ARS | Publication request: Reducing phosphorus in swine effluent with aluminum chloride treatment during lagoon cleanout

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 10, 2010
Publication Date: December 1, 2010
Citation: Delaune, P., Moore Jr., P.A. 2010. Reducing phosphorus in swine effluent with aluminum chloride treatment during lagoon cleanout. Applied Engineering in Agriculture. 26:867-871.

Interpretive Summary: Phosphorus runoff from pastures fertilized with animal manure can degrade water quality. The goal of this study was to determine if aluminum chloride applications to a swine lagoon during cleanout could reduce soluble phosphorus levels in the manure and in runoff from land fertilized with the manure. There were four treatments:(1) normal manure, (2) manure treated with aluminum chloride while still in the lagoon, (3) manure treated with aluminum chloride after it had been removed from the lagoon, and (4) manure treated with aluminum chloride and lime after it had been removed from the lagoon. Rainfall simulations were conducted 1, 8, 15, 17 and 24 days after the manure had been applied. All aluminum chloride treatments reduced soluble phosphorus concentrations and loads in runoff, with the best treatment (aluminum chloride plus lime) reducing soluble phosphorus concentrations by 69%. This study indicates that aluminum chloride applications to swine lagoons can result in significantly less phosphorus runoff.

Technical Abstract: Phosphorus (P) runoff from agricultural lands fertilized with swine manure can be a significant environmental issue. The objective of this study was to evaluate the effect of aluminum chloride (AlCl3) applications to a swine lagoon during total clean out on P concentrations in manure and runoff water. There were four treatments: 1) untreated manure; 2) manure treated with AlCl3 in-situ; 3) manure treated with AlCl3 post collection; and 4) manure treated with AlCl3 plus lime post collection. Manure applications were equivalent to 112 kg P ha-1. Rainfall simulators were used to provide a 5-cm hr-1 storm event 1, 8, 15, 17, and 24 days after application. All AlCl3 amendments significantly reduced manure soluble reactive P (SRP) concentrations. The AlCl3/Lime treatment was the most effective, reducing manure SRP concentrations by 69% compared to the untreated manure. In runoff water, SRP loads were significantly higher from plots fertilized with the untreated manure. Cumulative SRP loads were 30% lower from plots fertilized with manure treated with AlCl3 in-situ than the untreated manure. Cumulative P losses increased as SRP application rates increased. Treatment of manure with AlCl3 in-situ can significantly decrease manure SRP concentrations and subsequently reduce P loss from fields receiving manure applications.