Nitrogen and phosphorus removal in a constructed wetland receiving agricultural wastewater

Nitrogen (N) and phosphorus (P) resulting from manure run-off and milkhouse washwater can contribute to the impairment of receiving water bodies. Constructed wetlands are engineered systems built to utilize the treatment processes available in natural wetlands in a controlled and predictable manner. A constructed wetland located in Eureka, Nova Scotia was the focus of this study. Adsorption to sediment has been identified as a key wastewater phosphorus (P) removal mechanism in treatment wetlands. Batch incubation experiments were performed to measure the capacity of the wetland soil to remove phosphorus from solution. Nonlinear regression analysis was performed using the Langmuir adsorption model to describe the P adsorption characteristics for each soil under study. Additional experiments were also conducted, to study specific N reactions in vitro. Two in vitro experiments were conducted to examine N mineralization and nitrification. An additional in vitro experiment compared nitrous oxide emissions as a product of denitrification under acetylene blocked and unblocked conditions. A greenhouse wetland model was also constructed to assess the effects of aeration on ammonia-N removal. (Abstract shortened by UMI.)...