title: Enhancement of nitrate removal at the sediment-water interface by carbon addition plus vertical mixing.
abstract: Wetlands and ponds are frequently used to remove nitrate from effluents or runoffs. However, the efficiency of this approach is limited. Based on the assumption that introducing vertical mixing to water column plus carbon addition would benefit the diffusion across the sediment-water interface, we conducted simulation experiments to identify a method for enhancing nitrate removal. The results suggested that the sediment-water interface has a great potential for nitrate removal, and the potential can be activated after several days of acclimation. Adding additional carbon plus mixing significantly increases the nitrate removal capacity, and the removal of total nitrogen (TN) and nitrate-nitrogen (NO3(-)-N) is well fitted to a first-order reaction model. Adding Hydrilla verticillata debris as a carbon source increased nitrate removal, whereas adding Eichhornia crassipe decreased it. Adding ethanol plus mixing greatly improved the removal performance, with the removal rate of NO3(-)-N and TN reaching 15.0-16.5 g m(-2) d(-1). The feasibility of this enhancement method was further confirmed with a wetland microcosm, and the NO3(-)-N removal rate maintained at 10.0-12.0 g m(-2) d(-1) at a hydraulic loading rate of 0.5 m d(-1).
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Dong Chuan Road 800, Shanghai 200240, PR China; Ecosystems Center, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543, USA. Electronic address: cxcsnow@163.com.
authors.forename: Xuechu
authors.initials: X
authors.lastname: Chen
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Dong Chuan Road 800, Shanghai 200240, PR China.
authors.forename: Shengbing
authors.initials: S
authors.lastname: He
authors.affiliation: Shanghai East Sea Marine Engineering Survey & Design Institute, Shanghai 200137, PR China.
authors.forename: Yueping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Dong Chuan Road 800, Shanghai 200240, PR China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Huang
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Dong Chuan Road 800, Shanghai 200240, PR China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Huang
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Dong Chuan Road 800, Shanghai 200240, PR China.
authors.forename: Danyue
authors.initials: D
authors.lastname: Chen
authors.affiliation: Shanghai East Sea Marine Engineering Survey & Design Institute, Shanghai 200137, PR China.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Huang
authors.affiliation: Ecosystems Center, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543, USA.
authors.forename: Jianwu
authors.initials: J
authors.lastname: Tang
mesh_terms: D001673:Biodegradation, Environmental; D002244:Carbon / Q000737:chemistry*; D005618:Fresh Water / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D009566:Nitrates / Q000032:analysis / Q000737:chemistry*; D009584:Nitrogen; D009589:Nitrogen Oxides; D014867:Water; D018508:Water Purification / Q000379:methods; D053833:Wetlands
chemical_list: D009566:Nitrates; D009589:Nitrogen Oxides; D014867:Water; D002244:Carbon; D009584:Nitrogen
keywords: Carbon addition; Nitrate removal; Sediment–water interface; Vertical mixing