Design and construction of a portable unplanted drying bed for faecal sludge treatment.

Abstract

The most common on-site sanitation systems (OSS) used in Kyaka II refugee settlement are pit latrines including individual and public ones. Currently, there is no disposal facility for treating emptied faecal sludge (FS) from the OSS which poses severe risks to both human health and environment at large. This research therefore, aimed at designing and constructing an experimental physical model for testing the performance of unplanted drying beds system for treating FS from OSS by characterizing it in order to know its physio-chemical properties and quantifying the FS purposely to know the quantities to be treated overtime for the ultimate design year of 2046. The results from the laboratory analysis of the sludge indicated that the high strength nature of the FS with an average Total Solids concentration of 33.44g/l. This and other field data obtained during the research were used to come up with the design of the beds for treating the settlement’s FS in order to reduce its level pollutant concentration before discharge into environment and/or disposal or re-use of the by-product. The physical experimental model was set up in the field to test the performance of the system upon treatment of the FS generated within the settlement. The environmental impact Analysis (EIA) upon discharge of the leachate was also carried out. In the physical model, the FS was screened with a bar screen structure and allowed sludge to be loaded in batches and the structure monitored for 19 days to collect the leachate for analysis and from the EIA basing on percentage removals, the structure was recommended for the treatment of sludge from the settlement.