Hydrothermal treatment of human biowastes as an alternative sanitation strategy

One of the evolving approaches to mitigating the challenges of poor sanitation involves the exploration of new, sustainable and affordable solutions. These need to be capable of effectively treating faecal and other related wastes without any health, or environmental damage and competitive with existing strategies. This paper presents results from hydrothermal carbonization (HTC) of human biowastes; treated at >130°C under pressure. Analysis shows the process is autothermic and could generate valuable end-products. These were a carbonaceous solid material i.e. char with a high calorific value which can be used as a fuel or soil conditioner, and liquid ammonia concentrate for fertilizer. The results of this study provide useful information essential for the design and operation of a HTC system (for faecal sludge treatment) which will be integrated into a self-sustainable sanitation facility planned for protoype development.