Occurrence and survival of pathogens at different sludge depths in unlined pit latrines in Kampala slums
Loading...
Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Water Sa
Abstract
Occurrence and survival of pathogens in faecal sludge was investigated in unlined pit latrines at varying depths in peri-urban
areas of Kampala city, Uganda. A total of 55 unlined pit latrines, 7 private and 8 rental unlined pit latrines were sampled in the
first and second phases (representing the rainy season) and 40 pits in the third phase (representing dry season), and analysed for
indicator organisms and pathogens from 4 pit latrine sludge layers, at depths of 0, 0.5, 1.0 and 1.5 m, following APHA standard
methods. Physico-chemical parameters of the faecal sludge were also measured. Three sampling phases were undertaken to
determine the effect of seasonal variation. Results indicate that the mean temperature and pH were 25.4 ± 1.14°C and 8.0 ± 1.5,
respectively; and moisture content increased with pit sludge depth, except between Depths 3 and 4. Average moisture content
was 86.3 ± 3%. The measured parameters varied significantly (P > 0.05) between seasons. The mean reduction in total coliforms,
thermo-tolerant coliforms, E. coli, and faecal enterococci with sludge depth was significant at all depths (P < 0.05), but the least
significant difference was not significant at depth levels of 1.0 m and 1.5 m. Salmonella was only detected at the top layer of faecal
sludge in 60% of Phase 2 samples and in only 20% of the samples in Phase 3. About 200–4 100 eggs/g of strongyles were found in
98% of the samples and 100–1 600 eggs/g of ascarids in 55% of the samples. Temperature, pH and moisture content did not show
a significant correlation with observed reductions of indicators and pathogens. With extrapolation of the generated regression
models, a pit of 8 m can be recommended for reduction of bacteria. It is recommended that protective field gear be used during
pit emptying and that faecal sludge treatment should be done to reduce pathogens before disposal into the environment.
Description
Keywords
Pathogens, Indicator organisms, Faecal sludge, Unlined pit latrine, Water contamination
Citation
Nabateesa, S., Zziwa, A., Kabenge, I., Kambugu, R., Wanyama, J., & Komakech, A. J. (2017). Occurrence and survival of pathogens at different sludge depths in unlined pit latrines in Kampala slums. Water Sa, 43(4), 638-645. http://dx.doi.org/10.4314/wsa.v43i4.11