Table of Contents
Journal of Waste Management
Volume 2016, Article ID 2717304, 8 pages
Research Article

Off-Site Lime Stabilisation as an Option to Treat Pit Latrine Faecal Sludge for Emergency and Existing On-Site Sanitation Systems

1The Polytechnic, The University of Malawi, Private Bag 303, Blantyre, Malawi
2WASTE Advisers on Urban Environment and Development, Lange Houtstraat 26, 2511 CW The Hague, Netherlands

Received 9 December 2015; Accepted 17 April 2016

Academic Editor: Alfieri Pollice

Copyright © 2016 Wilson Greya et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Off-site lime stabilisation for treating faecal sludge was assessed by undertaking small-scale (35 L) and large-scale (600 L) field trials in Blantyre, Malawi. Hydrated lime was dosed to maintain pH 10, pH 10.5, pH 11, pH 11.5, and pH 12 depending on the buffer capacity of the faecal sludge in the four replica small-scale field trials. Significant reduction of E. coli to below the detection limit of 104 CFU/100 mL within 1 hour of treatment was reported for pH > 11. Based on the small-scale findings, large-scale field trials were conducted and greater than removal of E. coli was observed under pH 12 conditions. Therefore, based on the study, off-site lime stabilisation by dosing lime in the range of 10–35% w/w (dry solid basis), depending on the buffer capacity and solids content of the sludge to maintain pH > 11, can be used to sanitise faecal sludge during emergencies, as well as for existing on-site sanitation systems.