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Impact of external carbon source addition on methane emissions from a vertical subsurface‐flow constructed wetland
Author(s) -
Liu Xiaoling,
Fu Xiaoying,
Pu Aiping,
Zhang Ke,
Luo Hongbing,
Anderson Bruce C.,
Li Mei,
Huang Bo,
Hu Limei,
Fan Liangqian,
Chen Wei,
Chen Jia,
Fu Shuzhi
Publication year - 2019
Publication title -
greenhouse gases: science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.45
H-Index - 32
ISSN - 2152-3878
DOI - 10.1002/ghg.1847
Subject(s) - methanogenesis , methane , urea , total organic carbon , constructed wetland , carbon fibers , chemistry , environmental chemistry , greenhouse gas , carbon dioxide , environmental science , environmental engineering , ecology , materials science , wastewater , organic chemistry , composite number , composite material , biology
In this study, different concentrations of urea (0, 12.1, 30, 45, 61 and 80 mmol·L −1 ) were added separately, as external carbon sources, to a two‐stage vertical subsurface‐flow constructed wetland (VSSF CW) where Cyperus alternifolius L. was planted, with the aim of understanding methane (CH 4 ) emissions driven by urea. Results indicate that the average CH 4 emissions from a two‐stage VSSF CW were 6.88, 7.11, 6.22, 7.45, 5.06 and 2.80 mol·m −2 ·day −1 , corresponding to urea concentrations of 0, 12.1, 30, 45, 61 and 80 mmol·L −1 added in the VSSF CW, respectively. Urea as a carbon source had an average of 31.57% of influent total organic carbon (TOC). It was transformed into CH 4 ‐C, of which CH 4 ‐C/TOC influent may be be considered as an important component when anthropogenic methanogenesis from treatment wetlands was driven by carbon sources or carbon loading. Methane emissions were at their lowest when the C/N ratio was 5.89, at a urea concentration of 80 mmol·L −1 . Principal component analysis (PCA) indicates that CH 4 correlated positively with temperature and redox conditions (Eh). Methane emissions driven by urea in the two‐stage VSSF CW were found to be in accordance with the second‐rate dynamics kinetic model (kinetic constant = 22.94 mg CH 4 ·h −1 , R 2 = 0.99), which can be considered as a high level of CH 4 emissions. It indicates that external carbon sources can influence CH 4 emissions from two‐stage VSSF CW significantly. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.