Use of Polyacrylamide in Simulated Land Application of Lagoon Effluent: Part I. Runoff and Sediment Loss

Abstract

Agriculture contributes considerably to water quality problems in the U.S. Tillage systems and land application of wastewaters from animal production facilities can increase both sediment and nutrient loadings to surface waters. Sediment transported to surface waters can decrease biodiversity and the usefulness of water for industry, drinking, and recreation. Anionic polyacrylamide (PAM) is a soil amendment that has been shown to reduce soil erosion during rainfall and irrigation. We hypothesized that dissolving PAM in land-applied lagoon effluent would reduce runoff and sediment loss in subsequent rainfalls. Swine wastewater from a third-stage anaerobic lagoon was mixed with high molecular weight PAM at concentrations of 0, 10, and 20 ppm and then surface applied to a silt loam soil packed in erosion boxes. A rainfall simulator was used to study PAM's effectiveness at two slopes (4% and 8%) and two cover levels (0% and 30%). Two consecutive storms with constant and varying rainfall intensity were simulated. PAM treatment reduced runoff from covered soils by up to 66%. On bare soil, the 10 ppm PAM treatment reduced first storm sediment losses by about 60%, while the 20 ppm PAM treatment resulted in about a 40% reduction. Lagoon effluent irrigation was found to produce higher sediment losses than water irrigation, but PAM treatment reduced sediment losses in lagoon-irrigated soils to levels that were comparable to water-only irrigations. These results indicate that application of anionic PAM with wastewater during surface irrigation can be an effective treatment to reduce runoff and erosion during subsequent rainfall events.