New constructed wetlands can control gaseous emissions: study

BEIJING, Oct. 26 (Xinhua) -- Chinese researchers have discovered that a new type of constructed wetland can not only enhance water purification efficiency but also control gaseous emissions.

The researchers from the Northeast Institute of Geography and Agroecology under the Chinese Academy of Sciences have combined microbial fuel cells (MFCs) with constructed wetlands (CWs) based on the principles of electrochemistry and microbiology.

Thereafter, they quantitatively compared the pollutant removal efficiency and the emission of multiple gases between MFC-CWs and the traditional batch-fed wetland systems (BF CWs), according to a paper published in the journal Water Research.

The study demonstrated that compared with the BF CWs, the MFC-CWs can not only generate electric energy and improve sewage purification efficiency, but also reduce multiple gas emissions, with its CH4, N2O and NH3 fluxes being reduced by 34 percent, 28 percent and 52 percent respectively.

The study also indicated that the reduced N2O fluxes in MFC-CWs were driven by the reduced transcription of the nosZ gene and enhanced the ratio of nosZ/(nirS + nirK). The reduced CH4 fluxes were related to pomA and mcrA.

This study interprets the working mechanism and function of MFC-CWs from a new perspective and provides a new strategy for simultaneously removing pollutants and abating multiple gas emissions.