English

Abstract

Park City Municipal Corporation (PCMC) long before being recognized as an Olympic venue was known as one of the great American silver mining towns. As a result, during a century of active mining, the Park City mining district produced millions of ounces of silver in addition to a substantial amount of mine tailing waste. As a result, the City since 1985 has been remediating these impacts with state and federal oversight. One particular challenging CERCLIS site, that was previously a historic mine tailings pond is known as Prospector Square Development (CERCLIS Listing Silver Creek Tailings UTD98051404). This site has been very challenging due to the metals that impact shallow ground water that eventually drain into the Silver Creek Watershed. To address the water quality impairment the City and Missouri University of Science and Technology teamed-up to investigate the feasibility of constructing a horizontal-flow wetland to treat this pollutant source. This effort comprised of building a pilot cell in June of 2004, leading to the construction of a full scale horizontal-flow wetland in the fall of 2008. The design of the pilot and full scale biocell was based upon lab-scale research conducted by the Missouri University of Science and Technology. In October of 2008, the Prospector Drain effluent was introduced to the system and to date analytical results reveal that the biocell is treating the Prospector Drain outfall below the Silver Creek Total Maximum Daily Load (TMDL) endpoint goals for zinc .39 mg/L and cadmium .00075 mg/L. The water chemistry of the influent, that originates from the historic silver mine tailings pond, is impaired with zinc and cadmium and has low iron with a pH of roughly 6.5. The construction of this unit encountered many challenges related to constituent relations, regulatory scrutiny, constructability, and start-up. Nonetheless, this unit since implementation is considered a success for improving water quality within the Silver Creek Watershed.