Degradation of Chlorinated Ethenes in Mesocosms Simulating a Constructed Wetland, at WPAFB, Ohio

The main purpose of this research was to study the degradation of chlorinated ethenes in upwardflowing mesocosms, simulating a constructed wetland at Wright Patterson Air Force Base (WPAFB) in Dayton, Ohio. This research was intended to compare biogeochemical processes and PCE degradation occurring in the mesocosms and in the field site. This research also tries to look at the effects of vegetation and season on the degradation efficiency of the mesocosms. Twelve PVC column reactors were built within the greenhouse of Wright State University in September 2005 to simulate the hydraulic conditions of a constructed wetland at WPAFB. The columns were filled with wetland soils. Three kinds of wetland plants, Scirpus atrovirens (green bulrush), Carex comosa (longhaired sedge) and Eleocharis erythropoda (spike rush) were planted in nine of the reactors and three were left unplanted (control). Water samples were collected from the reactors for a period of one year and analyzed in the laboratory using a gas chromatography system (HP 6890 GC) to detect the concentration of chlorinated ethenes and methane. Degradation of PCE along with formation of the daughter products TCE, DCE, VC and Ethene were detected in the reactors. Both anaerobic and aerobic degradation processes were taking place within the reactors. Strong seasonal trends seen in the planted reactors were not so evident in the control reactors