Application of Process Intensification in the Treatment of Pit Latrine Sludge from Informal Settlements in Blantyre City, Malawi

Khumbo Kalulu, Bernard Thole, Theresa Mkandawire and Grant Kululanga
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Khumbo Kalulu: Department of Environmental Health, University of Malawi, Faculty of Applied Sciences, P/Bag 303, Chichiri, Blantyre 3, 312225, Malawi
Bernard Thole: Department of Physics and Biochemical Sciences, University of Malawi, Faculty of Applied Sciences, P/Bag 303, Chichiri, Blantyre 3, 312225, Malawi
Theresa Mkandawire: Department of Civil Engineering, University of Malawi, Faculty of Engineering, P/Bag 303, Chichiri, Blantyre 3, 312225, Malawi
Grant Kululanga: Department of Civil Engineering, University of Malawi, Faculty of Engineering, P/Bag 303, Chichiri, Blantyre 3, 312225, Malawi

IJERPH, 2020, vol. 17, issue 9, 1-14

Abstract: Many developing countries lack the infrastructure needed for the treatment of fecal sludge. One limitation in implementing available treatment options is the limited availability of land in the urban areas of these countries. This paper investigated the application of process intensification as a way of reducing the land area required to dewater and sanitize pit latrine sludge from informal settlements in Blantyre City, Malawi. The intensification of the sludge treatment process was achieved by enhancing dewatering through the application of additives and by combining the dewatering and sanitization stages. Nine combinations of sludge, lime and rice husk dosages, in addition to a control, were simultaneously loaded on unplanted drying bed units to dewater for 29 days. The study found a significant reduction of 21% to 73% in the land area required to dewater and sanitize pit latrine sludge. From the study, process intensification was shown to have the potential to significantly reduce the land area required to dewater and sanitize pit latrine sludge from informal settlements in Malawi cities. This makes it an option that can be implemented close to informal settlements, despite land limitation in these areas.

Keywords: dewatering and sanitization; unplanted drying bed; sludge dewatering cycle time; sludge solids loading rate; sustainable sanitation (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2020
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