Using a Hydroponic System with Tall Fescue to Remove Nitrogen and Phosphorus from Renovated Turkey Processing Wastewater

Abstract

Abstract. Rising nitrogen and phosphorus related nutrient pollution in different aquifers, as indicated by the deterioration of water quality, triggered this study. The aim of this study was to use commercially valuable ornamental plants, such as tall fescue, for wastewater treatment without decreasing the overall treatment efficiencies of a laboratory-scale hydroponic (soilless) system. Renovated turkey processing wastewater, from a sand bioreactor treatment system at a turkey processing plant, was used in this experiment. Nitrate and phosphate were measured in influent and effluent of the hydroponic system to evaluate the nutrient removal efficiency. Tall fescue was cultured on media consisting of perforated plastic plates and one layer of burlap. Water samples were tested at 12 h intervals under 2-day hydraulic retention times. Average removals of 53% nitrate and 68% soluble reactive phosphate were achieved at 48 h under 2-day hydraulic retention time. The 2-day retention time was optimal for nutrient removal at 22 to 28 days of growth. The plant nutrient content was also determined. The tall fescue hydroponic system, including possible microbial participation, accounted on average for 14% nitrate-N and 42% P removal. Improvement in the efficiencies could come from a better understanding of the biological mechanisms and controls of nutrient removal.