Determination of optimal operating factors via modeling for livestock wastewater treatment: Comparison of simulated and experimental data

• Modified four-stage Bardenpho process for livestock wastewater treatment was used.
• Parameters of ASM1 were calibrated to minimize concentration differences.
• Operational optimization via MRSM was performed to meet water quality standards.
• Applicability of modeling method was evaluated via an actual pilot-scale operation.

This study evaluated the optimized operational conditions of a modified four-stage Bardenpho process via modeling for livestock wastewater treatment. The objective is to determine whether the effluent Korean water quality standards can be met using the modified process and ozone/activated carbon reactors. The parameters related to microbial respiration (i.e., YH, YA, μH, bH, and iXB) and effluent concentrations (i.e., fp, ηg, Kh, and ηh) in GPS-X based on ASM1 were calibrated according to the influent characteristics. Consequently, the differences in the COD and TN concentrations of the calibrated and experimental results were 29.58 and 19.15 mg/L, respectively. A modeling method based on multiple RSM was used to determine the optimized operational conditions, resulting in a DO concentration of 6.6 mg/L in each aerobic reactor, an internal recycling rate of 4.9Qin, and a sludge recycling rate of 1.4Qin. Although the COD and TN concentrations during actual operation using the optimized conditions were slightly different than those predicted by GPS-X, the differences were not significant; therefore, the effluent Korean water quality standards were satisfied. With more specific criteria that reduce the differences between the predicted and actual concentrations, the modeling method for operational optimization would be sufficient under any circumstances.