Document Type : Original Article

Authors

• Mostafa Hadei ¹
• Mohammadreza Aalipour ¹
• Ali Fatehizadeh ¹
• Hamid Reza Safavi ²
• Mohammad Ghasemian ³
• Ahmad Reza Sahbaei ³
• Seyyed Mohammad Mousavi ³
• Mohsen Ashjaa Zadeh ³
• Mohammad Mehdi Amin ⁴

¹ Department of Environmental Health Engineering, Student Research Center, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran

² Department of Civil Engineering, Research Institute for Water and Wastewater, Isfahan University of Technology, Isfahan, Iran

³ Environmental Research Center, Research Institute for Primordial Prevention of Noncommunicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran

⁴ Environmental Research Center, Research Institute for Primordial Prevention of Noncommunicable Disease, Isfahan University of Medical Sciences, Isfahan; Isfahan Water and Wastewater Company, Isfahan, Iran

Abstract

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 μ_max 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 μ_max 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 μ_max 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 μ_max and K _S of B-stage. However, K _S value of B-stage was close to the desired range. Sensitivity analysis showed that μ_max and K _S have the most influence on effluent substrate concentration (sCOD).

Keywords

• A-B process
• adsorption-bio-oxidation process
• biokinetic coefficients
• two-stage activated sludge