Phosphorus Leaching in Sandy Outwash Soils following Potato-Processing Wastewater Application.

This article cites a study on phosphorus (P) leaching in sandy outwash soils following potato-processing wastewater application. Land application is commonly used by food processing facilities as a disposal method for the large quantities of wastewater generated during processing of food products. The wastewater typically contains large amounts of nutrients of environmental significance, particularly nitrogen and phosphorus. Irrigation with large volumes of such wastewater presents potential for ground and surface water contamination from P and other pollutants, if not properly managed. If applied in accordance with crop water and P use, land disposal works well during the growing season. Results indicate no P leaching in low P soils, but leaching in high P soils, thus suggesting that most of the P leached at the high P sites was mainly due to desorption and dissolution of weakly adsorbed P from prior P applications. This was consistent with P transport simulations using the convective-dispersive equation. It is concluded that P concentration in land-applied wastewater should be regulated based on soil test-P level plus wastewater P loading.