Sequencing batch reactors for the treatment of egg processing wastewater

Due to plant expansion, a British Columbia egg processor was looking for a means of increasing the capacity of an aerated lagoon system for treating egg processing wastewater. To avoid a major capital investment, upgrading to a sequencing batch reactor (SBR) appeared to be an attractive option. For this reason, two parallel lab-scale SBR systems were operated over an eight month period for the treatment of egg processing wastewater. The results showed very good removal rates of 99% for BOD, 88% for COD, and 65% for TSS. Aeration requirements were found to be 1.5 L/min and 0.5 L/min for two 4 litre reactors in series. The coefficients a and b, for the detennination of ox?,gen requirements, were established at 0.68 g 02lg BOD and 0.32 d- , respectively. Dissolved oxygen levels between I and 3 mg/L were maintained at a design mean cell residence time of 20 days. Colifonns were reduced from 3500 MPNII 00 mL in the influent to 80 MPN/l 00 mL in the effluent. Confinned coliforms were identified as Bacillus sp. and Micrococcus sp. Salmonella and fecal coliforms were not detected in either the influent or effluent wastewater.