Pathways regulating nitrogen removal in constructed ditch wetlands: effects of different inflow ratios and artificial aeration

• Published in: Environmental science and pollution research international Vol. 27; no. 34; pp. 42571 - 42581
• Main Authors: Ma, Yuhui, Zheng, Peiru, Dai, Wanqing, Zheng, Xiangyong, He, Shengbing, Zhao, Min
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2020; Springer Nature B.V
• Subjects: Abundance; Aeration; Aquatic Pollution; Artificial aeration; Artificial wetlands; Atmospheric Protection/Air Quality Control/Air Pollution; Bacteria; Carbon; Carbon sources; Denitrification; Domestic wastewater; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Nitrification; Nitrifying bacteria; Nitrogen; Nitrogen removal; Pollutants; Ratios; Research Article; Rural areas; Waste Water Technology; Wastewater; Water Management; Water Pollution Control; Wetlands; Aeration; Influent flow ratio; Nitrogen removal pathway; Constructed ditch wetlands
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-10224-1

Constructed ditch wetland (CDW) is a combination of idle ditch and constructed wetland, which is typically used in rural areas to remove pollutants from domestic wastewater. However, its low total nitrogen (TN) removal remains a pressing issue. To enhance total nitrogen removal, an approach of supplying water at two locations in the CDW at different influent flow ratios, combined with artificial aeration, was proposed to adjust carbon and oxygen distribution in the system. The highest average TN removal was achieved at low influent concentration (CDW4; influent flow ratio 1:2). The removal of TN in winter and spring were 58.93 and 83.26%, respectively. The distribution of carbon sources in the back zone enhanced denitrification. Of the high influent concentration treatments, CDW2 (2:1) achieved 16.97% more TN removal on average compared with CDW1 (3:0), after extra artificial aeration was applied in the front zone. However, nitrification was a limiting step in the system, which became the primary problem preventing pollutant purification. Moreover, nitrifying bacteria abundance was negatively correlated to the influent flow ratio and autotrophic denitrifying bacterial abundance was positively correlated to the influent flow ratios. Graphical abstract