Contextual investigation of factors affecting sludge accumulation rates in lined pit latrines within Kampala slum areas, Uganda
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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Water SA
Abstract
Pit latrines in slums areas of Uganda fill up faster than might be expected from some estimates owing to inappropriate
use and failure to consider critical factors affecting sludge accumulation rates at the planning, design and construction
stages. This study sought to investigate factors affecting filling rates of lined pit latrines in slum areas of Kampala with the
goal of contributing to accurate planning, design, construction, emptying and overall maintenance. Fifty-five pit latrines
were selected from the five divisions of Kampala city using stratified random sampling. Data collected included: number
of users, frequency of emptying, years taken since last emptying, type of non-faecal materials deposited, cross-sectional
dimensions of the pit, rate of sludge degradation and geo-physical factors of pit location. Methods used were: field surveys,
questionnaires and key informant interviews plus on-site depth measurement. Mass loss tests to investigate the rate of sludge
degradation were carried out in the laboratory at moisture content levels similar to those in pit latrines. Sludge accumulation
rates were calculated using volume of sludge in the pit, number of users and time taken since last emptying. Statistical
analyses included correlation and one-way ANOVA. Results revealed that number of users and type of material deposited
in the pit latrines, especially non-faecal matter, had a significant (p < 0.05) effect on sludge accumulation rate. Public pit
latrines with a higher number of users had lower sludge accumulation rates and this was attributed to greater degradation
taking place and greater restriction on entry of non-faecal matter. The rate of sludge degradation was higher at 90–100%
than 80–90% moisture content, due to better degradation conditions. Tighter restrictions on non-faecal material deposition
into pit latrines are recommended to reduce filling rates of pit latrines in slum areas.
Description
Keywords
Sludge accumulation rates, Slum areas, Faecal matter, Degradation, Lined pit latrines
Citation
Zziwa, A., Lugali, Y., Wanyama, J., Banadda, N., Kabenge, I., Kambugu, R., ... & Tumutegyereize, P. (2016). Contextual investigation of factors affecting sludge accumulation rates in lined pit latrines within Kampala slum areas, Uganda. Water SA, 42(3), 490-495. http://dx.doi.org/10.4314/wsa.v42i3.15