Isolation Of Acinetobacter With Completely Aerobic-denitrification And Its Application In The High-strength Ammonium Nitrogen Wastewater Treatment

The high-strength ammonium nitrogen wastewater brings about serious water pollution due to its characteristics of a continuously high discharge,and notable treatment difficulties.Biological nitrogen removal method for treating high-strength ammonium wastewater has been widely accepted as a more convenient,more cost-effective and cleaner method than physicochemical method,in which nitrification and denitrification bacteria constitute the main microbial community with nitrogen removal function.However,the efficiency of traditional nitrification and denitrification bacteria for high-strength ammonium wastewater was suppressed owing to the nutrient metabolism characteristics of its slow growth,long generation cycle,and low biomass concentration,which leads to the paralyzed performance of nitrogen removal process.Thus,in order to break through the technology bottleneck of traditional nitrification and denitrification bacteria and expand the application field of biotechnology,this article is focused on certain novel completely aerobic-denitrification strains with advantageous of high-strength ammonia tolerance and high nitrogen removal efficiency,which are separated from actual high-strength ammonium wastewater.It is investigated to the performance of completely aerobic-denitrification strains to actual high-strength ammonium wastewater treatment.The main results were showed as follows:1.The mixed culture TA-1 with characteristics of aerobic-denitrification function and high-strength ammonia tolerance were successfully enriched.The cell suspension samples were collected from livestock and poultry biogas slurry of a pig breeding enterprise in Chongqing to screen TA-1 bacteria through continuous transmission and domestication process.The nitrogen removal efficiency of TA-1 were investigated by factor experimental designs with a single nitrogen source and multiple nitrogen sources coexisting.The results were showed that the ammonium nitrogen removal rate could reach 94.5%after 108 hours of cultivation when the ammonium nitrogen substrate concentration was 400 mg/L under the single nitrogen source condition.In addition,under the multiple nitrogen sources conditionTA-1 would preferentially utilize nitrate nitrogen,and the following was ammonium nitrogen and nitrite nitrogen.Finally,in order to clarify the microbial community of TA-1,the biodiversity during the continuous transmission and domestication process was analyzed.The results indicated that the microbial structure gradually stabilized after acclimatization under high ammonium nitrogen conditions.The dominant bacteria genus were Acinetobacter and Unclassified f Brucellaceae.2.A certain completely aerobic-denitrification strain was successfully filtered.The strain was identified as Acinetobacter and named TAC-1,which was confirmed as an aerobic denitrification strain through investigation for nitrogen removal characteristics of TAC-1 on different nitrogen sources..Furthermore,the metabolic pathway of TAC-1 was deduced by quantitative analysis of potential enzymes and genes of NR and NiR.The results suggested that the genes expressed in TAC-1 metabolic pathway were mainly narG,nirS and nirK.According to the differences in gene expression sequence,enzyme gene concentrations and enzyme protein type under different nitrogen sources,the potential metabolic pathway of TAC-1 was NH₄⁺?NH₂OH?NO₂^-?NO₃^-?NO₂^-?N₂O?N₂.3.The optimal growth conditions of TAC-1 were successfully achieved.A single factor optimization experiment in ammonium nitrogen substrate concentration at 400 mg/L and C/N ratio at 10 was designed and carried out.The results showed that the ammonium nitrogen removal efficiency of TAC-1 reached 98.7%,when the carbon source type is sodium succinate,C/N is 10,the rotation speed is 150 r/min,and the OD₆₀₀ value of TAC-1reaches 2.266.In addition,the in this article,the adaptabilities of TAC-1 to extreme environments such as low temperature,high salt,and high ammonia nitrogen was investigated.It was found that TAC-1 could maintain high ammonium nitrogen removal efficiency?above 90%?even in the extreme environments of a maximum salinity tolerance at 2%,a maximum ammonium nitrogen concentration tolerance at 800 mg/L,and low temperature tolerance of 5?.4.The performance of TAC-1 on actual high-strength ammonium wastewater treatment was investigated.The chemical and pharmaceutical wastewater,livestock and poultry farming wastewater and landfill leachate were selected as the experimental objects,and each wastewater treatment experiment processed 120 hours.The results demonstrated that the ammonium nitrogen and total nitrogen removal efficiencies of chemical and pharmaceutical production wastewater raw water?921.3mg/L?and physicochemical effluent?593.2 mg/L?were 68.7%and 61.6%,and 57.2%and 59.3%,respectively.Then,the maximum ammonium nitrogen and total nitrogen removal efficiencies of livestock and poultry breeding biogas slurry?286.4 mg/L?was 74.8%and 71.3%,respectively.At last,the maximum ammonium nitrogen and total nitrogen removal efficiencies of the landfill leachate?266.8mg/L?was 80.2%and 68.4%,respectively.