The Performance And Microbial Diversity Of Novel HABR On CANON Process

Completely autotrophic nitrogen removal over nitrite(CANON)process was a kind of novel biological nitrogen removal process,including the nitrification and Anammox reaction process.Compared with the conventional biological nitrogen removal process,CANON process can save those issues that high oxygen consumption,adding additional organic carbon source,high operating cost,and repeated pollution.However,there are still some challenges in this process,such as the long start-up period,Long-term stable operation,and limit to the high ammonia nitrogen wastewater treatment.Thus,the novel hybrid anaerobic baffled reactor(HABR)was adoptted in this study,to research on the feasibility of CANON process applied in domestic sewage treatment.The main contents were as follows: rapid start-up of CANON process,long-term stable operation,the pattern of nitrogen removal,corresponding microbial activity,characteristics and community structure.The novel HABR was derived from anaerobic baffled reactor(ABR),indicating hydroformylation silk fiber as filler added in ABR reactor.Thus,the novel HABR has not only the advantages of ABR-low sludge yield,without mechanical agitation and low operating cost,but also the advantages of membrane reactorlong biological residence time.This study based on the novel HABR,and dividing into three phases as follows:In the first phase,CANON process started up.Under the following experimental conditions: temperature(30±2?)and p H(7.7±0.2),the reactor was inoculated with activated sludge and operated by gradually decreasing HRT.and investigated the stable operation of the reactor,and the influence of NH4+-N concentration on the process:(1)The quick start-up process was successfully achieved by the continuously operation within 89 days,and the reactor could stabilize over 187 days.The average concentration of effluent NH4+-N and TN were below 2mg/L and 10mg/L respectively,the average removal efficiencies of NH4+-N and TN reached above 96% and 83% respectively,and a NRR of 0.15 kg/(m3?d)was obtained.(2)During the stable phase,the concentration of NH4+-N and TN gradually declined along the reactor.The highest nitrogen removal efficiency of ammonia occurred in Compartment 1,the fluctuation of p H is closely related to DO.The change of conductivity and MLSS has a positive correlation with NH4+-N concentration.(3)By the change of NH4+-N concentration in influent,it was confirmed the novel HABR has a good performance to treat domestic sewage treatment with the NH4+-N concentration of 20~85mg/L.In the second phase,the functions of microbial activity and characteristics in the CANON reactor were studied.(1)After startup,sludge formed different colors among various compartments.The sludge were khaki in the first three compartments,while Tan sludge in other compartments(2)It was confirmed that bioactivity of Aer AOB and An AOB in Compartment 1 were much higher,by those batch experiments of CANON and Anammox.(3)SEM showed that enriched bacteria of AOB and An AOB coexisted in the reactor.(4)FISH microbiological analysis showed that An AOB was in the inner biofilm,while AOB was in the outer biofilm.In the second phase,community structure in the biofilm of each compartment was analyzed by PCR and high throughput pyrosequencing.(1)The DNA samples in the CANON reactor were studied by PCR amplification.Clear bands were presented in gel electrophoresis,indicating AOB and An AOB coexisted in each sample.(2)The high throughput pyrosequencing result showed that microbial diversity was extremely high in the reactor.The highest species richness was in Compartment 1.(3)Proteobacteria predominated in each sample.Two genus of AOB(Nitrosococcus,Nitrosopumilus),two genus of An AOB(Candidatus Brocadia,Candidatus Jettenia),one genus of NOB,and ten genus of denitrifying bacteria were detected.It indicated that AOB,An AOB,NOB and denitrifying bacteria could coexist in the one reactor.AOB and An AOB were function microorganisms to achieve nitrogen removal.