U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Search Result

Mine Environment Neutral Drainage Program, 71 pp, 2019

Lab and field studies were conducted to demonstrate in-pit batch treatment of arsenic-contaminated water in mine pits using ferric sulfate. The overall objective of the investigation was to demonstrate that in-pit batch treatment of arsenic represents a viable and economical alternative to traditional water treatment applications. Phase 1 included a bench-scale study that was used to define the design criteria, including the attainable treatment efficiencies, the required reagent dosages, and the sludge production rates. Phase 2 of this study included a field-scale treatment trial that evaluated the practicality and efficacy of in-pit batch treatment of arsenic within the Night Hawk Lake Mine open pit, as informed by the results in Phase 1. Total and dissolved arsenic concentrations at 3 depths were compared pre- and post-treatment in 3 sampling events at two stations (NHP 1 and NHP2). Immediately post-treatment, total arsenic concentration at the surface at NHP1 decreased from 0.6 mg/L to 0.01 mg/L total arsenic with a dissolved concentration <0.002 mg/L for a treatment efficiency of ~98% within the surface depths. The mid-depth samples for the same sampling event were ~0.03 and 0.01 mg/L for the total and dissolved arsenic concentrations, respectively. The arsenic concentrations at depth remained close to the initial concentrations before treatment.

The Technology Innovation News Survey welcomes your comments and suggestions, as well as information about errors for correction. Please contact Michael Adam of the U.S. EPA Office of Superfund Remediation and Technology Innovation at or (703) 603-9915 with any comments, suggestions, or corrections.

Mention of non-EPA documents, presentations, or papers does not constitute a U.S. EPA endorsement of their contents, only an acknowledgment that they exist and may be relevant to the Technology Innovation News Survey audience.