A/O-MBR process debugging for enhancing denitrification and decarbonization of refining wastewater and simulation research

Abstract

In this paper, the sewage treatment plant of a petrochemical company in Shaanxi Province was used as the research object to optimize the effect of nitrogen and carbon removal by adjusting the operating parameters of A/O-MBR pilot system, and the mathematical model of sewage biological treatment system based on the activated sludge models(ASMs) was established to simulate the sewage treatment process. The results of operation and debugging showed that the AO5 process still could not ensure the effluent meet the standard after optimizing the operation parameters. Then the residence time of the anoxic zone was extended from 4 h to 8 h by changing the original AO5 process to A2O4 process. Under the conditions of 20% filling ratio in the aerobic tank, 100% sludge reflux in the anoxic tank, and 200% nitrate liquid reflux, effluent COD, NH4+-N, and TN were 28.53 mg/L, 0.24 mg/L, and 12.22 mg/L, respectively, which met the concentration limit standards for other units of water pollutants in Table 2 of the Integrated Wastewater Discharge Standard of Yellow River Basin in Shaanxi Province(DB 61/224-2018). In addition, the Ind. ASM-Petrochem model based on the ASMs model could simulate the removal of COD and NH4+-N accurately, while further improvement was needed for the simulation of TN.

Keywords

• a/o-mbr
• nitrogen and carbon removal
• retention time
• filler
• ind. asm-petrochem model