Pilot-Scale Evaluation of Solid and Liquid Phase Organic Substrates Used in Biochemical Reactors for the Treatment of Mining Influenced Water

Abstract

Sulfate-reducing biochemical reactors (BCRs) were installed to provide a basis for substrate selection for a final treatment remedy for mining influenced water (MIW) from the National Tunnel adit. Black Hawk, CO. The MIW was characterized by elevated metal and SO 4 2concentrations as well as pH fluctuations from 4.8-6.4. Three pairs of BCRs were installed in 2006, each of which contained a different mixture of solid or liquid-phase substrates. The above-ground BCRs partially froze during the first winter, prompting a redesign of the hydraulic system in May 2007 and the installation of heating and insulation in preparation for the following winter in October 2007. During the hydraulic system re-design, a fourth pair of reactors that contained CHITOREM ® SC-20 chitin complex was added to provide data on an alternative solid-phase substrate.Results from 2007 suggest that nearly all of the reactors removed greater than 95% of the Fe and Zn and 50-95% of the sulfate from the MIW during September through December 2007. Copper removal was typically above 95%. In addition, chitin complex reactors demonstrated high Mn removal (average removal was 80%) and high alkalinity (average of 4200 mg/L as CaCO 3 ) during the same period. The high alkalinity was partially due to high concentrations of ammonium (up to 450 mg/L as nitrogen). Operational challenges due to winter conditions in November and December 2007 caused significant temperature and flow fluctuations; however, effective removal of metals was still observed. The BCRs will be monitored through summer 2008 and the data will be evaluated in late-summer 2008 to determine which substrates (CHITOREM ® SC-20, ethanol or solid phase organic mixture) are best suited for long-term treatment of the National Tunnel MIW by BCRs.

Effect of Organic Substrate Composition on Microbial Community Structure of Pilot-Scale Biochemical Reactors Treating Mining Influenced Water

“…The discharge contains elevated levels of sulfate and heavy metals (Zn, Cu, Mn, Cd, Pb, and As) resulting from historic gold mining. Four organic substrate conditions were studied in duplicate (further details are provided in Venot et al, 2008): Five removable mesh bags were filled with the respective substrate and stacked in the center of each reactor within a vertically placed perforated PVC pipe, in order to facilitate sampling.…”

“…In addition, quantitative polymerase chain reaction (Q-PCR) was performed targeting total bacteria, the DesulfovibrioDesulfomicrobium genera of SRB, and methanogens in order to obtain a quantitative understanding of these groups within the community. The overall effect of substrate on BCR performance is described further elsewhere in the ASMR conference proceedings (Venot et al, 2008). Thus the broader goal of this project will be to understand better the role of substratemicrobe interactions in BCR performance.…”

Bench-Scale and Pilot-Scale Treatment Technologies for the Removal of Total Dissolved Solids from Coal Mine Water: A Review

“…Chitin biologically removed SO 4 2-from CMW at bench-scale (Daubert and Brennan 2007;Korte et al 2008) and in field trials (Venot et al 2008). Daubert and Brennan (2007) used crab shells to treat actual CMW from a stream near a coal mine in Pennsylvania (USA).…”

Nuisance Constituents in Passive Water Treatment Systems– A Specific Case Study

“…anaerobically (Gusek, 2002). While there are emerging technologies that suggest Mn removal can be accomplished anaerobically with the use of chitinous materials such as crab shells (Venot, et al 2008), it can also lead to an increase in arsenic and BOD, and further research and longterm application is necessary to fully understand its use. More traditional passive treatment of Mn includes Mn removal beds and using algae to raise the pH and create manganese oxides (e.g.…”