title: Sanitation in constructed wetlands: A review on the removal of human pathogens and fecal indicators.
abstract: Removal of human pathogens from wastewater is a critical factor with linkage to human health. Constructed Wetlands (CWs) are environmental friendly ecosystems that are applicable not only for chemical pollution control, but also for the reduction of pathogens from wastewater. Yet the knowledge on the fate and removal of such indicator bacteria in CWs is still not sufficient due to the complexity of removal mechanisms and influencing factors. This review serves to provide a better understanding of this state-of-the-art technology, which is necessary for further investigations and design development. The fecal indicator bacteria in CWs mainly come from three sources, namely, influent wastewaters, regrowth within the CWs, and animal activities. The properties of microbial contamination vary depending on the different sources. The removal of pathogens is a complex process that is influenced by operational parameters such as hydraulic regime and retention time, vegetation, seasonal fluctuation, and water composition. The most frequent and well-validated removal mechanisms include natural die-off due to starvation or predation, sedimentation and filtration, and adsorption. The concentration of the main fecal indicator bacteria in the effluent was found to be exponentially related to the loading rate. Generally, horizontal subsurface flow CWs have better reduction capacity than free water surface flow CWs, and hybrid wetland systems were found to be the most efficient due to a longer retention time. Further improvement of fecal indicator bacteria removal in CWs is needed, however, levels in CW effluents are still higher than most of the regulation standards for reuse.
authors.affiliation: College of Engineering, China Agricultural University, Key Laboratory for Clean Renewable Energy Utilization Technology, Ministry of Agriculture, Beijing 100083, PR China. Electronic address: wushubiao@gmail.com.
authors.forename: Shubiao
authors.initials: S
authors.lastname: Wu
authors.affiliation: Department of Bioscience, Aarhus University, 8000C Aarhus, Denmark.
authors.forename: Pedro N
authors.initials: PN
authors.lastname: Carvalho
authors.affiliation: Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Germany.
authors.forename: Jochen A
authors.initials: JA
authors.lastname: Müller
authors.affiliation: Department of Chemistry, Velammal Engineering College, Chennai, India.
authors.forename: Valsa Remony
authors.initials: VR
authors.lastname: Manoj
authors.affiliation: College of Engineering, China Agricultural University, Key Laboratory for Clean Renewable Energy Utilization Technology, Ministry of Agriculture, Beijing 100083, PR China.
authors.forename: Renjie
authors.initials: R
authors.lastname: Dong
mesh_terms: D001419:Bacteria; D001673:Biodegradation, Environmental; D017753:Ecosystem; D005243:Feces; D005374:Filtration; D006801:Humans; D012499:Sanitation; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000382:microbiology*; D014871:Water Microbiology; D014873:Water Pollutants / Q000032:analysis*; D053833:Wetlands
chemical_list: D062065:Wastewater; D014873:Water Pollutants
keywords: Constructed wetlands; Fecal indicators; Mechanisms removal of bacteria; Sanitation; Wastewater treatment performance; Waterborne pathogens