EVALUATION OF AERATION TECHNIQUES FOR MINE WATER TREATMENT IN PASSIVE SYSTEMS

摘要

Removal of metals from mine drainage involves a host of chemical and biological processes including oxidation and hydrolysis reactions. The rate of reactions is dependent on mine water pH, presence of bacterial catalysts, and the availability of oxygen. Oxygen availability becomes particularly important in treatment systems using aerobic processes such as settling ponds and wetlands. Although oxygen is readily available in the atmosphere, encouraging the transfer of oxygen to mine water can be a challenge. Applicability of the various methods to increase oxygen levels in mine water is dependent on mine water chemistry and the availability of treatment area, hydraulic head, and power. Innovative aeration techniques have been developed which use wind, water, and electricity as power. The suitability of techniques must be evaluated on a site-by-site basis. Wind energy has been harnessed using windmill aeration techniques at the Sagamore site in Fayette County, Pennsylvania. Water energy has been utilized through manipulation of available hydraulic head to improve aeration as demonstrated at the Kolb site in Indiana County, Pennsylvania. In cases where adequate aeration cannot be accomplished by passive methods, such as the Kempton site in Garrett County, Maryland, active mechanical aeration using electric power may be a cost-effective alternative.