Wednesday 12:40 John Chermak PhD, PG Environmental Scientist, Instructor, Geosciences, Virginia Tech
Water Quantity and Water Quality Considerations for Cost-Effective Acid Rock Drainage Water Treatment
John A. Chermak, Ph.D., PG
Evaluation of water treatment options for acid rock drainage (ARD) impacted water depends on both water quantity and water quality. It is well-known how difficult and expensive it is to treat the large volumes of ARD-impacted streams typically found in mining regions. Treatment costs are also a function of the initial water quality and the desired water quality that needs to be achieved. One of the biggest challenges for successful and cost-effective treatment of these types of waters is that there is generally insufficient iron (less than 25 mg/L) present in the low total dissolved solids (TDS) waters to get nucleation and precipitation of iron oxyhydroxide after neutralization within a reasonable time frame. It is also difficult to maintain a stable solution pH value. We have found that these chemical limitations can be overcome by adding small quantities of neutralized high TDS, high dissolved iron water to the low TDS water. The high TDS water provides enough iron in solution to promote nucleation, growth, and production of adequate size floc. The ARD treatment system to be discussed is located in Eastern Tennessee and investigations started with laboratory neutralization experiments followed by a pilot scale plant, and ultimately the construction of a cost-effective full scale hydrated lime neutralization plant at the base of a 9,000-plus acre watershed. Average removal efficiencies of aluminum, cadmium, cobalt, copper, iron, lead, and zinc from the stream water were greater than 95% and concentrations achieved were lower than applicable ecological standards.
BiographyDr. John Chermak is currently an Environmental Scientist and instructor in the Geosciences Department at Virginia Tech. He received a PhD in Geology (Geochemistry emphasis)from Virginia Tech in 1989, spent 3 years in Switzerland working on applied environmental issues related to Rad-waste disposal, taught and conducted research at Georgia State University for 1 year, and has worked as an Environmental Scientist/Geochemist consultant to industry since 1993 on projects in 18 different states and 9 different countries. He is a certified Professional Geologist in the states of Virginia and Wyoming.
Areas of expertise related to mine sites include water quality and quantity issues, waste rock, tailings, pit lakes, and water treatment alternatives.
He has published more than 10 papers in refereed journals on various aspects of applied environmental issues.