Phosphorus removal in agricultural wastewater by a recently constructed wetland

Abstract

Constructed wetlands are gaining increased attention for treatment of various types of agricultural-source pollution. A four-cell surface-flow wetland was constructed during the 1996 spring season and was used immediately the same summer and fall. While the general purpose of the project is to monitor the efficiency of the system under various operating conditions, the specific interest of this first year of operation was to study its efficiency in reducing phosphorus during the first weeks of use. With inflow concentrations around 20 mg/L, the removal of phosphorus was limited to 50% for ortho-P and 63% for total P during the first summer of use. Important horizontal and vertical gradients in P concentrations were also noted, and the initial choice of a convenient soil was questioned.Key words: constructed wetland, phosphorus.