Passive Treatment 101: An Overview of the Technologies
Presenter: Jim Gusek, (Golder Associates Inc.)
There are basically three kinds of passive treatment technologies for treating mining influenced water (MIW):
- Abiotic, Limestone-based methods for treating net-acidic MIW have been effective in adding alkalinity;
- Semi-biological methods that condition MIW for subsequent limestone dissolution; and
- Biologically-facilitated components to round out the list.
Some of the biological components can function without plants: Biochemical Reactors (BCRs) are typically applicable to metal mine drainage with high acidity and a wide range of metals. In contrast, Aerobic Cells containing cattails and other plants are typically applicable to coal geology derived MIW where iron and manganese and mild acidity are problematic. Most passive treatment systems employ one or more of these cell types. The track record of aerobic cells and limestone-based methods in treating coal geology MIW is impressive, especially back in the eastern coalfields of the U.S. BCRs have tremendous potential in metal mining and coal mining geological environments but have not seen as wide an application. Aerobic manganese removal cells are also amenable to sequestering heavy metals as long as iron (if present) is removed first and the MIW is circum-neutral.
This presentation compares the advantages and disadvantages the various passive treatment components and is an introduction to the wide range of remediation design options available to practitioners of passive treatment. Rather than propose “cookbook” designs, the presentation details a recommended staged-approach of laboratory-, bench-, and pilot-scale testing which has been shown to increase the likelihood of a successful design, especially for MIW with complex chemistry.
Watershed Restoration Through the Implementation of Passive Treatment Technology in the Lambert Run Watershed, Harrison County, West Virginia
Presenter: J. Brady Gutta, (West Virginia Water Research Institute)
The presentation will provide a brief history of the Lambert Run Watershed, and discuss the implementation of five passive treatment installations and their impact on water quality. A general overview of acid mine drainage (AMD) chemistry will also be provided.
MIW treatment at the Leviathan Mine Superfund Site, California
Presenter: Kevin Mayer, (U.S. EPA)
Leviathan Mine is a 250-acre abandoned open-pit sulfur mine 7000 feet high on the eastern slope of the Sierra Nevada mountain range near Lake Tahoe in California. Major environmental problems originated from open-pit sulfur mining active from 1951 through 1962. The resulting high sulfur content in the waste rocks and fractures at the mine site have been turning snowmelt, rain and groundwater into sulfuric acid, which leaches contaminants from the native minerals such as arsenic, copper, nickel, zinc, chromium along with aluminum and iron. Acid discharges from the mine severely impacted a nine-mile mountain watershed flowing into the Carson River in Nevada. Prior to recent treatment activities, a thick layer of orange precipitate coated the streambed most of the year until it washed into the East Fork of the Carson River with the high spring runoff. The presentation is a case study focusing on the three different treatment systems currently operating at the site, including lime neutralization and full-scale biological treatment systems, with significant improvement in stream water quality.