Production and Characterization of Faecal Sludge based Biochar.

Abstract

Faecal sludge is a raw or partially digested slurry that results from the collection, storage or treatment of combination of excreta and blackwater, with or without greywater. The disposal of this material is already causing environmental problems in communities where it is poorly disposed. In Lubigi treatment plant, about 5000m3/day is received and only 3000m3/day of this is treated and the remaining is still untreated. Due to the boost of the improved technology of treating faecal in this country, this faecal sludge provides a great opportunity as a slow pyrolysis feedstock. This research therefore focuses on the production of faecal sludge-based biochar through slow pyrolysis. The objectives of this study are to characterize faecal sludge as a feedstock of slow pyrolysis using Thermogravimetric analysis (TGA), and to produce and characterize biochar derived from the pyrolysis process. Faecal sludge samples were obtained from the Lubigi treatment plant. The initial characterization of faecal sludge revealed high ash content and low volatile matter, rendering it unsuitable for efficient pyrolysis. To address these limitations and enhance the quality of the resulting biochar, faecal sludge was mixed with saw dust, rice husks, and bagasse. Three replicates with saw dust, rice husks, and bagasse and faecal sludge alone under equal proportions were prepared and pyrolyzed under similar conditions. The results of this study showed that biochar from the mixtures of faecal sludge with the organic materials had improved properties compared to biochar from faecal sludge alone and this was shown by the tables of results and graphs plotted. Therefore, it can be concluded that faecal sludge alone produces biochar with poor properties, hence co-pyrolysis with organic materials leads to a significant increase in the biochar properties.