Anaerobic treatment of leachate from faecal sludge drying beds

Thumbnail Image
Journal Title
Journal ISSN
Volume Title
Physicochemical and microbiological analyses were carried out on the leachate from faecal sludge drying beds of a Pilot Co-composting Plant at Buobai in Kumasi from February 8 to July 15, 2002 in order to ascertain the quality of the leachate and propose a management system for it. For a dewatering cycle, the first day, last day and the composite leachate samples were analysed. The average quality parameters obtained for the leachate were 305 mg/l SS, 3,052 mg/l COD, 881 mg/l BJD, 415 mg/I NH3-N, 265 mg/l P04-P and 1.12 x 106 per l00ml Faecal coliforms. These values when compared with the EPA recommended discharge guidelines show that the leachate is poor in quality and thus requires treatment prior to reuse or discharge into the environment. In investigating the treatment of the leachate, it was subjected to a laboratory scale anaerobic treatment. Two categories of leachate samples were investigated; samples seeded with anaerobic sludge and samples without seeding. The maximum percentage removals for the unseeded leachate after 6 days of treatment were 70% 52.4%, 57.7%, 28.1 and 29.4% for SS, COD, BOD, PO4-P and Faecal coiiform respectively. For the seeded leachate, the removals were 72.7%, 56.1%, 57.9%, 19.1% and 28.2% respectively for SS, COD, BOD, PO4-P and Faecal coliform. The values for the seeded leachate were not significantly different from those for the unseeded leachate. Thus, for anaerobic treatment of the leachate no seeding is required. The anaerobic treatment could not produce the desired quality for reuse or discharge into water bodies. It is therefore recommended that additional treatment is necessary to further lower the pollution load of anaerobic treated leachate effluents and to reduce public health risks.
A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements for the award of Master of Science in Water Supply and Environmental Sanitation, 2001