DENITRIFICATION IN A NATURAL WETLAND RECEIVING SECONDARY TREATED EFFLUENT

The potential of a natural wetland as a site for nitrogen removal from secondary treated effluent was examined by investigating the distribution of denitrification rates and activity in soils and decaying plant material. The effluent inflow increased the concentrations of inorganic nitrogen in the soil, and encouraged higher rates of dentrification. Denitrification rates measured by an acetylene blockage technique were highest in soil samples from downstream of the effluent inflow. Denitrification rates in the natural wetland are increased by the addition of secondary treated effluent, and make a year-round contribution to the removal of nitrogen from the wastewater. Additional aspects of the study are discussed.