title: Applying a resting operation to alleviate bioclogging in vertical flow constructed wetlands: an experimental lab evaluation.
abstract: The aim of this study is to evaluate the effects of and analyze the reasons for applying a resting operation to alleviate bioclogging in vertical flow constructed wetlands (VFCWs). In parallel, three groups of laboratory-scale VFCWs were continuously fed with prepared wastewater (BOD = 600 mg/L) at a relatively high hydraulic loading rate of 0.5 m(3)/m(2)·d until clogging. Parameters related to the clogging of the wetland substrate before and after resting were examined and measured. The results showed that the resting operation could effectively alleviate bioclogging because the hydraulic conductivity and effective porosity were improved after 3, 7 and 10 days of resting. In the upper 0-10 cm layer, the hydraulic conductivity increased 2.0, 2.6 and 3.5 times, respectively, for the three resting periods. The reduction of the extracellular polymeric substance (EPS), biofilm decay and the consequential change in the biofilm structure are the main reasons that the resting operation relieved clogging. In addition, the observed and theoretical resting times (approximately 7 days) agreed well. The results provide a theoretical basis and technical support for solving clogging problems.
authors.affiliation: College of Water Conservancy and Hydroelectric Power, Hohai University, No. 1 Xikang Road, Nanjing 210098, PR China; State Key Laboratory of Hydrology-Water Resource and Hydraulic Engineering, Hohai University, No. 1 Xikang Road, Nanjing 210098, PR China. Electronic address: Huaguofen2005@126.com.
authors.forename: Guofen
authors.initials: G
authors.lastname: Hua
authors.affiliation: College of Water Conservancy and Hydroelectric Power, Hohai University, No. 1 Xikang Road, Nanjing 210098, PR China.
authors.forename: Yitao
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Hydrology-Water Resource and Hydraulic Engineering, Hohai University, No. 1 Xikang Road, Nanjing 210098, PR China; College of Environment, Hohai University, No. 1 Xikang Road, Nanjing 210098, PR China.
authors.forename: Zhongwei
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: College of Water Conservancy and Hydroelectric Power, Hohai University, No. 1 Xikang Road, Nanjing 210098, PR China.
authors.forename: Kaibo
authors.initials: K
authors.lastname: Cheng
authors.affiliation: College of Water Conservancy and Hydroelectric Power, Hohai University, No. 1 Xikang Road, Nanjing 210098, PR China.
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
mesh_terms: D001673:Biodegradation, Environmental; D018441:Biofilms; D018533:Biomass; D008962:Models, Theoretical; D011108:Polymers / Q000737:chemistry; D016062:Porosity; D012498:Sanitary Engineering / Q000379:methods*; D062065:Wastewater / Q000737:chemistry; D014871:Water Microbiology; D053833:Wetlands
chemical_list: D011108:Polymers; D062065:Wastewater
keywords: Biofilm; Clogging; Constructed wetlands; Resting operation