Evaluation of the Effect of Adding Rock Phosphate to Anaerobic Digestion of Waste Chicken Feathers for Biogas Production

The effect of adding different concentrations of Rock Phosphate (RP) to the anaerobic digestion of Chicken Feather (CF) on yield kinetics and biogas production was investigated in the present research work. Nine identical batch digesters (Labeled A–I) were employed in the present experimental investigation. Digester A contained only CF (20 g) and remaining each digester contained 20 g of CF and varying RP concentration from 2.5 to 20% based on the total weight of CF. The cumulative biogas generation from digesters having the combinations CF:0% RP, CF:2.5% RP, CF:5% RP, CF:7.5% RP, CF:10% RP, CF:12.5% RP, CF:15% RP, CF:17.5% RP, and CF:20% RP are 268, 952, 1098, 968, 970, 882, 875, 832, 838 ml/20 g CF respectively. It was found from the Modified Gompertz Model that the addition of RP to anaerobic digestion of waste CF had a positive effect of 252.71%, 232.35%, and 1.68% on the total amount of biogas generated (A), optimum specific biogas generation (μ_m) and latency (λ) respectively over untreated CF. The addition of RP to the anaerobic digestion of leftover CF is a very simple, practical, and efficient process that produced biogas in a beneficial way.