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 w...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.展开更多
基金The authors are grateful to the Director,CSIR-NEERI,Nagpur,India,for his guidance.Authors acknowledge the efforts taken by Knowledge Resource Centre,CSIR-NEERINagpur,India,for plagiarism check of the article using iThenticate software.SS and RG acknowledge the financial assistance granted for the SRF(F 2-2/2001,SA-1)JRF by University Grants Commission(UGC)and Council of Scientific and Industrial Research(CSIR),India(31/016(0130)2018-EMR-I),respectively。
文摘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.
