The Effects of an Antimicrobial on Anaerobic Digestion Microbial Communities

Over two hundred metric tons of micropollutants are discharged to the environment with biosolids each year in the U.S. Of particular concern is the antimicrobial agent triclosan, which accumulates under methanogenic conditions in wastewater treatment plants. Experiments were setup to test the impacts of triclosan on methanogenic community structure and function. Microbial communities that had not been exposed to triclosan were able to adapt to triclosan at environmentally relevant levels and maintain function. However, when communities with previous exposure to triclosan were amended with triclosan at approximately four-fold current environmental levels, their community structures shifted and methane production was cut in half.