Biological pretreatment of poultry processing wastewater

A biological pretreatment plant for poultry processing wastewater was designed, using an aerated equalization tank followed by two high-rate moving bed biofilm reactors (MBBRs) in series. No solids separation and sludge handling was installed. The solids from the pretreatment plant were discharged to the municipal sewer together with the pretreated wastewater. The pretreatment plant performed well, even at organic loads significantly higher than the design values. With a specific biofilm surface area of 250 m 2 /m 3 and a total volumetric organic load of 30–45 kg COD/m 3 × d on MBBR1, the removal of filtered COD was as high as 80% over MBBR1 and 90–95% over MBBR1 plus MBBR2.