Submitted to: Agricultural and Environmental Biotechnology Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/15/2003
Publication Date: 11/22/2003
Citation: Moore Jr, P.A. 2003. Reducing ammonia emissions and phosphorus runoff from animal manure with aluminum compounds. In: Proceedings of Agricultural and Environmental Biotechnology Congress. 4th International Symposium of Life Science Research Institute's Agriculture, Biotechnology and Environment, November 18-22, 2003, Daegu University, Daegu, Korea. p. 1-12. Interpretive Summary: This paper is a review of research that has been conducted on the benefits of adding aluminum sulfate (alum) to poultry manure and aluminum chloride to swine manure. The two biggest environmental problems with animal manures are ammonia evaporation into the atmosphere and phosphorus runoff into lakes and rivers. When ammonia evaporates from manure it not only causes poor animal production, due to high levels of ammonia in animal rearing facilities; it causes acid rain and other atmospheric pollution. Phosphorus runoff causes excessive algal blooms. Research has shown that additions of aluminum sulfate (alum) to poultry litter with reduce phosphorus runoff by 75% and reduce ammonia emissions by 70%. Reductions in ammonia in the house when alum is used caused improved poultry performance, making this treatment very cost effective. Approximately 600 million chickens are grow with alum each year. Liquid manures, like swine manure, need to be treated with a different compound since the sulfate in aluminum sulfate can cause the rotten egg odor under conditions with no oxygen, such as those present in liquid manures. The best compound for these liquid manures for reducing phosphorus runoff and inhibiting ammonia loss is aluminum chloride.
Technical Abstract: This is a review paper on research that has been conducted on the effects of adding aluminum sulfate to poultry manure and aluminum chloride to swine manure. Applications of aluminum sulfate (Al2(SO4)3.14H2O), commonly referred to as alum, to poultry litter have been shown to reduce ammonia emissions by 70% in commercial broiler facilities. Reductions in ammonia emissions associated with alum resulted in improved weight gains in poultry, better feed conversion, lower mortality and lower energy costs (due to reduced ventilation requirements in cooler months). Phosphorus runoff from small watersheds was 75% lower with alum, compared to normal manure. As a direct result of this research over 600 million chickens are currently grown in the U.S. with alum. Although aluminum sulfate has been successfully in used to treat dry manure, such as poultry litter, it is not suitable for liquid manure, such as liquid swine manure. Under anaerobic conditions, such as that in liquid manures, sulfate is reduced to hydrogen sulfide, causing odor problems. Hence, the best amendment to reduce ammonia emissions and phosphorus runoff from swine manure is aluminum chloride. Aluminum chloride additions to swine manure inhibit ammonia emissions in two ways. First, the reduction in pH shifts the ammonia/ammonium equilibria towards ammonium, which is not subject to volatilization. Secondly, the addition of aluminum chloride to liquid manure results in a thick layer of foam, which acts as a physical barrier to inhibit ammonia loss. The aluminum from aluminum chloride binds to the phosphorus, making an insoluble metal phosphate mineral which reduces P runoff. When swine diets are modified using phytase enzymes to reduce dicalcium phosphate levels, the combination of lower dietary P and P precipitation with aluminum chloride results in very low levels of P in runoff water.