Study On Treatment Of Wastewater With High Ammonia Nitrogen By New Combination Of Biofilm Reactor

In the production process of livestock and poultry breeding industry,petrochemical industry,pharmaceutical industry and other fields,a large amount of high concentration of ammonia nitrogen wastewater will be produced,among which the concentration of ammonia nitrogen in some wastewater will exceed 1000 mg/L,and the concentration of ammonia nitrogen in some production units of some industries will even exceed 10000 mg/L.High concentration ammonia nitrogen wastewater discharged into the water without treatment will cause eutrophication,which will cause great influence and harm to the receiving water body and human health.Although the existing physicochemical method has a good effect on the treatment of high ammonia nitrogen wastewater,it has a high energy consumption and is easy to produce secondary pollution.The biological treatment method has lower operation cost and better treatment effect for the wastewater with low concentration of ammonia nitrogen,but less effective treatment effect for the wastewater with high concentration of ammonia nitrogen.Heterotrophic nitrifying and denitrifying denitrifying bacteria?HN-AD?have the advantages of strong tolerance to extreme environment?high ammonia nitrogen,low temperature?and good denitrification effect.However,the lack of efficient HN-AD strain resources and the competition among the microflora in the biofortified system limit the application of HN-AD strain in practical engineering.In this study,HN-AD was isolated from the biogas slurry of pig farm.HN-AD bacteria combined with biofilm reactor was used in denitrification of high ammonia nitrogen wastewater.With the help of high-throughput sequencing technology and SEM characterization analysis method,the microbial diversity on the biofilm was discussed,and the diversity and function of the main HN-AD bacteria in the biological enhancement process were analyzed,providing theoretical basis and technical support for the application of HN-AD bacteria.The main research contents and conclusions are as follows:?1?HN-AD mixed bacteria that can tolerate high ammonia nitrogen can be obtained from the domestication and enrichment of biogas slurry in pig farm.When the concentration of ammonia nitrogen was 400mg/L,the average removal rates of ammonia nitrogen and total nitrogen were 100%and 79.05%,respectively.Diversity analysis showed that HN-AD was dominated by Acinetobacter,Comamonas and Pseudochrobactrum.?2?when the ammonia nitrogen concentration increased to 400mg/L,the removal rates of NH₄⁺-N,TN and COD in the biological rotary table system were 54.54%,46.05%and 62.19%,respectively.After biological enhancement,the average removal rates of NH₄⁺-N,TN and COD were 83.09%,58.96%and 73.92%,respectively.The removal rates of NH₄⁺-N,TN and COD were47.41%,44.93%and 57.26%,respectively.After biological enhancement,the removal rates of NH₄⁺-N,TN and COD were stable at 78%,65.95%and 73.53%.The diversity analysis of biofilm before and after biofortification showed that Acinetobacter,the dominant tobacter in the biorotary plate,increased from 0.01%to 18.56%after biofortification.However,the abundance of Diaphorobacter playing a major role in the contact oxidation pool ranged from 9.1%to 10.3%,and the new tobacter Acinetobacter was found,with a richness of 2.2%.?3?after parameter optimization,when HRT=24h,COD/NH₄⁺-N=10 and the rotary table linear velocity is 15m/min,it is the optimal parameter of the biological rotary table.The contact oxidation pool is the optimal parameter when HRT=24h.?4?treatment of wastewater with high ammonia nitrogen under optimal conditions.When the average concentration of COD,NH₄⁺-N and TN in the influent water was 5911.8mg/L,572.47mg/L and 608.66mg/L,respectively,the average removal rate of COD,NH₄⁺-N and TN in the combined process was 97.5%,97.73%and 84.6%,respectively.The average concentrations of COD,NH₄⁺-N and TN in effluent were 147.5mg/L,13.2mg/L and 93.34mg/L,respectively.After treatment,it meets the level-iii standard of urban sewage treatment plant sewage discharge?GB 18918-2002?.