Passive Treatment and Monitoring at the Standard Mine Superfund Site, Crested Butte, Co

Abstract

At the 2008 ASMR conference, data from the initial two months of operation of a U.S. EPA pilot biochemical reactor (BCR) was reported. The BCR was designed and constructed in August, 2007 to treat mining influenced water (MIW) emanating from an adit at a remote site in southern Colorado. The original objective of the study was to operate and monitor a BCR on a year-round basis in a harsh mountain environment. In the second year, a pilot chitin reactor was constructed for manganese removal. The treatment results from 13 months of BCR operation and 2 months of chitin reactor are presented. The treatment goal for the two pilot reactors was to determine compliance with the applicable surface water quality standards for the State of Colorado. Several attributes of the treatment and monitoring system were unique. It was constructed at an elevation of 11,000 feet a.m.s.l. (3,353 meters), was designed to operate year-round, and was totally passive, using solar energy for the monitoring system and pump power. Due to the site being inaccessible during winter months, this remote monitoring system was designed to collect samples and monitor field variables through the winter months. Field variables were measured and stored by Hydrolab™ sondes. Influent and effluent water quality samples were collected and stored in Teledyne™ ISCO™ 6712 samplers. For the first year of operation, the field variable data were transmitted via Stratolink™ satellite communicators. Due to operational issues, the Stratolink™ units were replaced with satellite phones in September 2008. The contaminants of concern (COCs) in the MIW are cadmium, copper, iron, lead, manganese, and zinc. BCR metal removal rates averaged approximately 98% over the first year of operation for cadmium, copper, lead, and zinc. Despite these high removal rates, the BCR effluent exceeded the applicable water quality standards for cadmium, lead, and zinc. Iron and manganese removal rates varied over the first year of BCR operation and were not sufficient to achieve the applicable water quality standards. The removal of manganese by the chitin reactor was inconsistent with an average percent removal rate of 23% over the first two months of operation. Since data are limited on biochemical and chitin reactors operating in elevated and harsh winter locations, the acquired data are unique for MIW remediation.

Passive Treatment of Mining Influenced Wastewater With Biochemical Reactor Treatment at the Standard Mine Superfund Site, Crested Butte, Colorado

“…Adit discharge was delivered through two four inch PVC pipes to a surge anticipation tank and was fed to the reactor by a small intermittently operating solar powered pump. Hydraulic residence time within the reactor is approximately 31 hours (Reisman et al, 2009). BCR influent flow was measured by a flume and ISCO 730 bubbler Module™.…”

“…Previous studies involving post treatment polishing of the Standard Mine pilot BCR effluent have examined a chitin reactor for polishing of Mn (Reisman et al, 2009), a four cell aerobic polishing cell (APC) for polishing of Fe, Mn, organics, and nutrients, and a mixing study exploring blending BCR effluent and untreated adit discharge to examine residual treatment capacity of BCR effluent. The mixing study evaluated reducing the metals and acidity load associated with the MIW, reducing the biochemical oxygen demand (BOD) and sulfide concentrations of the BCR effluent, and ultimately reducing the footprint requirements for a passive treatment system utilizing BCRs (Smart et al, 2010).…”

35 years of lessons learned designing, building, and monitoring passive treatment systems for mining influenced water (part 1)

“…Pilot flow: 3.8 L/min. Site summary: Until the 15ha backfilled and reclaimed surface coal mine was remediated in 2019 at a cost of about $US 7 million [22] , the seepage from this site was considered to exhibit the worst acidic chemistry in the State of Pennsylvania [Figure 9, left]. Its effluent destroyed nearly 10 km of three otherwise pristine streams which are tributaries of the Susquehanna River.…”

Pilot-scale passive bioreactors for the treatment of acid mine drainage: Efficiency of mushroom compost vs. mixed substrates for metal removal

“…In fact, laboratory column-reactors tested for short periods of time (less than 6 months) do not provide pertinent data applicable to field-scale treatment systems. As a leading example, the chitinous materials, which apparently seemed to be the most promising substrate for Mn retention in laboratory passive systems (Robinson-Lora, 2009), failed to provide consistent results at a larger pilot-scale (Reisman et al, 2009).…”

“…In addition, crab-shell chitin (high in carbonates and phosphates) was reported as a multifunctional (sorption media and substrate) amendment, offering significant benefits to a mushroom compost-limestone-based bioreactor, especially for Mn removal, when added in fractions of 50e100% (Robinson-Lora, 2009). However, highly variable Mn removal efficiencies have been reported in the literature, ranging from 23% (Reisman et al, 2009) to 86% (Venot et al, 2008) in pilot-scale testing. Apparently, these inconsistent results are related to the types of organic substrates used and to AMD quality and flow rate (Guo et al, 2001;Neculita et al, 2011).…”