Reduction of Specific Conductivity in Coal Mine Effluent Using Membrane Technology

Abstract

In recent years, researchers have reported a correlation between specific conductivity (SC) and total dissolved solids (TDS) and the health of aquatic organisms in receiving streams near coal mine valley-fill structures. Due to the potential for regulatory limits on SC and TDS, coal mining operations have begun to explore treatment technologies that could be used to reduce the levels of SC and TDS in receiving streams. Nanofiltration was evaluated based on its ability to reduce SC and meet a proposed limit of 500 S/cm for mine water samples with moderate and high levels of SC from southwestern VA. Three nanofilters (NF270, DK, NFX) were tested without any pretreatment in the first phase of this project. The DK and NFX nanofilters were able to meet this SC limit for both mine waters tested with an average reduction of 84 percent for both mine waters tested. The NF270 nanofilters tested provided for an average SC reduction of 69 and 59 percent for the moderate and high SC mine waters tested, respectively. Performance in terms of SC reduction declined as ion concentrations increased in the influent tested. In the second phase of this project, microfiltration and simulated-sand filtration were introduced as a pretreatment stage in order to determine if SC reduction could be enhanced. Neither of the pretreatment options improved the SC reductions accomplished by nanofiltration.

Instream barriers contribute to population isolation of a small‐bodied, benthic, headwater‐specialist fish (Percidae)

“…The coal mines located in the headwaters of Red Bird River contribute to the high conductivity observed throughout the river's mainstem (U.S. EPA, 2011b), and our results indicate high conductivity is the leading cause of genetic isolation among proximate tributary populations in this system (Figure 1a). Newer reclamation practices that involve nanofiltration of mining effluent reduce conductivity levels (Kemak et al., 2018; Vendrell‐Puigmitja et al., 2020). Conducting such reclamation efforts at these mined sites could help reduce the conductivity in the mainstem, potentially leading to an increase in population connectivity.…”