Vermicomposting Human Waste
Project title: Vermicomposting Human Waste (Composting Human Manure with Worms)
This project goal is to determine the efficacy of vermicomposting human excrement. These results should encourage UBC to consider retrofitting the CK Choi composting toilet to facilitate vermicomposting and establish the building as a research site with the greater objective of including vermicomposting as an approved process under the Organic Matter Recycling Regulation (OMRR).
Composting toilets are marketed and sold as waterless human waste treatment systems. The overall goal of most compost toilet manufacturers is to decompose human waste to the point that it can be safely disposed on-site. Marketing information from compost toilet manufacturers indicates that composted end-products (both liquids and solids) are suitable for on-site disposal / use. As such, they present attractive solutions for a wide variety of sites including the developing world where water is scarce, green buildings where sustainable alternatives are showcased, and sites where septic field construction isn’t practical.
However, in reality, composting toilets do not heat to thermophilic temperatures and do not employ a proven pathogen reduction mechanism. Manufacturers claim to accomplish these goals with mesophilic (moderate) temperatures and competition from benign microbes. These claims are not supported in academic and technical literature; on the contrary, resistant pathogens such as viruses and hookworms have been shown to survive long periods of time in cool saturated compost piles.
Composting toilet end-product disposal is regulated under OMRR in BC and results indicate that it is not safe to discharge liquid or solid leachate into the environment without further processing treatment, or transport to an approved facility.
UBC purchased and installed Clivus Multrum composting toilets into the CK Choi building in 1996. Blackwater has been released into the environment surrounding the CK Choi building since its construction. I surveyed solid end-product and blackwater in 2011 and found extremely high levels of E.coli (pathogen indicator organism) in both. The toilets were temporarily shut down, liquids diverted to sewer and consultants hired to recommend options. They are suggesting removal of the composting toilet system and replacement with a standard sewer system or water-based system.
The majority of humans on the planet do not flush their waste with water. Because of this, it is important to investigate a waterless toilet system at UBC. Vermicomposting is emerging as a viable waterless, low temperature, human waste treatment system that has proven successful in pathogen destruction. However, very little research exists on the application, efficacy, and reliability of vermicomposting in the toilet environment.
Project started: February 2012
Students involved: Geoff Hill
AMS Sustainability funding: $1950