Agricultural Potential of Biosolids Generated from Dewatering of Faecal Sludge on Unplanted Filter Beds.

Abstract

The study was conducted to determine the agricultural potential of biosolids produced from the dewatering of faecal sludge on drying beds in Ghana. It was conducted using bench scale filter beds at KNUST in Kumasi, Ghana. Different filter media were used to dewater FS while different loading rates of FS were dewatered on selected filter medium. Different percentages of sawdust mixed with FS were also dewatered and biolsolids produced were dried and analysed for nutrients and heavy metals. The results showed that the average percentage carbon in all the biosolid ranged between 27 and 42.7%, nitrogen was 1.82 – 3.54% and carbon – nitrogen ratio ranged between 8.7 - 23.9%. The level of phosphorus and potassium ranged between 1.73 – 3.69%and 0.81- 3.78% respectively. The average concentration of heavy metals analysed in the dried biosolids were very low where the range of Cu was 0.081- 0.157mg/kg, Fe 1.530- 4.562mg/kg, Pb 0.009- 0.032mg/kg. Cd, Mn, and Zn showed ranges of 0.036 – 0.092, 0.076-0.652 and 0.026-0254 mg/kg respectively.

Key words: Biosolid, dewatering, faecal sludge, heavy metals, nutrients.