Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2002
Publication Date: 5/1/2003
Citation: Adler, P.R., Sibrell, P.L. 2003. Sequestration of phosphorus by acid mine drainage floc. J Evniron, Qual, 32:1122-1129.
Interpretive Summary: Discharge of phosphorus to surface water is the most critical issue limiting the continued expansion of the coldwater aquaculture industry. Application of amendments containing aluminum, iron, and calcium can reduce the loss of phosphorus. When acid mine drainage is neutralized, a floc containing aluminum, iron, and calcium materials is formed. It is a waste byproduct of cleaning the water and in this study, was tested for its ability to remove phosphorus from aquaculture water. We found that it did remove significant amounts of phosphorus from water. Handling and disposal of these waste byproducts can account for half the cost of cleaning the acid mine drainage water. Using the acid mine drainage byproducts to remove phosphorus reduces the costs of cleaning water from aquaculture facilities and acid mine drainage.
Technical Abstract: Loss of P to the water environment is a critical issue facing agriculture. Acid mine drainage (AMD) neutralization flocs were tested as a possible low cost amendment to reduce the loss of soluble P. These flocs are a readily available waste product in many regions of the US. Phosphorus removal was determined for flocs produced by neutralization of natural and synthetic solutions of AMD with different compounds including calcium carbonate, calcium hydroxide, ammonium hydroxide and sodium hydroxide. Flocs prepared from AMD using differing neutralization compounds were similar in composition and adsorbed 15 to 30 g P/kg dry floc. Local soils were tested for comparison and adsorbed about 0.1 g P/kg, about two orders of magnitude less. Flocs made by neutralization of Fe and Al solutions were equally effective, and adsorbed 10 to 30 g P/kg floc. The AMD-derived flocs were mixed with a high-P soil at 5-80 g floc/kg soil, followed by water and acid d(Mehlich-1) extractions. All flocs performed similarly. Water extractable P decreased from 120 mg/kg to about 25 mg/kg at a 20 g/kg amendment rate, whereas plant available P only decreased by about 30%. Under anaerobic conditions, all AMD flocs reduced soluble P by greater than 95% at a rate of 0.2 g floc/g manure. When calcium hydroxide was applied to lime stabilize the manure, P removal was similar to AMD flocs. These findings indicate that AMD flocs could be an effective agent for prevention of P movement to the water environment, while at the same time decreasing the costs associated with treatment of AMD.