Model-based energy and uncertainty analysis of membrane bioreactor to treat PVC production site wastewater

Abstract

A pilot-scale membrane bioreactor (MBR) was developed to treat poly vinyl chloride (PVC) production site wastewater. Meanwhile, a simulation model based on activated sludge model No.1 (ASM1) was developed and calibrated for the MBR to evaluate performance in terms of effluent quality, energy consumption, and operation strategy reliability. Furthermore, a modified aeration model was proposed taking into consideration the effect of mixed liquor suspended solids (MLSS) on oxygen transfer. The results showed that the calibrated ASM1 was able to simulate NO3-N satisfactorily and simulate NH4-N and MLSS in the aerobic tank reasonably in both steady and dynamic states; the pilot-scale MBR consumed 0.73kWhm3 permeate production. After the calibration and validation of the MBR process model, a scenario analysis (SCA) was conducted to analyze the effect of sludge retention time (SRT), recirculation ratio (R), and dissolved oxygen (DO) on aeration energy demand and effluent quality. Moreover, Latin Hypercube Sampling (LHS) was performed to study the uncertainty of model parameters to judge the reliability of the operation strategy to meet certain criteria. It was evident that the current operation strategy was able to reach the target with an effluent NH4-N concentration lower than 2mgL−1 for about 97% chance.