Study On Operation Characteristics And Microbial Communities In An Up-flow ANAMMOX Reactor

A large number of nitrogen which come from domestic,industrial and agricultural wastewater are discharged into the natural water.Nitrogen pollution has posed a great threat to human health and the environment.The classical biotechnology has been widely applied in biological nitrogen removal process of wastewater.However,there are still many problems,such as high energy consumption,complex maintenance processes,inefficient and so on.Therefore,it would be particularly important for us to develop new nitrogen removal biotechnology.Anaerobic ammonium oxidation(ANAMMOX)process is a novel,efficient and energy saving wastewater nitrogen removal technology.ANAMMOX technology has received lots of attention since it was discovered.However,there are still several bottlenecks need to be solved,and the major challenges are the culture of the ANAMMOX sludge and the negative effects of the operational environment to bioreactor.The research investigated on the influence of inorganic carbon,temperature and organics on ANAMMOX process in anup-flow ANAMMOX reactor,the kinetics characteristics of cultured ANAMMOX bacteria were also analyzed.And microbial community structure of reactor was analyzed using high-throughput sequencing technology.In addition,the nitrosated-ANAMMOX integration process in the up-flow Anammox reactor was successful started up.The reactor was inoculated sludge from laboratory cultured mixed sludge,which contained some ANAMMOX bacteria.Different concentrations of inorganic carbon(IC)were added into the influent after the reactor was running steadily.The influence of IC on ANAMMOX process was studied by evaluating the nitrogen removal efficiency,and the best inorganic carbon concentration suitable for ANAMMOX process was investigated.The results suggested IC provided a suitable carbon source and played a catalytic role in the ANAMMOX process.Sufficient IC in influent was important to maintain ANAMMOX bacteria activity and stable nitrogen removal efficiency.The optimal ratio of IC/TIN was 0.4 in the influent for ANAMMOX process.A new reactor was started up with the influent IC/TIN of 0.4 and achieved nitrogen removal efficiency up to 1.04 kg-N·m-3-day-1 after 61 days stable operation.The ANAMMOX bacteria in the new reactor presented higher activity than that of the previous reactor.Temperature,organic matter,substrate concentration,pH and other environmental factors have an important impact on the anaerobic ammonium oxidation process.The influence of environmental factors on ANAMMOX process was analyzed by the experiment of continuous flow reactor combined with the sequencing batch experiment,which is realized by changing the operation parameters of the reactor and testing the activity of ANAMMOX bacteria.The results showed that temperature had a significant effect on ANAMMOX bacteria activity.It was very important to maintain a high temperature to obtain the high activity of ANAMMOX bacteria.There was substrata competition between the denitrification bacteria and ANAMMOX bacteria when organics exist in the influent.The half saturation constants for ammonium and nitrite of the ANAMMOX bacteria were 151.97 mg·L-1 and 42.59 g·L-1 respectively.The half inhibition constant for ammonium and nitrite of the ANAMMOX bacteria were 555.31 g·L-1 and 200.61 g·L-1 respectively.pH could influence ANAMMOX activity dramatically.The optimal pH was between 7.47?8.03.In order to study the relationship between the nitrogen removal efficiency and the microbial community structure,and the effect of organic matter on the microbial structure of the reactor,the microbial community structure of reactor was analyzed using high-throughput sequencing technology.The results show that the microbial community structure tended to be stable during the start-up of the ANAMMOX reactor.Proteobacteria and Planctomycete accounted for more than 40%total.The proportion of Planctomycete containing ANAMMOX bacteria increased gradually with the time,which was the main reason for the improvement of denitrification efficiency.And the ANAMMOX bacteria Candidatus Kuenenia category is dominated in reactor,its quantity ratio reaches 14%.Candidatus Brocadia was also found in reactor.The nitrosated-ANAMMOX integration process was successful started up in the up-flow Anammox reactor by inoculating nitrite sludge and increasing the dissolved oxygen(DO).The change of nitrogen removal efficiency in nitrosated-ANAMMOX integration reactor was studied,and the microbial community structure of the reactor was analyzed by high-throughput sequencing.The reactor was operated at 30? and DO 2 mg/L.During the start-up of reactor the nitrogen loading rate was 0.75 kg-N/m3/day,the average ammonium removal efficiency and the total nitrogen removal were 85%,80%respectively.The ammonia oxidizing bacteria Nitrosomonas together with the anaerobic ammonia oxidizing bacteria Candidatus Brocadia and Candidatus Kuenenia werreactor.Besides,some other bacteria like Denitratisoma also existed.e detected as the functional bacteria inIn this study,the effects of different environmental factors on ANANMMOX process were investigated by starting and operating the ANAMMOX reactor.The start-up and operating conditions of anaerobic ammonium oxidation process were determined,which can provide a theoretical basis for the actual engineering application.