Research On The Method Of Differential Removal Of Pollutants In Polymer-containing Waste Water Based On Bio-augmentation

The main oil fields in China had entered the late stage of high water cut development.Therefore,polymer flooding technology was widely used in oil fields to ensure the output and efficiency of oil exploitation.A large amount of produced water containing polyacrylamide（PAM）was discharged into the environment after treatment.The existing biochemical treatment process had obvious effect on the degradation of the side chain amide group of PAM,while the total organic carbon（TOC）removal rate was only 30%-40%.The effluent contained a large amount of long-carbon chain polyacrylic acid,oligomeric PAM fragments,polyacrylate and other residual substances.Residual PAM would decompose in the natural environment to produce neurotoxin—acrylamide monomer,which was easy to accumulate,migrate,and difficult to transform in the environment.Existing biological treatments could not further mineralize these residual macromolecules.Therefore,it was urgent to explore a bioaugmentation mode that simultaneously removes and synergistically mineralizes the above-mentioned residuals to achieve the purpose of deep mineralization of PAM and its degradation products.Based on the simulated biological treatment system,this research screened specific degrading bacteria for different degradation products of polyacrylamide and selected the optimal combination through compounding.Finally,the simulated biological treatment system was strengthened with an exogenous compound bacterial agent,the following conclusions are drawn:1.The information of the indigenous microbial community structure in the research system was simulated through the biological processing system.Design experiments by adjusting the types and concentrations of co-metabolites in the system.The glucose concentration was 100 mg/L,200 mg/L,300 mg/L,the liquid paraffin concentration was 0.1m L/L,0.2 m L/L,0.3 m L/L,and the NH₄Cl concentration was 100 mg/L,200 mg/L,300mg/L,concentration gradient experiment of yeast extract powder concentration of 100 mg/L,200 mg/L,300 mg/L,to explore the optimal biological system degradation conditions.Finally,it was found that the optimal co-metabolic carbon source for the simulated biological treatment system under non-bioaugmentation conditions was liquid paraffin with a concentration of 0.2 m L/L,and the optimal co-metabolic nitrogen source was yeast extract powder with a concentration of 100 mg/L;2.Use polyacrylamide and sodium polyacrylate as substrates to screen high-efficiency degrading bacteria for different components in poly-containing wastewater,study their growth state in poly-containing wastewater and the removal effect of polyacrylamide and TOC,and prepare into a compound bacterial agent.The four PAM-degrading bacteria S-1,S-2,G-1,and G-2 were screened and belonged to Ochrobactrum anthropi,Acinetobacter venetianus,Pseudochrobatrum sp.and Bacillus cereus.The S-2 and G-2 combination of compound bacterial agents was the optimal combination,and the degradation effect of the simulated polymer-containing wastewater was more significant;3.Exogenous bacterial agents strengthened the biological treatment system.The prepared compound inoculum was added as an exogenous intensified inoculant to the original treatment system,and the influence of the bio-enhancement of the compound inoculant on the"indigenous bacteria"was explored by adjusting the process conditions and operating parameters.By observing the community succession of indigenous flora and exogenous flora in the system,the content of various indicators of simulated polymer-containing wastewater was detected to provide theoretical support for the biological synergistic deep mineralization of polymer-containing wastewater.Studies had found that the exogenous compound microbial agents had a good synergistic effect with the indigenous flora in the system.The addition of exogenous bacterial agents enhanced the system’s ability to treat simulated polymer-containing wastewater.