Abattoir effluent treatment and protein production: Full-scale application

Abstract

A modified sequencing batch reactor (SRB) process was evaluated at full scale for the pretreatment of abattoir effluent and for the production of protein that can be used as an animal feed supplement. Successful pretreatment was achieved with unfiltered COD removal in excess of 90% and filtered COD of less than 200 mg/l. The process adapted readily to variation in effluent volume, flow rate and duration, and was self-regulating. The peak oxygen supply, and therefore power requirements, was reduced by incorporating an anoxic phase during the Fill period. The biomass produced had a crude protein value of c. 40% and was successfully used as a supplement to carcass meal for animal feed. An economic feasibility study showed a net income from protein sales compared to running expenses and a major saving on effluent tariffs, recovering all expenses within the first year of operation . Comparison of the results with those of a previously completed pilot-plant study, showed differences, emphasising the importance and risk involved in scale-up.

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