Date of Graduation

Spring 5-22-2015

Document Type

Project

Degree Name

Master of Science in Environmental Management (MSEM)

College/School

College of Arts and Sciences

Department/Program

Environmental Management

First Advisor

Kathleen Jennings

Abstract

Constructed wetlands for wastewater treatment (CWWT) are engineered wetland systems created to emulate the processes that occur in natural wetlands. This research focused on looking at the effectiveness of selected contaminant removal based on pilot-scale and full-scale case studies conducted in Mediterranean climate regions around the world for potential application to Mediterranean climate regions in California. The case studies consisted of three basic design types: vertical subsurface flow (VSSF), horizontal subsurface flow (HSSF), and free water surface (FWS) flow systems. All three systems showed high removal rates of total suspended solids (TSS) and organic matter: biological oxygen demand (BOD) and chemical oxygen demand (COD). Removal rates for pathogenic microorganisms and nutrients such as total Kjeldahl nitrogen and total phosphorous were variable among the case studies. Overall removal effectiveness was affected by various factors such as the presence of macrophytes, temperature, hydraulic loading rates (HLRs) and hydraulic retention times (HRTs). These factors may have an impact on microbial habitat for attachment, microbial activities, and filtering capabilities of the systems. As water scarcity and loss of microhabitat issues are becoming more imminent in California, free water surface (FWS) flow constructed wetlands show potential as a low maintenance “natural” treatment option that also provides ancillary ecological benefits, including wildlife habitat.

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