Experimental Study On Functional Flora And Impact Resistance Of CAST Reactor For Heavy Oil Processing Wastewater

Due to the fluctuation of water quality of refinery wastewater and partial leakage of upstream equipment,the activated sludge of Liaohe Petrochemical Wastewater Treatment Plant is often affected by toxic and harmful wastewater.So the stable and efficient operation of cyctic activated sludge reactors in heavy oil refinery has become an urgent necessity in wastewater bio-treatment.Here,we investigated nutrient concentrations,ratios and additions of composite bacteria,and agent dosages to formulate and optimize microbial agents.Then,cyctic activated sludge reactor performance was assessed by agent addition under three simulated shock conditions.High-throughput sequencing technology was used for the characterization of the microbial community structures in the reactors.Results showed that(1)The addition of 0.1%(Kg solid microbial agent/m3 wastewater)optimal microbial agents(the ratio and addition of composite bacteria were 3:1 and 3.0%,respectively,and the Nutrients concentration was 5.0 mg/L)effectively resisted different organic shock loadings within 15 days.This provides sufficient time for enterprises to investigate the sources of problems.(2)The effluent CODcr of the reactor with solid microbial agents and nutrients is about 45mg/L,which meets the local sewage discharge standard of Liaoning Province.The average removal efficiency of chemical oxygen demand and total nitrogen reached 86% and 55%,respectively.(3)Burkholderiaceae and Ruminococcaceae were the dominant bacterial families in wastewater and activated sludge,respectively.The results show that the living environment of microorganisms is the main reason for the changes in the structure of the flora.In this study,the microbial method was used to solve the problem that the activated sludge was vulnerable to impact,which provided a valuable reference for the upgrading of the heavy oil processing wastewater treatment process.