Seasonal Nutrient Dynamics in a Small-Scale Constructed Wetland Treating Primary Effluent with Applications of Effluent Reuse in Biomass Production

Constructed wetlands have been investigated for use in the treatment of municipal wastewater. Species of nitrogen and phosphorus are the nutrients of focus and biochemical oxygen demand (BOD), total suspended solids (TSS) and fecal coliform are the pollutants. Prior work has focused on design concepts, plant effects on nutrient and pollutant treatment, and annualized treatment performance characteristics. This work builds upon published design concepts and wetland plant community and its function and investigates seasonal treatment performance and the kinetics of treatment performance for certain nutrients and pollutants during each season. Previous engineering based work has broadly suggested that first order kinetics govern the treatment chemistry of constructed wetlands. This work further investigates wetland chemistry by evaluating zero, first and second order kinetics for each season for certain nutrients and pollutants and compares regression analysis results between the orders. The results suggest that second order kinetics more closely describe the treatment kinetics realized. In addition, this work investigates an alternate function for constructed wetlands as a nutrient and pollutant buffer with the wetland effluent providing irrigation water for industrial crops. The industrial crops are then proposed to be utilized for energy production. Furthermore, a simple design model attempts to provide a rapid assessment of feasibility of constructed wetlands as a nutrient and pollutant buffer. The design model may be used by a municipality to quickly determine the feasibility of installing a wetland irrigation system as part of their overall wastewater treatment system. Finally, a simple mathematical correlation between a municipality\u27s diesel fuel use and the projected size of a constructed wetland is presented