PERFORMANCE OF CONSTRUCTED WETLANDS FOR TREATMENT OF ACID MINE DRAINAGE IN OHIO

Analyses of water quality data from seven acid mine drainage treatment wetlands in Ohio indicate that these systems display large variances in pollutant treatment efficiency and frequently fail to meet acceptable discharge limits. All systems are found to have unique designs, hydrologic loads and pollutant loads. Systematic monitoring of these systems is lacking. Historical monitoring data are sporadic and vary in the type and frequency of sampling. Multi-cell systems appear to efficiently remove iron and to slightly buffer pH. Other loads (Mn, Ca, Na, K, Mg, Si, Al, SO4, Cl, OH) display little or no statistically significant change. Seasonal data are available for several wetlands but display no statistically relevant trends. Acid mine drainage in southeastern Ohio is generated in active and abandoned mines and is associated principally with surface mining of coal deposits. These wetlands have been located and mapped with data assembled in a Geographical Information System (GIS). Wetlands are grouped by pollution reduction objective, by similarity of local geology and by similarity of hydrologic setting. Geochemical monitoring data are being analyzed for spatial trends and to assist in evaluating the effectiveness of these systems in treating acid mine drainage. A web site is under development that will house an index of all of the known constructed wetlands in Ohio with their locations, physical data (hydrologic, geologic, geophysical), chemical data, and related biological information so that the data are available for government and public use.