of buckets, monthly dumping buckets into compost and cleaning buckets.