Research And Application Of Microbial Bioaugmentation Technology In Nitrogen Removal Of Livestock Wastewater

Livestock wastewater is a typical organic wastewater with high-concentration,due to its large amount of discharge and high concentration of pollutants,it causes great harm to the environment..Therefore,it is very important to improve the efficiency of the sewage treatment system.The research of bioaugmentation technology has now become a hotspot in the field of environmental protection.However,the application of bioaugmentation technology to the treatment of high-concentration livestock wastewater is still an exploratory stage in China.In view of this situation,the objectives of this study is to screen the functional strains,which were efficient,easy to survive,easy to form biofilm.Then these strains were used to enhanced the Biological Aerated Filter?BAF?and Sequencing Batch Reactor?SBR?system,exploring the operation parameters of the treatment process,in order to increase the treatment efficiency.Research indicates:1.Twenty strains of heterotrophic nitrifying aerobic denitrifying bacteria were isolated and screened from the sediment samples collected from the livestock wastewater treatment wetland by specific medium,and the TN removal efficiency of two strains of A10 and A12 exceeded 80%within 24 hours.The gene sequences were compared with NCBI database,and they were identified as Pseudomonas guariconensis and Pseudomonas stutzeri,respectively.2.After the BAF system was enhanced by the joint bacteria strains of A10 and A12,the removal rate of pollutants was improved.The average removal rates of CODcr,NH₄⁺-N and TN were 76.21%,64.56%and 64.45%,respectively,which increased by 11.72%,20.20%and 24.14%compared with the control group.When the gas-water ratio reached 10:1,the removal rate of CODcr was highest,with an average removal rate of 76.36%.When the gas-water ratio reached15:1,the removal efficiency of NH₄⁺-N and TN was highest,with an average removal efficiency of 73.45%and 75.34%.When the hydraulic retention time?HRT?was 16h,the removal rate of CODcr was highest,with an average removal rate of 76.35%and76.43%.When HRT was 16h,the removal rates of NH₄⁺-N and TN were highest,with the average removal rates of 83.35%and 84.36%.3.After the SBR system was enhanced by the joint bacteria strains of A10 and A12,the removal efficiency of pollutants in system was significantly improved after stabilization.Compared with the control group,the removal rates of CODcr,NH₄⁺-N,TP and TN in the enhanced group were increased by 9.92%,12.51%,3.4%and 22.54%,respectively.When the aeration rate was 400 L/min/m³,the removal rates of CODcr,NH₄⁺-N and TN reached the highest,with an average of 91.82%,89.2%and 71.32%,respectively.When the aeration rate was 300 L/min/m³,the removal rates of TP were the highest,with an average of 58.87%.The dosage of sodium acetate was 400mg/L,and the removal rates of CODcr,NH₄⁺-N and TN were the highest in SBR,with the average removal rates of93.73%,94.80%and 89.40%.