Date of Award
Doctor of Philosophy (PhD)
Environmental Engineering and Science
Molz , Fred
Snider , Eric
Rodgers , John
Pilot-scale wetland treatment systems were designed and constructed to evaluate renovation of simulated oilfield produced water contaminated with ammonia (20 mg/L ammonia-N). A process-based pilot-scale constructed wetland was designed to meet specific biogeochemical conditions for conversion of ammonia to nitrogen gas through microbial nitrification and denitrification. The process-based constructed wetland treated the simulated produced water to meet stringent discharge requirements (less than 1.2 mg/L ammonia-N). Clinoptilolite, a zeolite mineral, was evaluated for use in constructed wetlands to increase ammonia sorption and nitrification activity. Clinoptilolite increased wetland ammonia sorption capacity and served as a microbial carrier for nitrifying bacteria when ranges of conditions (e.g. hydrosoil redox and equilibrium ammonia concentration) were met. Vertical tracer tests performed on bench-scale constructed wetlands demonstrated that plant transpiration enhances transport of water and dissolved constituents though the hydrosoil, where biogeochemical conditions for treatment reactions including denitrification occur. Evapotranspiration measured using a small, 2 m2 lysimeter was compared with evapotranspiration previously reported for large-stand wetlands (greater than 1 hectare) to compare differences in evapotranspiration water loss expected between pilot-scale and full-scale constructed wetlands. Although water loss by evapotranspiration from the pilot-scale wetland (Kc = 2.54) was greater than reported from large-stand wetlands (Kc = 1.0), performance differences predicted using a one-dimensional analytical model were negligible for treatable constituents (k = 1.2 d-1). This research demonstrates that constructed wetlands offer a solution to treating ammonia in produced water to meet surface discharge criteria and beneficial use guidelines.
Beebe, Donald, "Renovation of Ammonia Contaminated Produced Water Using Constructed Wetlands" (2013). All Dissertations. 1187.