A case study on applying subsurface flow constructed wetlands (SFCWs) to treat combined sewer overflows (CSOs)

Combined sewer overflows (CSOs) are a major source of water pollution in old cities with combined sewer systems. During the past 30 years, constructed wetlands have gained acceptance as a means to treat wastewater from domestic, agricultural and industrial sources. This dissertation is focused on the research question whether a specific CSO in Syracuse, NY is amenable to remediation by using a subsurface flow constructed wetland. Research in three different disciplines including technical studies which include water quality science, hydrological engineering, and plant science, sociology, and policy analysis has been conducted in this case study in order to answer the research question.;Water quality study results indicate that most parameters in the SSO exhibit a strong fluctuation with time in terms of their concentration. The result also indicates a moderate negative linear correlation between the 24-hour precipitation level and the ratio of sewage in the CSOs. Additionally, through analyzing the storm event CSO water quality data using multivariate statistical methods, the dominant parameters in the CSOs can be determined. In the wetland design part, the calculation of HRT and the prediction of fecal coliform removal rate for the proposed subsurface flow treatment wetland are conducted by using the k-c* model. In the vegetation selection study, the field experiment shows that both Prairie Cordgrass and Sweet Grass could be good candidate species for the proposed constructed wetland. The public perception study framework for the project is established based on four main study components: (1) Public perception, (2) Physical site user survey, (3) Interpretation/communication, (4) Operation and management. In the policy analysis part, the possibility of using constructed treatment wetlands as an optional BMP for CSO pollution abatement in New York State is analyzed through a modified stages model of policy-making cycle which incorporates a public participation plan. This research adds information to the literature body of constructed wetland studies and can be used in developing CSO mitigation programs.;Key Words: Subsurface Flow Treatment Wetland, Combined Sewer Overflow, Hydraulic Resident Time, Vegetation Selection, Policy-making Cycle...