Passive biological treatment systems, which include treatment wetlands, are an increasingly utilized, low-maintenance option to treat mine waters and reduce their widespread impacts on aquatic ecosystems. However, despite prospective regulations to limit the electrical conductivity of mining-impacted waters, the ability of these passive treatment systems to reduce conductivity remains unclear.
A recent review in the Journal of Environmental Quality evaluates the potential of wetlands and other passive biological treatment systems to decrease the conductivity of mine waters and highlights research needs to improve the efficacy of this remediation solution.
The researchers reported that passive treatment systems can reduce conductivity of mine waters by 30–40%, but they also observed substantial variability in the reduction efficiency among systems. The use of limestone within the passive treatment systems seemed particularly associated with greater variation in conductivity changes of mine waters.
These findings may spur increased reporting of conductivity changes for passive biological treatment systems as well as improvements in system design to better harness their potential for conductivity reduction of mine waters.
Adapted from Smyntek, P.M., R.C. Wagner, L. Krometis, S. Carvajal Sanchez, T. Wynn-Thompson, and W.H.J. Strosnider. 2017. Passive biological treatment of mine water to reduce conductivity: Potential designs, challenges, and research needs. J. Environ. Qual. 46:1–9. View the full article online at http://dx.doi.org/doi:10.2134/jeq2016.06.0216