This study aimed at estimating the sanitizing effectiveness of urea treatment by studying the inactivation kinetics of selected indicator microorganisms. Finished composts from a composting toilet were inoculated with indicator microorganisms and subjected to different urea concentrations (0.5–2% w/w) and temperatures (22, 32 and 42°C). The inactivation kinetics parameters were determined in relation to pH, ammonia content and temperature during treatment time. The results show that urea addition to compost enhanced inactivation of microorganisms. The decline in number of E. coli and Enterococus followed a linear reduction, while that of Ascaris lumbricoides eggs followed a linear reduction plus shoulder. The inactivation rate constants of all microorganisms tested were positively correlated to the increase of NH3(aq) concentration and temperature. The relationship between the inactivation rate of microorganisms, ammonia through urea concentration and temperature were established. Therefore, the best decimal decay of E. coli, Enterococus and A. lumbricoides eggs occurred with 2% w/w urea concentration at 42°C within 0.9, 1.1 and 1.4 days, respectively. E. coli was the most sensitive microorganism to urea treatment, while Enterococcus and A. lumbricoides eggs showed resistance, especially at lower temperatures. Urea treatment has proved to be an efficient option for safe reuse of compost from composting toilets.
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Research Article|
May 31 2016
Inactivation kinetics of indicator microorganisms during urea treatment for sanitizing finished compost from composting toilet Available to Purchase
Seyram K. Sossou;
1International Institute for Water and Environmental Engineering (2iE), P.O. Box 594, 01 Rue de la science, Ouagadougou, Burkina Faso
E-mail: [email protected]
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Mariam Sou/Dakoure;
Mariam Sou/Dakoure
1International Institute for Water and Environmental Engineering (2iE), P.O. Box 594, 01 Rue de la science, Ouagadougou, Burkina Faso
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Yacouba Konate;
Yacouba Konate
1International Institute for Water and Environmental Engineering (2iE), P.O. Box 594, 01 Rue de la science, Ouagadougou, Burkina Faso
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Amadou H. Maiga;
Amadou H. Maiga
1International Institute for Water and Environmental Engineering (2iE), P.O. Box 594, 01 Rue de la science, Ouagadougou, Burkina Faso
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Naoyuki Funamizu
Naoyuki Funamizu
2University of Hokkaido, Kita 13-Nishi 8, Kita-ku, Sapporo, Hokkaido 060–8628, Japan
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Journal of Water, Sanitation and Hygiene for Development (2016) 6 (2): 269–275.
Article history
Received:
May 20 2015
Accepted:
May 03 2016
Citation
Seyram K. Sossou, Mariam Sou/Dakoure, Yacouba Konate, Amadou H. Maiga, Naoyuki Funamizu; Inactivation kinetics of indicator microorganisms during urea treatment for sanitizing finished compost from composting toilet. Journal of Water, Sanitation and Hygiene for Development 1 June 2016; 6 (2): 269–275. doi: https://doi.org/10.2166/washdev.2016.090
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