Measurement of Denitrification Rates in a Constructed Wetland Receiving Municipal Solid Waste Landfill Leachate

Constructed wetland systems have the potential of providing a low cost and low maintenance wastewater treatment alternative for nitrogen removal. This paper describes a method developed to investigate denitrification as a nitrogen removal pathway in constructed wetlands. The method allows collection of information on rate limiting factors that can be used to improve the nitrogen treatment capabilities of these systems. A modified acetylene block method was developed to measure denitrification rates in the laboratory. This method was used to measure denitrification rates of soil cores from the effluent of a constructed wetland. Background denitrification rates as well as potential denitrification rates using sodium acetate were measured. The average background and potential denitrification rates were 5.06 ± 1.9 g N/m³/d and 18.0 ± 0.89 g N/m³/d, respectively. Average nitrate nitrogen loading and removal rates from water sampling during 1997 were 11.7 ± 3.1 and 4.01 ± 1.8 g N/m³/d, respectively.