The model developed by Sanergy in Kenya addresses various barriers that can prevent people from accessing safe sanitation. Easy-to-install, flush-free, urine-separating toilets are operated by franchisees, who charge a small fee for each use; water and soap are also provided.
The principle of container-based sanitation is demonstrated clearly with this image of a deconstructed Fresh Life Toilet. The plastic top plate diverts urine and faeces into separate containers, holding 25-30 litres and 40–50kg of waste, respectively. These are collected frequently, often daily, depending on level of use.
Solid waste is taken to treatment sites where it is upcycled into useful products. Colonies of black soldier flies are reared on a medium including solid waste from the toilets; protein is then harvested from the flies’ larvae (pictured below), pasteurised and packaged as a high-protein ingredient of animal feed.
Residue generated by the flies is composted to produce an organic fertiliser, which is sold to farmers to improve their yields. Remaining residue is compressed at high temperature and pressure to manufacture biomass briquettes for industrial use.
The Sanergy franchise model also encourages local enterprise and provides an economically sustainable model for low-income communities.
Container-based sanitation can be a good solution for places where access to water or sewer systems is limited, particularly rapidly growing urban areas in developing countries. Typically, usage costs are low, so such solutions are more accessible by households, schools and communities in developing countries. But it’s also an option for other situations where similar challenges are faced, such as festivals, or for reducing water use and waste.