Challenges in Design and Construction of a Large Multi-Cell Passive Treatment System for Ferruginous Lead-Zinc Mine Waters

Abstract

Artesian discharges of net alkaline, ferruginous waters from abandoned underground lead-zinc mines cause considerable surface water degradation at the Tar Creek Superfund Site, part of the historic Tri-State Mining District of Oklahoma, Kansas and Missouri. Two perennial borehole discharges, identified as the lowest elevation mine water discharge points in the district, have flowed unabated for almost 30 years and considerably degraded the physical, chemical and biological integrity of a first-order tributary to Tar Creek. Based on a comprehensive water quality and quantity characterization study, a large multi-cell passive treatment system was designed to receive approximately 1000 L/minute of mine water flowing from these abandoned boreholes (pH 5.95±0.06, total alkalinity 393±18 mg/L CaCO 3 , total acidity 364±19 mg/L CaCO 3 , Fe 192±10 mg/L, Zn 11±0.7 mg/L, Cd 17±4 ug/L, Pb 60±13 ug/L and As 64±6 ug/L). The objectives of this project include: i) remediation of polluted mine waters to acceptable quality for maintenance of the receiving water body aquatic community, ii) demonstration of the first mine water treatment facility of any kind in the Tri-State Mining District, and iii) technology transfer to speed application of this technology to other locations. The passive treatment system includes an initial oxidation pond followed by parallel treatment trains (to facilitate research and experimentation) consisting of aerobic wetlands, vertical-flow bioreactors, re-aeration ponds (with active aeration via wind and solar power) and horizontal-flow limestone beds. Waters from the parallel trains are recombined in a polishing wetland prior to final discharge. Total design surface water elevation change in the entire system is approximately 1.8 m. Prior to system implementation, the abandoned boreholes required rotosonic over-drilling to establish hydraulic control. In addition, diversion of storm water flows from an approximately 470-ha upgradient watershed was necessary. During construction, a third mine water discharge was discovered and incorporated into the design. This system represents a state of the art ecological engineering research site for passive treatment of mine waters.

Iron and Trace Metal Retention in Net Alkaline Co2-Rich Mine Waters via Aerobic Processes

“…Water quality at the discharge has been well-documented (Nairn et al 2009, Nairn et al 2010a; Nairn et al 2010b; Table 1). …”

Assessment of Bed Hydraulics and Metal Loadings in a Passive Vertical Flow Bioreactor in Commerce, Oklahoma

“…The VFBR C3S occupies an area of 774 m 2 with an approximate water depth of between 1.0 and 1.5 m. It was constructed with a 0.46‐m thick layer of organic substrate (composed of approximately 45% spent mushroom compost, 45% hardwood chips, and 10% manufactured limestone sand, hereafter referred to as SMS) underlain by a layer of limestone gravel containing perforated pipe networks to collect the treated water and deliver it to the next pond in the treatment system (Nairn et al ). The gravel is underlain by a low permeability geotextile liner.…”

“…Geochemical sampling has since shown that when the contaminated mine water arrives at the surface, it contains notable concentrations of iron (192 mg/L), cadmium (0.015 mg/L), lead (0.067 mg/L), nickel (0.91 mg/L), arsenic (0.064 mg/L), and zinc (8.24 mg/L). Aluminum, cobalt, and manganese are also present in trace amounts (Nairn et al ).…”

Assessing the Benefits of a Passive Treatment System for Mine Drainage in Northeast Oklahoma Using Emergy Analysis

“…Re-aeration is achieved using solar-and wind-powered aerators. The PTS design and construction cost $1.2 million and has a design life of 30 years (Nairn et al, 2009). In contrast to active treatment systems (ATS), this PTS has effectively removed contaminants of concern in its first year using renewable energy sources for operation, rather than fossil fuels.…”