BioLitter Toilet as a valorisation and management strategy for human excreta: Practices, challenges and opportunities

Abstract

Human excreta, i.e. faeces and urine, can both be a resource and a health hazard. Thus, a treatment to ensure health protection can combine with the objective of resource recovery. This statement respects the Ecological Sanitation principle, i.e. sustainable sanitation approach closing the loop between sanitation and agriculture. In BioLitter Toilets, excreta are mixed with carbon-rich substrate, then composted to be recycled. Composting is a well known process widely used to recycle organic matter. However, its seems that composting has not been studied yet for human faeces and urine regarding low-tech household-scale systems in Belgium. The first objective of this work is thus the identification of management practices regarding BLTs operators using the snowball sampling method. The second objective consists of characterization of raw feedstocks and composts of different ages and inputs to collect quantitative data and discuss them regarding (a) the practices and process, (b) the agronomic value, (c) the potential health hazards. These results highlighted a broad range of management practices regarding dry toilets, with or without resource recovery, treatment, and thermophilic composting as a treatment. While technical aspects concerning the process and the logistics are theoretically easier to spot and solve, social reluctance and inconsistent practices are the main barrier to the development of this sanitation technique. Furthermore, quantitative characterisation suggest that thermophilic stage was not reached in several of the sampled composts, which impacts its sanitation potential. This result is confirmed by Enterococci values. Neither Salmonella nor Listeria monocytogenes pathogenic load were found in any sample. Management practices suggested include temperature monitoring and associated turnings and co-composting to increase volumes and potentially heat insulation and thermophilic conditions. Moreover, risk management strategies are considered to dismiss health hazard. An overview of the current state of the management practices in Belgium is finally proposed using the SWOT approach.