Mine drainage and other waste waters are potential sources of contamination for many different aquatic environments. This research group will characterize the complex microbial communities during bioremediation of mining waste water by using metagenomic profiles of the microorganisms at mine drainage sites. Current waste water treatment methods require large scale chemical treatment of both metal leaching (ML) and acid rock drainage (ARD) in order for mining to be environmentally sustainable.

Bioremediation provides an alternative to chemical treatments because microbial consortia are effective in reducing metals to less toxic forms or to sequester metals as part of their detoxification mechanism. In particular, sulfate-reducing bacteria (SRB) are effective in bioremediation of mine drainage. However, SRB rely on other members of a diverse microbial community to provide them with carbon compounds and other nutrients needed to survive. Therefore, understanding the complex interactions of the microbial community is essential to implement effective bioremediation and passive treatment systems. The research group will track existing consortia over time and in changing environmental conditions to monitor the effect of different variables on microbial community composition.

This research can improve the passive treatment of water where naturally occurring biological processes are harnessed to detoxify contaminated water.

When mine rock is exposed to both air and water the metals within can cause ARD and ML that are significant contaminants to the water supplies downstream of mining sites. The current method of dealing with both ARD and ML generates a toxic sludge and requires expensive chemical plants to decontaminate the metals. Bioremediation strategies decrease the cost of treatment as well as drastically improve the effectiveness in dealing with both ARD and ML. However, current methods to monitor the effectiveness of bioremediation and the associated microbial communities are inaccurate.

In order to fully understand the complex interactions of microbial flora at bioremediation sites the group will perform metagenomic and phylogenetic profiles of the communities using microarray technology. They will assess both the diversity of the different types of microbial species as well as the impact of changing environments on community composition.

The most important microorganisms for bioremediation of mining drainage are SRB that live in anaerobic environments and produce sulfide. The sulfide produced then reacts with metals in the water to form insoluble precipitates, thus effectively removing metals and neutralizing the sulfates in the mine drainage. These SRB co-exist in microbial communities that have complex biochemical interactions and rely on each other to supply the necessary nutrients. In particular, SRB require other microorganisms to degrade complex carbon compounds into simpler sources of electrons for their metabolism. Other microorganisms such as iron-reducing bacteria are antagonistic to SRB metabolism and interfere with effective bioremediation strategies.

The balance and composition of microbial communities at bioremediation sites needs to be accurately assessed in order to fully implement effective passive treatment strategies. The effect of changing environments on the composition of microbial communities is another important variable to monitor in order to fully understand the dynamic interactions within consortia at bioremediation sites.