| Petrochemical wastewater is derived from the petroleum products processing field,which served the oil as main raw material.Because of the rich product categories and their own characteristics in petrochemical industry,petrochemical wastewater has the characteristics of variety of diverse,complex composition,high concentration of pollutants,and low biodegradability.Petrochemical industry has a high degree of dependence on water resources,and the petrochemical industry has a large scale in China.Thus,the proper handling of petrochemical wastewater has become an important factor,which could influence the benign development of China's petrochemical industry.Some kind of petrochemical wastewater with salinity and sulfate could inhibit the activity of microorganisms in the biological phase,which poses a challenge to the biodegrada tion of the petrochemical wastewater.The research could provide new process and theoretical basis for the treatment of sulfate petrochemical wastewater,the microbial community data obtained from this research could provide references for the operation of practical process.According to the characteristics of saline,sulfate-petrochemical wastewater,the sulfur metabolism integrated process was used to treat the petrochemical wastewater in the research.The valent change of sulfur was used in the integrated process.In the anaerobic reactor,the Sulfate-Reducing Bacteria(SRB)reduce the sulfate while degrading the organic matter,and the generated sulfide could serve as electron donor for autotrophic denitrification in the anoxic reactor.In the batch experiments,three groups of experiments were designed to analyze the degradation rule of contamination in the integrated process,including the effect of COD/sulfate and salinity on sulfate reduction and COD degradation.In the anaerobic reactor of the integrated process,the sulfate reduction was regulated by the concentrations of sulfate and organic substance.The increase of sulfate/COD ratio didn't affect sulfate reduction and COD degradation at the condition of organic substance limited.In the anoxic reactor of the integrated process,the concentration of sulfide and nitrate should be controlled at suitable ratio to guarantee the maximal denitrification efficiency.The anaerobic reactor could keep high efficiency on sulfate reduction and COD degradation at the 6g/L salinity condition,of which was one of the three set salinity condition.In the research,the sulfur metabolism integrated process was used for the treatment of neutralization tank wastewater,reverse osmosis concentrate,nanofiltration concentrate,and desulfurization wastewater.At the stable operational period of the integrated process,the removal efficiency of COD was 83.60%,and the average concentration of COD,ammonium nitrogen,and total nitrogen in the final effluent were 57.64mg/L,1.65mg/L and 8.72mg/L,respectively for the treatment of neutralization tank.At the stable operational period of the integrated process,the removal efficiencies of COD,ammonium nitrogen,and total nitrogen were 80.79%,79.84%,and 84.57%,respectively for the treatment of reverse osmosis concentrate,the average concentration of COD,ammonium nitrogen,and total nitrogen in the final effluent were 57.41mg/L,2.45mg/L and 14.07mg/L,respectively.The removal efficiencies of COD,ammonium nitrogen,and total nitrogen were 76.16%,83.83%,and 73.06%,respectively in the integrated process for the treatment of nanofiltration concentrate,the average concentration of COD,ammonium nitrogen,and total nitrogen in the final effluent were 106.29mg/L,5.39mg/L and 19.09mg/L,respectively.At the stable operational period of the integrated process,the removal efficiency of COD was 89.05%,and the average concentration of COD in the final effluent was 28.88mg/L for the treatment of desulfurization wastewater.The removal efficiencies of ammonia nitrogen and total nitrogen were 30.77% and 45.17%,and the average concentration of ammonia nitrogen and total nitrogen in the final effluent were 1.98mg/L and 13.91mg/L,respectively.These four petrochemical wastewaters,used in the study,contained many kinds of organic pollution,including long-chain alkane,halo-hydrocarbon and aromatic compound.After the treatment of the process,the molecular weight of the containing organic matter in the final effluent was smaller,and the structure tends to be simple.In the anaerobic reactors for the treatment of reverse osmosis concentrate,nanofiltration concentrate,desulfurization wastewater,SRB played important role on the degradation organic matter.Through high-throughput pyrosequencing,the microbial communities in the process for the treatment of neutralization tank,reverse osmosis concentrate,nanofiltration concentrate,and desulfurization wastewater,were analyzed.I n the anaerobic,anoxic,and aerobic reactors of the process for the treatment of neutralization tank wastewater,the most abundant groups at genus level were Pirellula,Chlorobium,and Hyphomicrobium,respectively.Genus Clostridium belong to class Clostridia,and this class could degrade organic pollutants.Hyphomicrobium is associated with nitrogenous organic's degradation.In the process for the treatment of reverse osmosis concentrate and nanofiltration concentrate,Azoarcus,Paracoccus,and Thauera were detected,which were associated with denitrification.In the anoxic reactor for the treatment of reverse osmosis concentrate,the abundance of Azoarcus could achieve 19.03%.In the process for the treatment of desulfurization wastewater,Clostridium was the most abundant genus in the anaerobic reactor,which was also abundant in the anoxic and aerobic reactors.Clostridia was also detected to degrade organic pollutants.Blastocatella was the most abundant genus in the aerobic reactor,which was a kind of chemoheterotrophy microorganism.Genus Hyphomicrobium,which could degrade nitrogenous organic,was also detected in the process.In the anoxic reactor,the detected denitrification bacteria were Azoarcus,Paracoccus et al. |
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