title: Nitrous oxide emissions from an aerobic granular sludge system treating low-strength ammonium wastewater.
abstract: Aerobic granular sludge is a promising technology in wastewater treatment process. Its special microorganism structure could make the emissions of greenhouse gas nitrous oxide (N2O) more complicated. This study investigated the N2O emissions from a batch-fed aerobic granular sludge system during nitrification of low-strength synthetic ammonium wastewater. The N2O emission was 2.72 ± 0.52% of the oxidized ammonium during the whole anoxic-oxic sequencing batch reactor (SBR) cycle. Under nitrification batch test with sole ammonium substrate (50 mg N/L), N2O emission factor was 1.82% (N2ON/NH4+-Nox) and ammonia-oxidizing bacteria (AOB) was the responsible microorganism. The presence of high ammonium concentration (or high ammonium oxidation rate (AOR)) and accumulation of nitrite would lead to significant N2O emissions. AOB denitrification pathway was speculated to contribute more to the N2O emissions under nitrification conditions. While under simultaneous nitrification and denitrification condition with carbon source of 500 mg COD/L, the N2O emission factor increased to 2.76%. Both AOB and heterotrophic denitrifiers were responsible for N2O emission and heterotrophic denitrification enhances N2O emission. Step feeding of organic carbon source declined N2O emission factor to 1.60%, which underlined the role of storage substance consumption in N2O generation during denitrification.
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
authors.forename: Mingming
authors.initials: M
authors.lastname: Gao
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
authors.forename: Sen
authors.initials: S
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan 250100, China.
authors.forename: Mingyu
authors.initials: M
authors.lastname: Wang
authors.affiliation: Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100, China. Electronic address: xinhuawang@sdu.edu.cn.
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Wang
mesh_terms: D000332:Aerobiosis; D064751:Ammonium Compounds / Q000737:chemistry*; D019149:Bioreactors / Q000382:microbiology; D058440:Denitrification; D052836:Heterotrophic Processes; D058465:Nitrification; D009573:Nitrites / Q000378:metabolism; D009609:Nitrous Oxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000737:chemistry*
chemical_list: D064751:Ammonium Compounds; D009573:Nitrites; D009609:Nitrous Oxide; D012722:Sewage; D062065:Wastewater
keywords: Aerobic granular sludge; Low strength ammonium wastewater; Nitrifier denitrification; Nitrous oxide; Simultaneous nitrification and denitrification