Studies On The Structure Of Microoganisms In Anaerobic Ammonium Oxidation Pilot Reactor

With the development of industry,the pollution of nitrogen-containing sewage is increasing steadily.The traditional nitrification-denitrification process has been unable to meet current treatment demands due to its low nitrogen removal efficiency.The anaerobic ammonia oxidation and its combination process are becoming popular in wastewater treatment studies for the following advantages as small occupation area,no additional organic carbon source and no secondary pollution.But anaerobic ammonia oxidation bacteria grow slowly with 11 days of double time,and that it is sensitive to its growing environment,especially for organic is found having serious impact on the denitrification performance.These problems seriously restrict the development of anaerobic ammonia oxidation process.To provide a reference for the improvement of the nitrogen removal ability and the enrichment of Anammox bacteria in the reactor,the microbial community structure was analyzed in the experimental reactor of anaerobic ammonia oxidation in this study.The main results are as follows.?1?The bacteria of anaerobic ammonia oxidation pilot reactor was analyzed by PCR-DGGE,and the microbial diversity was gradually decreased during the start-up process of nitrification.The Richness index was reduced from 63.63%to 33.33%and Shannon index was reduced from 2.45 to 2.28.The microbial diversity increased in the anaphase of anaerobic ammonia oxidation pilot reactor when inoculated activated mud added.The index remained at 67%of Richness and 2.6 of Shannon.The essential process of nitrosation start-up phase is of the enrichment of AOB bacteria and the inhibition of NOB bacteria.The total microbial species gradually reduced and AOB became the dominant bacteria.These results confirmed by PCR-DGGE analysis.?2?qPCR analysis indicated that the AOB bacteria increased from 1.1×10¹⁰copies/mL to 3.2×10¹¹ copies/m L and NOB bacteria reduced from 1.1×10¹⁰ copies/m L to 1.2×10⁹copies/mL in the nitrosation start-up process.Nitrosation AOB bacteria content in the process was two orders of magnitude higher than NOB bacteria content.The increasing of AOB bacteria and the decreasing of NOB bacteria suggested the increasing of nitrification capacity in anaerobic ammonia oxidation reactor.In the combined Nitrosation-Anammox nitrogen removal stage,Anammox bacteria content increased by two orders of magnitude and NOB bacterial content decreased by two orders of magnitude.The increased Anammox bacteria indicated the improved anaerobic ammonia oxidation capacity.?3?16S rDNA sequencing showed that?-Proteobacteria and?-Proteobacteria are the dominated anaerobic ammonia oxidation bacteria.Anammox bacteria were enriched in the maximal degree at the C/N=0.4 stage.With the increasing of C/N value,the Anammox bacteria were gradually decreased and heterotrophic denitrifying bacteria were gradually increased.It is indicated that C/N=0.4 is the optimum organic content for the growth of Anammox bacteria.?4?Fluorescence quantitative PCR?qPCR?analysis was also used to explore the effects of organics on the denitrification of anaerobic ammonia oxidative bacteria.The results showed that bacteria contents of Anammox bacteria was 1.92×10¹⁰ copies/m L and DB bacteria was 1.57×10⁹ copies/mL at the stage of C/N=0,and the denitrification ability was mainly provided by Anammox process.With the increasing of C/N,Anammox bacteria were constantly inhibited,and the heterotrophic anti-nitrification bacteria are enriched.At the point of C/N=2.0,the content of Anammox was 3.18×10⁹ copies/mL and the amount of DB bacteria was 3.74×10¹⁰copies/mL.This result indicated the complete inhibition of Anammox activity and nitrogen removal capacity of the anti-nitrifying bacteria.?5?High-throughput sequencing analysis of bacteria structure in SBR reactor showed that the anaerobic ammonia oxidation denitrification bacteria community changed dramatically with the increase of organic carbon content in the water.With the increased of C/N value from 0 to 2.0 in the process of deformation,Proteobacteria increased from 18.94%to 81.35%and Planctomycetes decreased from 7.49%to0.07%in the total bacteria.While Nitrospirae reached a maximum of 0.39%at the C/N=0.8 point?only 0.01%in other phases comparatively?.With the increase of organic content,the denitrification capacity of anaerobic ammonia oxidation reactor was gradually transitioned from Anammox to denitrifying,which was consistent to the results of high-throughput sequencing.