Date of Award

1992

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Oceanography and Coastal Sciences

First Advisor

John W. Day, Jr

Abstract

Two major environmental problems currently affecting Louisiana are a high rate of coastal wetland loss and high levels of surface water pollution. The application of secondarily treated wastewater to wetlands is proposed as a means of dealing with these problems. The benefits of wetland wastewater treatment include improved surface water quality, increased accretion rates to balance subsidence, improved plant productivity, and decreased capital outlays for conventional engineering treatment systems. Wetland treatment systems can be designed and operated to restore deteriorating wetlands to previous levels of productivity. Hydrologically altered wetlands in the Louisiana coastal zone have been selected as appropriate for receiving municipal and some types of industrial effluent. While the U.S. Environmental Protection Agency has determined that wetland wastewater treatment is effective in treating municipal effluent, it has discouraged the use of natural wetlands for this purpose. As a result, hydrologically altered wetlands in the Louisiana coastal zone are being neglected and ultimately lost, while scarce funds are being applied to the construction of artificial wetlands to treat municipal effluent. Effluent discharge to existing wetlands can be incorporated into a comprehensive management plan designed to increase sediment and nutrient input into subsiding wetlands in the Louisiana coastal zone. Secondarily treated effluent discharged from industrial and municipal facilities in the Louisiana coastal zone were reviewed for their suitability for wetland wastewater treatment. Selection criteria for wetland treatment systems were developed for both dischargers and receiving wetlands. Analysis of field data for two existing wetland treatment projects shows favorable results. Designs for two potential case studies based on established selection criteria for wetland wastewater treatment systems are presented. An economic analysis of the four case studies indicates a high potential for financial savings when wetlands replace conventional engineering methods for tertiary treatment.

Pages

245

Share

COinS