title: Nitrogen removal from Lake Caohai, a typical ultra-eutrophic lake in China with large scale confined growth of Eichhornia crassipes.
abstract: An ecological engineering project, with large-scale utilization of Eichhornia crassipes (coverage area ∼4.3km(2)) for pollution control in an open ultra-eutrophic lake, Lake Caohai, was first implemented in 2011. In this study, the efficiency of N removal using E. crassipes in the lake was evaluated. After E. crassipes was planted in May, the concentrations of TN and NH4(+) in Waicaohai, the main part of Lake Caohai, were significantly decreased within a month, and then, remained stable from June to November, 2011, although the lake had received waste water continuously from river inlets. The average concentrations of TN, NH4(+)-N and NO3(-)-N in water of Xi Yuan Channel (outlet) were reduced to 3.3, 0.02 and 0.8mgL(-1) from 13.8, 4.7 and 5.8mgL(-1) in river inlets, respectively. The DO levels in 2011 were not decreased, but concentrations of TN and NH4(+) were significantly reduced when compared with the historical data from 2007 in the lake. Assimilation by E. crassipes was the main pathway to remove N in Lake Caohai, accounted for 52% of the total N influent (936t), or 64% of the removed N (761t). These results indicated that large scale utilization of E. crassipes for removal of N in the eutrophic lake is practicable.
authors.affiliation: Institute of Agricultural Resource and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China. zwang@whigg.ac.cn
authors.forename: Zhi
authors.initials: Z
authors.lastname: Wang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yingying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Junqian
authors.initials: J
authors.lastname: Zhang
authors.forename: Shaohua
authors.initials: S
authors.lastname: Yan
authors.forename: Junyao
authors.initials: J
authors.lastname: Guo
mesh_terms: D018533:Biomass; D002681:China; D031806:Eichhornia / Q000254:growth & development* / Q000378:metabolism; D005068:Eutrophication; D056127:Hydrobiology; D060106:Lakes; D009584:Nitrogen / Q000302:isolation & purification / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D000644:Quaternary Ammonium Compounds; D014874:Water Pollutants, Chemical; D009584:Nitrogen