When I last wrote about composting toilets, I suggested that " if we are truly going to develop a zero waste society and protect our water resources, we are going to have to start thinking about dealing with all of our wastes and not keep flushing some of them down the pipe." Commenters didn't believe it: "No one will want this inside their house. I know this, because I still have a few teeth in my head and a few friends in town." and "Composting toilets are NEVER going to make it into the main stream market. Debating it is silly."
I wish I had known then about the C.K Choi building in Vancouver, British Columbia; it is a 34,000 square foot office building by Eva Matsusaki that is completely off-pipe, using Clivus Multrum composting toilets, since 1996.From City Farmer, we learn that "There are a total of 5 Clivus Multrum Model M28 Composters at the Choi Building...with ten flushless toilets and, in addition, several flushless, trapless ventilated urinals attached to them. Each of these Clivus Composters has an annually user capacity rated at 45,000 visits. Therefore, the total annual rated capacity for the Clivus systems there is 225,000 visits. All of the Choi building's washwater (greywater) is processed on-site separately."
Justin at Meta-efficient writes that " The system is maintained and emptied by the Clivus Multrum company through a service contract. Every day the university maintenance staff wipes down the toilets and adds a can of wood chips or bark mulch to each toilet. Every six months, the compost (which no longer resembles feces) is removed from the system and used as a fertilizer" and concludes:
"What this example clearly shows is that modern buildings can do quite well without a connection to a municipal sewage system. The maintaining the building’s composting system is probably less overall than a building with flushing toilets." ::Metaefficient
It also shows that systems can be set up so that composting toilets are almost as care-free as conventional ones, if one uses an outside service to take it away. This is how it worked for centuries in China and Japan, where people came and removed the "night-soil"; with a modern composter like a Clivus Multrum it need only be serviced every six months.
It shows that we can design urban buildings that are off-grid but also off-pipe. The current system of installing huge concrete pipes to carry our crap into someone else's backyard may be convenient but isn't sustainable.