Study On Nitrogen Removal Performance Of Nitrosification In SBR-ANAMMOX In Compound UASB Process

Nitrogen pollution of aquatic system is becoming severely and the nitrogen removal technology of waste water has accordingly developed from traditional nitrification-denitrification process to the application of new processes such as short-cut nitration-denitrification and simultaneous nitrification-denitrification. However, limitation of too much organic carbon adding and high cost exists in these processes in the treating of large amount of wastewater of low carbon and high ammonium-nitrogen such as landfill leachate, reject water, coking water and wastewater from fertilizer plant of nitrogenous products. Anaerobic ammonia oxidation technology has much advance in the treating of this kind of wastewater for no organic carbon requirement and has become one of the hottest research focuses in wastewater treating field. This project aimed to discuss the nitrogen removal performance of nitrosification in SBR-ANAMMOX in compound UASB combined process, with ANAMMOX technology as the core, and to promote the application of ANAMMOX technology in wastewater treatment field in China.Simulate wastewater of low carbon-nitrogen ratio was treated in this study. Nitrosification matching to ANAMMOX experiment was done in SBR reactor and ANAMMOX experiment was done in compound UASB reactor. Based on these studies, study on the nitrogen removal performance of the combined process was conducted.The nitrosification action in SBR was started with of sequence of inflow (instant)-aeration (4h)-sedimentation and drainage (2h)-standby (2h) and the aeration was conducted continuously at low flow. The reactor was started up successfully after49d, and the removal rate of NH4+-N and accumulation rate of NO2-N were above90%and80%respectively. The study shows that the preferable working condition for nitrosification in SBR was as follows:DO=1.0mg/L, temperate around28centigrade degree, pH=7.5-8.0, CODCr concentration below150mg/L. Conducted at this condition, the NH4+-N removal rate and NO2--N accumulation rate of the reactor were above90%and75%respectively. For the NH4+-N concentration of250mg/L, the preferable working sequence for ANAMMOX matching nitrosification was inflow (instant)-aeration (3.5h)-sedimentation and drainage (2h)-standby (2.5h).The ANAMMOX action in compound UASB was started at the condition of NH4+-N concentration of60mg/L, NH4+-N/NO2--N=1:1.32, sodium bicarbonate as sole carbon resource, HRT=48h, temperature around30centigrade degree. The reactor was started up successfully136d later and the removal rates of NH4+-N and NO2-N were both above49%. The study shows that the TN volume load of the reactor can be improved from0.069kg-m3·d-1to0.464kg·m-3·d-1through raising NH4+-N and NO2--N concentration in the influent and shortening HRT of the reactor, and the TN removal rate retained beyond50%. The preferable working condition of ANAMMOX action in compound UASB reactor was as follows:temperature around30centigrade degree, influent pH=7.5-8.5, HRT=24h, DO removal in the influent, sodium bicarbonate concentration within1.5-2.0g/L, CODCr concentration below60mg/L. At this condition, TN removal rate of the reactor retained around70%.The nitrosification in SBR reactor and ANAMMOX in compound UASB reactor matched to each other after a phrase of adjustment and adaptation, and the nitrosification in SBR-ANAMMOX in compound UASB combined process was joined and conducted stably. The nitrogen removal effect of this combined process performed well, and average removal rates of NH4+-N and TN were88.52%and71.36%separately.The results of this study show that the nitrosification in SBR-ANAMMOX in compound UASB combined process can solve the problem of large amount of organic carbon adding and its consequent problems of high running cost and secondary pollution caused of the traditional nitrification-denitrification process, and perform preferable nitrogen removal effect in the treating of low carbon-nitrogen ration wastewater, especially wastewater of low carbon and high ammonium-nitrogen. It is reasonable to adopt this process in the low cost treating of this kind of wastewater.