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Aeration efficiency of the in-line aeration and neutralization system.
Mine Drainage and Surface Mine Reclamation. Volume I: Mine Water and Mine Waste. Vol. I. Pittsburgh, PA: U.S. Bureau of Mines, 1988 Apr; :403
Acid mine drainage treatment typically involves the removal of soluble metals by neutralization, oxidation, and precipitation. The chemical reactions are frequently limited by the availability of dissolved oxygen. For this reason a study was conducted in the laboratory to establish the aeration efficiency of the In Line Aeration and Neutralization System (ILS). This patented treatment system, developed by the Bureau of Mines, treats mine discharge in a pipeline and involves no moving parts. It consists of two components: a jet pump and a static mixer. Testing procedures were performed in accordance with the American Society of Civil Engineers (A Standard for the Measurement of Oxygen Transfer in Clean Water). The standard requires deoxygenation of a tank of clean water before aeration. The dissolved oxygen concentration in the water is measured over time as it is continuously pumped through the ILS until saturation is achieved. Corrections are made for ambient water temperature and barometric pressure. A total of twenty-eight tests were conducted using two different jet pumps and seven types of static mixers. Each combination of jet pump and static mixer was tested at two operating pressures: 20 psig and 50 psig. The results indicated that there were significant differences in aeration efficiency based principally on the water pressure. All systems transferred more oxygen when operated at 50 psig. Differences between the two jet pumps and four of the mixers do not appear to be significant. The Standard Oxygen Transfer Rates (SOTR) for the best jet pump/static mixer combinations are comparable to those cited by manufacturers of mechanical type aerators.
Acids; Mining-industry; Metals; Metal-compounds; Metal-mining; Oxidation; Laboratory-testing; Sulfites; Waste-treatment
IH; Conference/Symposia Proceedings
Mine Drainage and Surface Mine Reclamation. Volume I: Mine Water and Mine Waste
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division