Performance Studies on Biological Treatment of Slaughterhouse Wastewater Using Mixed Culture in Sequencing Batch Reactor

The slaughterhouse and meat processing units generate large volumes of wastewater containing high organic and nitrogenous substances (COD, NH4+-N), which require considerable degree of treatment before discharge to the water body. In this regard, selecting an effective treatment system is important. Amongst various biological treatment systems sequencing batch reactor (SBR) is comparatively noble bioreactor system for treating waste containing carbon and nitrogen simultaneously. The performance of a 20 L sequencing batch reactor (SBR) treating wastewater discharged from a local small-scale slaughterhouse was examined in the laboratory at ambient temperature. The reactor was operated under three different variations of aerobic-anoxic sequence, viz. 4 + 4, 5 + 3 and 3 + 5 hours of total react period with influent soluble COD (SCOD) and ammonia nitrogen level 1000 +/- 50 mg/L & 90 +/- 10 mg/L and 2000 +/- 50 mg/L & 180 +/- 10 mg/L, respectively. It has been observed that 80 to 96% of SCOD removal would be possible at the end of eight hours of overall reaction period, irrespective of the length of the aerobic react period. In case of 4+4 aerobic-anoxic operating cycle, reasonable degree of nitrification 89.48% and 81.58% corresponding to initial NH4+-N value of 87.52 mg/L and 185.24 mg/L respectively, along with 94.07% and 90.23% of organic carbon removal corresponding to initial SCOD value of 1015.24 mg/L and 2028.55 mg/L respectively, have been achieved after eight hours of react period for treatment of slaughterhouse wastewater in SBR.