Study On The Integration Of Methanogenesis,Denitrification And Anaerobic Ammonium Oxi-Dation In EGSB Reactor By Xuliang Qi

Tannery industry has become a heavy pollution industry in China. Wastewater discharged from tannery industry often contains large amounts of organic carbon, or-ganic nitrogen and ammonia, which have greatly increased disposal difficulty and cost. Effect nitrogen removal technology has been the key factor for tannery wastewater treatment. Some new type nitrogen removal technologies have been developed, such as anaerobic ammonia oxidation, short-rang denitrification. However, few studies were carried out in tannery wastewater. To exploit new type nitrogen removal tech-nologies in tannery wastewater, EGSB reactor was used to study the integration of methanogenesis with anaerobic ammonium oxidation and denitrification. After250days of running, the main results were as follows:(1) The EGSB reactor had a good treatment effect on NH4+-N, N03"-N, NO2--N and TKN. When the influent concentration of them was328mg/L,200mg/L,220mg/L and752mg/L, the removal efficiency could reach44%,83.7%,98.4%and71.6%re-spectively. The removal efficiency of TN could reach78.4%at last.(2) The EGSB reactor had a good treatment effect on COD. While average in-fluent COD concentration was3766mg/L, the reactor showed a good removal capaci-ty once started, and the removal efficiency could maintain80%after250days of run-ning. (3) Metagenomics methods study revealed a rich diversity of microorganisms in the EGSB reactor, including bacteria (87.9%), archaea (6.3%) and eukaryotic micro-organisms (5.3%). The reactor also had a large account of bacteria which had been reported that had methanogenesis ability, denitrification ability, anammox ability, and aerobic ammonia oxidation ability, and the relative abundances of them were4.15%,5.15%,2.14%and0.53%respectively. The maximum biomass in EGSB reactor was uncultured anaerobic hydrogen producing bacterium Candidatus Cloacamonas ac-idaminovorans (1.78%), and the maximum biomass of methane bacteria and denitri-fying bacteria were Methanosaeta thermophile (0.70%) and Thiobacillus denitrificans (0.31%) respectively. The maximum relative abundance of bacteria that had been re-ported had anammox ability were Rhodopirellula baltica (0.26%) and Pseudomonas aeruginosa (0.26%).(4) High throughput sequencing and BLAST analysis found a large account of microorganism, and most of them were uncultured. The biomass of denitrification was much larger than that of aerobic ammonia-oxidizing bacteria. Molecular cloning showed that all the AOB in the reactor were Nitrosomonas, and had a highest homol-ogy with Nitrosomonas europaea, which also proved by BLAST analysis.(5) qPCR research demonstrates:the relative abundance of nirS、nirK、nosZ and AOB-amoA genes was1.14%,0.21%,1.11%and0.08%respectively, which was con-sistent with the result of BLAST in trend.(6) Both chemical index analysis and microorganism research had demonstrated the integration of methanogenesis with anammox and denitrification. What’s more, the reactor had a good stability. So it might be a new way of denitrification in taanery wastewater.