Differential Nitrous oxide emission and microbiota succession in constructed wetlands induced by nitrogen forms.

Nitrous oxide (NO) emission during the sewage treatment process is a serious environmental issue that requires attention. However, the NO emission in constructed wetlands (CWs) as affected by different nitrogen forms in influents remain largely unknown. This study investigated the NO emission profiles driven by microorganisms in CWs when exposed to two typical nitrogen sources (NH-N or NO-N) along with different carbon source supply (COD/N ratios: 3, 6, and 9).

Microbiota and genetic potential for reducing nitrous oxide emissions by biochar in constructed wetlands.

The denitrification process in constructed wetlands (CWs) is responsible for most of the nitrous oxide (NO) emissions, which is an undesired impact on the ecology of sewage treatment systems. This study compared three types of CWs filled with gravel (CW-B), gravel mixed with natural pyrite (CW-BF), or biochar (CW-BC) to investigate their impact on microbiota and genetic potential for NO generation during denitrification under varying chemical oxygen demand (COD) to nitrate (NO-N) ratios. The results showed that natural pyrite and biochar were superior in enhancing COD (90.

Reducing the inhibitive effect of fluorine and heavy metals on nitrate reduction by hydroxyapatite substrate in constructed wetlands.

Bio-toxic inorganic pollutants, e.g., fluorine (F) and heavy metals (HMs), in wastewaters are the potential threats to nitrate (NO-N) reduction by microorganisms in constructed wetlands (CWs).

Interactive effects of aquatic nitrogen and plant biomass on nitrous oxide emission from constructed wetlands.

Understanding of mechanisms in nitrous oxide (NO) emission from constructed wetland (CW) is particularly important for the establishment of related strategies to reduce greenhouse gas (GHG) production during its wastewater treatment. However, plant biomass accumulation, microbial communities and nitrogen transformation genes distribution and their effects on NO emission from CW as affected by different nitrogen forms in aquatic environment have not been reported. This study investigated the interactive effects of aquatic nitrogen and plant biomass on NO emission from subsurface CW with NH-N (CW-A) or NO-N (CW-B) wastewater.

Effect of spray aeration on organics and nitrogen removal in vertical subsurface flow constructed wetland.

The objective of present study was to assess the simultaneous removal of organics and nitrogen by four lab-scale vertical subsurface flow constructed wetlands (V-SFCWs). The emergent plants employed were Canna indica. Five-month experiments showed that the planted and aerated system largely reduced the COD by 95%, NH4 by 88% and total inorganic nitrogen (TIN) by 83%.