High C∶N ratio in the wastewater limits biological nitrogen removal(BNR),especially in anammox based technologies.The present study attempts to improve the COD tolerance of the BNR process by associating methanogens with nitrogen removing bacterial(NRB)populations.The new microbial system coined as'Methammox',was investigated for simultaneous removal of COD(C)and ammonia(N)at C∶N ratio 1.5∶1 to 14∶1.The ammonia removal rate(11.5 mg N/g VSS/d)and the COD removal rates(70.6 mg O/g VSS/d)of Methammox was close to that of the NRB(11.1 mg N/g VSS/d)and the methanogenic populations(77.9 mg O/g VSS/d),respectively.The activities established that these two populations existed simultaneously and independently in'Methammox'.Further studies in biofilm reactor fetched a balanced COD and ammonia removal(55％-60％)at a low C∶N ratio(≤2∶1)and high C∶N ratio(≥9∶1).The population abundance of methanogens was reasonably constant,but the nitrogen removal shifted from mixotrophy to heterotrophy as the C∶N ratio shifted from low(C∶N≤2∶1)to high(C∶N≥9∶1).The reduced autotrophic NRB(ammonia-and nitrite-oxidizing bacteria and Anammox)population at a high C∶N ratio was compensated by the fermentative group that could carry out denitrification heterotrophically.The functional plasticity of the Methammox system to adjust to a broad C∶N ratio opens new frontiers in biological nitrogen removal of high COD containing wastewaters.

Shaswati Saha;Rohan Gupta;Shradhanjali Sethi;Rima Biswas

Academy of Scientific and Innovative Research(AcSIR),CSIR-Human Resource Development Centre(CSIR-HRDC),Ghaziabad Uttar Pradesh-201002,India;Wastewater Technology Division,CSIR-National Environmental Engineering Research Institute,Nagpur Maharashtra-440020,India

环境科学与工程前沿

[1]Shaswati Saha;Rohan Gupta;Shradhanjali Sethi;Rima Biswas-.Enhancing the efficiency of nitrogen removing bacterial population to a wide range of C∶N ratio(1.5∶1 to 14∶1)for simultaneous C&N removal)[J].环境科学与工程前沿,2022(08):51-65

BNR,NRB,Methammox,fetched,mixotrophy,heterotrophy,heterotrophically

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