Study On Start-up Of SHARON-Anammox Process And Its Microbial Community Characteristics

Traditional sewage treatment processes can not meet the increasingly stringent water emission standards due to their low efficiency on nitrogen removal,the large investment in infrastructure and high operating costs.Anaerobic ammonium oxidation(Anammox)is a novel,autotrophic and cost-effective process,compared to these traditional biological nitrogen removal processes.In this study,based on the Anammox process,pilot-scale SHARON-Anammox reactor was used to deal with urban domestic sewage.Starting strategies and stable operating conditions were explored.The variation laws of microbes activity and community structure in operation were also studied.The Anammox process was successfully carried o ut by using the pilot-scale SBBR reactor with effective volume of m3 in the condition of pH7.6?8.3 and temperature 25?32 ? for 95 days.The re mo val loading rate of TN reac hed to 0.40kgN/(m3·d),with the NH4+-N remo val rate of79.55%and NO2--N removal rate of 99.26%,and the ratio of ammonium removal,nitrite removal and nitrate increase was 1:1.37.0.23.The activity of HZO was positively correlated with the temperature change and the HZO activity on the filler was larger than that of suspended sludge.The batch test proved that the TN removal path in the reactor,Anammox plays a leading role and the removal rate is 0.103 kg-N(m3·d)-1.The microbial community structure was identified by the high-throughput sequencing,and found that Candidatus Kuenenia became a dominant species with an amount of 23.57%.The integrated SHARON-Anammox process was achieved successfully in corridor reactor with an effective volume of 60L by inoculating mixed AOB(Nitrosification bacteria)and AnAOB(Anammox bacteria)sludge with 12 ratio,under the condition of DO?0.1?0.2 mg/L and pH?7.8-8.3.The effluent TN was kept below 4mg/L and N RR was 0.018 kg·N(m3·d)-1 by control HRT at 27.2h.The activity of HZO and content of EPS was positively correlated with the NRR during the stable operation The dominant species in the system were Nitrosomonas,Candidatus Kuenenia and Denitratisoma.Then the integrated SHARON-Anammox process was successfully started at the ambient temperature in a pilot-scale oxidation ditch with the effective volume of 5.6m3.The average concentration of TN in effluent was 4.92mg/L,the TN removal rate was 78%and the NRR is 0.028 kg·N(m3·d)-1 by maintaining HRT at 15h and aeration ratio at 3:1.The SOUR rate increased with aeration time and aeration ratio,and SOUR rate of suspended sludge was larger than that of filler slud ge.The HZO activity of slud ge on filter in the no n-aeratio n area was higher than that in the aeratio n area and the suspended sludge.The filler at the bottom in the reactor was more favorable for the enrichment of Anammox bacteria.Batch test proved that nitrogen removal pathways in the system mainly consist of aerobic ammonium oxidation,anaerobic ammonium oxidation and denitrification reaction.The rate of different reactions changed with the different operating conditions.The nitrogen bacteria in the process of th e system mainly included Nitrosomonas,Candidatus Kuenenia,Nitrospira and Thermomonas and so on.The content of Candidatus Kuenenia in the upper and lower part of filter in non-aeration area,aeration area and in suspended sludge was4.03%,4.65%,0.05%,1.16%and 0.6%,respectively.The investigation of Anammox bacteria at differe nt regio nal locations in the reacto r can provide guidance for the layout and design of the filler in the SHARON-Anammox reactor.