Abattoir effluent treatment and protein production

A modified SBR process was evaluated for biological pretreatment of abattoir effluent. One of the main objectives was to produce a biomass with low SVI that can be used as a protein feed addition for animals. A pilot plant was used with reactor working volume of 60 kl. The process was easy to operate and adapted readily to changes in raw effluent generation. COD removal was in excess of 85%. A biomass was produced with SVI lower than 80 ml/g that included aerobic granular sludge. Filamentous organism growth could be limited by controlling the dissolved oxygen concentration in the reactor. Crude protein values of 27 to 37% were obtained. The optimum cell residence time to maximise protein production was between 4 and 5 days. The process can be described as a protein recovery and production process.