| Autotrophic nitrogen removal process based on ANAMMOX is one of the most efficient processes for nitrogen removal. Compared with nitrification-denitrification process, it can save 25% of oxygen and 100% of organic carbon, reagent for pH adjustment and reduce the production of wasted sludge. In this paper, the cultivation, enrichment and identification of AnAOB, dynamic characteristics, influences and nitrogen removal capacity of nitritation-ANAMMOX process were investigated. Besides, the achievement, population of biomass, influences and mechanism of autotrophic nitrogen removal in single SBR were studied and discussed. The main results were showed as follows:1. Inoculated with common anaerobic sludge,98.15% ammonium removal efficiency and 99.56% nitrite removal efficiency were gained, operated under the condition that the temperature was 40-41℃, HRT was 1.3d, pH was 8.25-8.5 and light is kept away, in anaerobic rotating biological contactor (AnRBC) after 142 days' operation, which indicated that AnRBC was suitable for ANAMMOX bacteria to enrich. The highest volume removal rate and surface removal rate reached 0.88kg N·m-3·d-1 and 17g N·m-2·d-1 after 480 days'operation by shortening HRT, elevating influent concentrations and adding influent flow rates. The biomass was identified as C. Kuenenia stuttgartiensis of AnAOB by FISH and PCR analysis.2. One day was most suitable HRT for nitrogen removal using ANAMMOX process in AnRBC. Effect of different organic substrate concentration on nitrogen removal of ANAMMOX process was investigated through batch and continuous experiments. The maximum ammonium oxidizing rate reached 0.189kg NH4+-N kg-1 VSS d-1 under autotrophic conditions. The ammonium oxidizing rate fell below to 0.05 kgNH4+-N·kg-1VSS·d-1 when the concentration of organic substrate was more than 70 mg L-1. It was indicated that high ratio of N/C system was more liable for TN removal than a completely autotrophic system through continuous experiments, due to the coactions of denitrifying bacteria and ANAMMOX bacteria. The average TN removal efficiency reached 96.59% when the COD was 50 mg L-1. When the concentration of organic substrate was high enough, denitrification became more and more dominant and ANAMMOX weakened.3.The ANAMMOX process was affected by both ammonium and nitrite concentrations, therefore, the dynamic equation can be desscribed by Haldance model. The parameters were obtained through batch experiments·KS,NH4+=180.73mg/LKI,HN4+= 976.91mg/L,KS,NO2-=46.23mg/L; KI,NO2-=116.78mg L-1; qmax=0.085 mg NH4+-N·mg MLSS-1·-h-1.4. When the temperature of the AnRBC was decreased from 40-41℃to 35℃, filamentous bulking happened, which led to the decrease of the ammonium removal efficiency from 90% to 50% below. The filamentous sulfur bacteria were identified, and the coactions of sulfur reducing bacteria and filamentous sulfur bacteria were responsible for the sludge washing. After the temperature was changed back and the organics was removed from the influent, the filamentous bulking was prevented effectively after 1 month.5. Inoculated with common aerobic sludge, more than 80% of nitrite accumulated efficiency was gained in an SBR after 20 days'operation under conditions of t=30-31℃, pH=7.8-8.3, DO=0.8-1.0mg L-1. The dynamic equation of nitritation can be described by Monod equation, the dynamic parameters were obtained through experiment were:vmax=13.05 mg NH4+-N·g-1 MLSS·h-1, Ks=21.98 mg NH4+-N·L-6. The effect of organic matter concentration on nitritation showed that the ammonium oxidizing rate and nitrite accumulated efficiency decreased at high organic matter concentration, and TN losses were observed due to the simultaneous denitrification. The dynamic parameter of vmax first increased and then decreased with the increase of the organic matter concentration and the maximum vmax was 58.72 mg NH4+-N·g-1 MLSS·h-1 at the C/N of 0.6.7. The ANAMMOX process was operated steadily using nitrite from SBR effluent as electron acceptor, the ratio of nitrite to ammonia consumed was between 1.0 to 1.2. The ammonium, nitrite and TN removal efficiency reached 86-100%,97-99.7 %and 86-94%, respectively, and the volume removal rate of TN reached 0.5 kg m-3 d-1. In this paper, combined nitritation and ANAMMOX process for nitrogen removal saved 0.6 kg·m-3·d-1 of oxygen consumed and 1.2 kg·m-3·d-1 of organic matter, respectively, compared to nitrification-denitrification process.8. After the dissolved oxygen concentration was decreased (from 0.9±0.1 to 0.4±0.1 mg L-1) and the aeration time was elevated (from 330 to 450 min per cycle) during operation of nitritation in SBR,79.8% of TN removal efficiency and 0.485 kg N m-3 d-1 of maximum nitrogen removal capacity and 0.154 kg N kg-1 MLVSS d-1 of nitrogen removal rate were obtained. During single-cycle the nitrite first increased and then decreased,60 min at its'maximum; nitrate were basically unchanged in the first 60min, followed by a gradual increment; ammonia and TN almost reduced tending to straight line.9. By the application of FISH analysis, bacteria belonging to the genus Nitrosomonas were identified as the dominant population. AnAOB of Candidatus Brocadia anammoxidans and/or C. Kuenenia stuttgartiensis and very small amounts of Nitrospira spp were also detected. A maximum anaerobic ammonium oxidation activity of 6.71 mg NH4+-N·g-1 VSS·h-1, aerobic ammonium oxidation activity of 10.13 mg NH4+-N·g-1 VSS·h-1 but no nitrite oxidation activity was detected through batch experiments.10. The ratio of nitrate produced to ammonia consumed (0.09) was lower than that achieved with the CANON process during 60 days'operation, which revealed the occurrence of autotrophic denitrification. Through mass-balance analysis, (88.1±2.6)% and (9.4±1.2)% of the influent ammonium was converted to dinitrogen gas and nitrate, respectively. According to stoichiometry ammonium was mainly removed (72.3±9.2) through coaction of aerobic ammonium oxidation and anaerobic ammonium oxidation, and 25.5% was converted to dinitrogen gas through aerobic ammonium oxidation and denitrification by AOB of Nitrosomonas.
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