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

ABSTRACT

A 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 (k_d), and half-velocity constant (K_s) were also determined to improve the design and operation of package effluent treatment plants comprising SBR units. The specific denitrification rate (q_DN) 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, k_d and K_s 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.

KEYWORDS:

• abattoir wastewater
• biokinetic coefficients
• denitrification
• nitrification
• organic carbon oxidation
• sequencing batch reactor