Effect of free nitrous acid (FNA) on microorganism community structures of A2O sludge
MA Lin-na1, LIU Wen-long2, ZHANG Qiong1, PENG Yong-zhen1,2
1. National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China;
2. State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
In order to assess the feasibility of achieving nitritation in the anaerobic/anoxic/oxic (A2O) system through the strategy of free nitrous acid (FNA) sludge treament,the activities of ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) activities was studied.Besides,the variations of nutrient removal performance and microorganism community structures in the A2O reactor after long-term FNA sludge treatment were investigated.Results showed that the activities of AOB and NOB decreased by 60% and 86% respectively after the sludge subjectd to FNA treatment at 1.12mg HNO2-N/L for 3h.The average effluent concentrations of NH4+-N,NO2--N and NO3--N in the A2O system were 12.76,1.56 and 7.82mg/L respectively.The nitrite accumulation rate (NAR) was around 20%,indicating that nitritation in the A2O system was not achieved by the FNA sludge treament.Furthermore,High-throughput sequencing and qPCR results showed that AOB abundance was greatly decreased from 2.05×108copies/gVSS to 3.96×105copies/gVSS and the ammonia oxidation process was negatively affected.In addition,Nitrobacter and Nitrospira were also inhibited,while Nitrotoga accounted for 1.66% of total sequences,for which the nitritation in the A2O system was not achieved by FNA sludge treatment strategy.
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