Click on “Download PDF” for the PDF version or on the title for the HTML version.

If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.

A pilot-scale duckweed pond was installed and integrated into the existing swine wastewater management system of a swine farm in Zebulon, North Carolina to investigate its effectiveness in removing nutrients from anaerobically treated swine wastewater. The nutrient-rich wastewater was added intermittently into the duckweed pond to maintain an ammonium (NH4-N) concentration of about 20 mg L-1, and the duckweed was harvested regularly to ultimately remove nutrients from the water body. The results show that duckweed (Spirodela polyrrhiza) grew rapidly on swine wastewater under field conditions, with a dry biomass yield of 10.7 g m-2 d-1 in August and September. Over the 16-week experimental period, NH4-N, the major nutrient concern in swine wastewater, was removed at 1.12 g m-2 d-1. The fast duckweed growth and an average duckweed protein content of 26.3% enabled a protein yield of 2.11 g m-2 d-1 throughout the experiment.