Biological treatment of dairy plant wastewater1

Abstract

Abstract The influent and effluent wastewaters of a Sequencing Batch Reactor (SBR) wastewater treatment system used by a dairy processing plant were evaluated over a two‐month period. Pollution parameters measured were biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total solids (TS), and pH. Viable biomass of the samples was determined by adenosine triphosphate (ATP), measured in Relative Light Units (RLU) and heterotrophic plate count (HPC). The following average overall reduction of pollution parameters was achieved by the SBR system: BOD, 97%; COD, 93%; TSS, 97%; and TS, 76%. Biochemical oxygen demand was highly correlated with COD, TS, TSS, HPC, and ATP in the effluent. A significant correlation was also observed between ATP and HPC. The pH of the influent and effluent ranged from 7 to 8. The average daily effluent flow rate of the waste disposal system was approximately 94,625 liters with an average BOD of 8mg/l, COD of 72mg/l, TSS of 15mg/l, TS of 728mg/l and pH of 7.62. With the efficient reduction of BOD, COD, TS, and TSS, the SBR system was effectively used for the primary and secondary treatment of wastewater.