title: An innovative wood-chip-framework substrate used as slow-release carbon source to treat high-strength nitrogen wastewater.
abstract: Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems. However, nitrogen removal efficiency is usually limited due to the low carbon/nitrogen (C/N) ratio. A common solution is to add external carbon sources, but amount of liquid is difficult to determine. Therefore, a combined wood-chip-framework substrate (with wood, slag and gravel) as a slow-release carbon source was constructed in baffled subsurface-flow constructed wetlands to overcome the problem. Results show that the removal rate of ammonia nitrogen (NH4+-N), total nitrogen (TN) and chemical oxygen demand (COD) could reach 37.5%-85%, 57.4%-86%, 32.4%-78%, respectively, indicating the combined substrate could diffuse sufficient oxygen for the nitrification process (slag and gravel zone) and provide carbon source for denitrification process (wood-chip zone). The nitrification and denitrification were determined according to the location of slag/gravel and wood-chip, respectively. Nitrogen removal was efficient at the steady phase before a shock loading using slag-wood-gravel combined substrate because of nitrification-denitrification process, while nitrogen removal was efficient under a shock loading with wood-slag-gravel combined substrate because of ANAMMOX process. This study provides a new idea for wetland treatment of high-strength nitrogen wastewater.
authors.affiliation: Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China. Electronic address: lihuai@iga.ac.cn.
authors.forename: Huai
authors.initials: H
authors.lastname: Li
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China.
authors.forename: Zifang
authors.initials: Z
authors.lastname: Chi
authors.affiliation: Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
authors.forename: Baixing
authors.initials: B
authors.lastname: Yan
authors.affiliation: Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
authors.forename: Long
authors.initials: L
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: envhit@aliyun.com.
authors.forename: Jianzheng
authors.initials: J
authors.lastname: Li
mesh_terms: D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D009584:Nitrogen / Q000032:analysis / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D014934:Wood / Q000737:chemistry
chemical_list: D009584:Nitrogen; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Baffled constructed wetland; Combined substrate; Nitrogen; Removal; Wood-chip