Effect of Thermal Treatment on Microbial load of Faecal Sludge From Some Faecal Sludge Collection Sites in Oyo State, South Western, Nigeria

Faecal sludge which is usually highly laden with pathogenic microorganisms serves as a route of disease transmission especially when used as organic amendment or when it contaminates water sources. Therefore, the present study investigates the effect of thermal treatment on the microbial load of faecal sludge. Faecal sludge samples were collected from two major faecal collection points in Ibadan metropolis, the samples were subjected to chemical (proximate minerals and heavy metals) and microbiological (bacteriological, mycological and parasitological) analysis before and after thermal treatment. The chemical analysis of the faecal sludge samples before and after treatment revealed the presence of heavy metals such as lead, chromium and zinc among others; proximate matter, such as protein, fat and fibre, and minerals contents such as sodium and potassium. Microbiological examination before treatment revealed that the faecal sludge samples had a high microbial load of species such as Bacillus, Salmonella, Aspergillus among others and ova of Ascaris. However, after the thermal treatment of the faecal sludge samples, it was observed that the microbial load was reduced as only spore forming organisms such as Bacillus and Aspergillus could be observed. It was observed that most organisms present in faecal sludge were removed as a result of thermal treatment; this implies that faecal sludge can be made safe for use in agricultural practices by application of thermal treatment. The present study shows the efficacy of thermal treatment in reducing the microbial load of faecal sludge, thereby increasing its chances of been used as organic amendment in agricultural practices.