Kinetic Modeling for Simultaneous Organic Carbon Oxidation, Nitrification, and Denitrification of Abattoir Wastewater in Sequencing Batch Reactor

Abstract

ABSTRACTA laboratory-scale study was conducted in a 20.0-L sequencing batch reactor (SBR) to explore the feasibility of simultaneous removal of organic carbon and nitrogen from abattoir wastewater. The reactor was operated under three different combinations of aerobic-anoxic sequence, viz., (4+4), (5+3), and (5+4) h of total react period, with influent soluble chemical oxygen demand (SCOD) and ammonia nitrogen (NH4+-N) level of 2200 ± 50 and 125 ± 5 mg L−1, respectively. In (5+4) h cycle, a maximum 90.27% of ammonia reduction corresponding to initial NH4+-N value of 122.25 mg L−1 and 91.36% of organic carbon removal corresponding to initial SCOD value of 2215.25 mg L−1 have been achieved, respectively. The biokinetic parameters such as yield coefficient (Y), endogenous decay constant (kd), and half-velocity constant (Ks) were also determined to improve the design and operation of package effluent treatment plants comprising SBR units. The specific denitrification rate (qDN) during anoxic condition was estimated as 6.135 mg N/g mixed liquor volatile suspended solid (MLVSS)·h on 4-h average contact period. The value of Y, kd and Ks for carbon oxidation and nitrification were found to be in the range of 0.6225–0.6952 mg VSS/mg SCOD, 0.0481–0.0588 day−1, and 306.56–320.51 mg L−1, and 0.2461–0.2541 mg VSS/mg NH4+-N, 0.0324–0.0565 day−1, and 38.28–50.08 mg L−1, respectively, for different combinations of react periods.