Locally Sourced Iron and Aluminum Byproducts Decrease Phosphorus Leached from Broiler House Dust Deposited near Ventilation Fans

Abstract

Freshwater impairment by eutrophication, as a result of excessive phosphorus (P) inputs from runoff in particular, remains a ubiquitous environmental concern. A common issue with systems designed to remove P and nitrogen (N) from runoff is their reduced effectiveness under high-flow conditions. To over-come this, P removal from broiler-house fan dust would be more effective if removal occurred at the nutrient source, where the water volume is limited to direct rainfall. The P removal efficiencies of different thicknesses of locally sourced, iron-rich red mud (RM) generated during the manufacture of steel belts for tires and alum-based drinking water treatment residual (WT) byproducts were investigated. Byproduct thicknesses of 4, 8, and 12 cm were tested using 57-L leaching columns. The columns were filled with the specified byproduct thickness and a 3-mm thickness of poultry house dust was surface applied prior to receiving six, 30-min simulated rainfalls (at 7 cm·hr-1) at 1-day intervals. The 8-cm thickness of both RM and WT outperformed the other thicknesses in terms of sorbing P released from the added broiler house dust, removing 99 and 96% of the added P, respectively, over the six simulated rainfall events. The 12-cm thickness of both RM and WT showed no additional benefit for P removal over the 8-cm thickness. As the 4-cm-thick WT treatment was less effective (89% of added P removed), the 8-cm thickness was the optimal thickness for field testing. Locally sourced materials with large P-sorbing capacities can offer a convenient, relatively inexpensive alternative for P removal from areas around poultry houses impacted by P-containing, exhausted broiler house dust.