Determination of biokinetic coefficients for an adsorption/bio-oxidation process on municipal wastewater in pilot-scale

Aims: The present study was carried out to determine biokinetic coefficients of a pilot-scale adsorption-bio-oxidation process. Materials and Methods: The pilot plant was simulated North wastewater treatment plant, Isfahan, Iran. The pilot plant was operated 135 days under different mixed liquor suspended solids (MLSS) concentrations in aeration tank. In each phase, MLSS value was kept constant to reach a steady state condition. B-stage has a higher hydraulic retention time and SRT than A-stage. Also, in order to determine influence of biokinetic parameters on the effluent substrate concentration, a sensitivity analysis was performed. Results: The coefficients Y, K d , K S , and μmax of A-stage were 1.34 mg VSS/mg sCOD, 0.17 d-1 , 8.61 mg/L, and 2.78 d-1 , respectively. Also, Y, K d , K S , and μmax of B-stage were 0.74 mg VSS/mg sCOD, 0.12 d-1 , 3.34 mg/L, and 71.94 d-1 , respectively. Sensitivity analysis showed that in the A-stage, all coefficients are directly proportional to the effluent sCOD concentration. In the B-stage, K d and K S are directly proportional, but μmax was inversely proportional to the effluent sCOD concentration. Conclusions: All coefficients were in the range of activated sludge coefficients that are mentioned in the literature, except μmax and K S of B-stage. However, K S value of B-stage was close to the desired range. Sensitivity analysis showed that μmax and K S have the most influence on effluent substrate concentration (sCOD).