Effects of C/N ratio on nitrous oxide production from nitrification in a laboratory-scale biological aerated filter reactor.
Emission of nitrous oxide (N2O) during biological wastewater treatment is of growing concern. This paper reports findings of the effects of carbon/nitrogen (C/N) ratio on N2O production rates in a laboratory-scale biological aerated filter (BAF) reactor, focusing on the biofilm during nitrification. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and microelectrode technology were utilized to evaluate the mechanisms associated with N2O production during wastewater treatment using BAF. Results indicated that the ability of N2O emission in biofilm at C/N ratio of 2 was much stronger than at C/N ratios of 5 and 8. PCR-DGGE analysis showed that the microbial community structures differed completely after the acclimatization at tested C/N ratios (i.e., 2, 5, and 8). Measurements of critical parameters including dissolved oxygen, oxidation reduction potential, NH4+-N, NO3--N, and NO2--N also demonstrated that the internal micro-environment of the biofilm benefit N2O production. DNA analysis showed that Proteobacteria comprised the majority of the bacteria, which might mainly result in N2O emission. Based on these results, C/N ratio is one of the parameters that play an important role in the N2O emission from the BAF reactors during nitrification.
Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, China E-mail: hq0908@126.com.
Qiang
Q
He
Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, China E-mail: hq0908@126.com.
Yinying
Y
Zhu
Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, China E-mail: hq0908@126.com.
Leilei
L
Fan
Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, China E-mail: hq0908@126.com.
Hainan
H
Ai
Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, China E-mail: hq0908@126.com.
Xiaoliu
X
Huangfu
Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, China E-mail: hq0908@126.com.
Mei
M
Chen
D000641:Ammonia / Q000032:analysis; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D002244:Carbon / Q000032:analysis*; D004275:DNA, Ribosomal / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D005374:Filtration / Q000295:instrumentation*; D007753:Laboratories; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis*; D009609:Nitrous Oxide / Q000032:analysis*; D010100:Oxygen / Q000032:analysis; D020560:Proteobacteria / Q000378:metabolism; D012995:Solubility; D013997:Time Factors; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000382:microbiology
D000641:Ammonia; D002244:Carbon; D004275:DNA, Ribosomal; D009584:Nitrogen; D009609:Nitrous Oxide; D010100:Oxygen; D062065:Wastewater