Scrape-and-Replace Method to Minimize Ammonium Transport from Animal Waste Lagoons

Abstract

Contamination of ground water due to leaking animal waste lagoons is a subject of debate in many agriculture-based states in North America. Nitrification of ammonium in the subsurface occurs under unsaturated and aerobic conditions. An excessive amount of nitrogen (in nitrate form) in drinking water supplies and in streams has significant effect on the environment. The results from this study suggest a method of effective lagoon management to minimize ammonium transport from the lagoons. Ammonium transport was simulated on a field scale liner-subsurface profile to estimate the ammonium concentrations in the soil profile for various operation scenarios. Ammonium transport properties—retardation coefficient and decay coefficient—were chosen from previously published literature on the same soil. Results indicate that the ammonium concentrations were significantly reduced in the soil profile when the scrape-and-replace technique was used. The results also suggest that higher scraping depth and frequent replacement of the top of the liner significantly reduced the ammonium concentrations leaching out of the liner.