Environmental Science and Pollution Research

, Volume 22, Issue 11, pp 8163–8173 | Cite as

Direct emissions of N2O, CO2, and CH4 from A/A/O bioreactor systems: impact of influent C/N ratio

  • Yangang Ren
  • Jinhe Wang
  • Li Xu
  • Cui Liu
  • Ruiqiang Zong
  • Jianlin Yu
  • Shuang LiangEmail author
Research Article


Direct emissions of N2O, CO2, and CH4, three important greenhouse gases (GHGs), from biological sewage treatment process have attracted increasing attention worldwide, due to the increasing concern about climate change. Despite the tremendous efforts devoted to understanding GHG emission from biological sewage treatment process, the impact of influent C/N ratios, in terms of chemical oxygen demand (COD)/total nitrogen (TN), on an anaerobic/anoxic/oxic (A/A/O) bioreactor system has not been investigated. In this work, the direct GHG emission from A/A/O bioreactor systems fed with actual sewage was analyzed under different influent C/N ratios over a 6-month period. The results showed that the variation in influent carbon (160 to 500 mg/L) and nitrogen load (35 to 95 mg/L) dramatically influenced pollutant removal efficiency and GHG production from this process. In the A/A/O bioreactor systems, the GHG production increased from 26–39 to 112–173 g CO2-equivalent as influent C/N ratios decreased from 10.3/10.7 to 3.5/3.8. Taking consideration of pollutant removal efficiency and direct biogenic GHG (N2O, CO2, and CH4) production, the optimum influent C/N ratio was determined to be 7.1/7.5, at which a relatively high pollutant removal efficiency and meanwhile a low level of GHG production (30.4 g CO2-equivalent) can be achieved. Besides, mechanical aeration turned out to be the most significant factor influencing GHG emission from the A/A/O bioreactor systems.


Greenhouse gases Biological sewage treatment A/A/O bioreactor Influent C/N ratio Removal efficiency Mechanical aeration 



This work was supported by the Program for New Century Excellent Talents in University (No. NCET-10-0554) and the National Natural Science Foundation of China (No. 21177075, 41305124, and 21007032).


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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Yangang Ren
    • 1
  • Jinhe Wang
    • 2
  • Li Xu
    • 1
  • Cui Liu
    • 3
  • Ruiqiang Zong
    • 4
  • Jianlin Yu
    • 1
  • Shuang Liang
    • 1
    Email author
  1. 1.Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and EngineeringShandong UniversityJinanPeople’s Republic of China
  2. 2.School of Municipal and Environmental EngineeringShandong Jianzhu UniversityJinanPeople’s Republic of China
  3. 3.Department of Mathematics and StatisticsTexas Tech UniversityLubbockUSA
  4. 4.Department of Environmental EngineeringTexas A&M UniversityKingsvilleUSA

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