Year Established: 2012 Start Date: 2012-03-01 End Date: 2014-02-28
Total Federal Funds: $14,000 Total Non-Federal Funds: $30,494
Principal Investigators: Paige Novak
Abstract: Micropollutants are compounds that are present in the environment at very low concentrations. Endocrine disrupting compounds (EDCs) such as steroid estrogens (e.g., estrone, E1) or bisphenol A (BPA) are a subset of micropollutants that cause potentially devastating developmental or reproductive harm to aquatic life at environmentally-relevant concentrations. Biological treatment is the principal removal mechanism for many EDCs and other micropollutants in municipal wastewater treatment systems, including E1 and BPA. In fact, both of these compounds can be biodegraded efficiently under aerobic conditions, but removal rates have been shown to be highly variable between treatment plants and even within the same treatment plant over time. This suggests that there might be ways to design and operate treatment plants to optimize removal of these compounds. Interestingly, one of the variables that may be critical, the concentration of non-pollutant organic compounds present in the system, has not been systematically investigated with respect to its role in the degradation of many micropollutants, including E1 and BPA. Indeed, it is often assumed that organic compounds inhibit the removal of micropollutants through substrate competition; this assumption has even been incorporated into models developed to describe the biological removal of E1. It has also been hypothesized, however, that micropollutants are removed by multiple-substrate utilizing bacteria, and that the presence of other organic compounds may be beneficial to micropollutant degradation. Determining if and how non-pollutant organic compounds affect E1 and BPA biodegradation is a critical step in finding solutions for EDC, and more broadly, micropollutant, removal from wastewater. The proposed project will study the effects of organic carbon concentrations on the removal of E1 and BPA, two important EDCs in terms of their effluent concentrations and estrogenicity, that have widely varying removal efficiencies in wastewater treatment plants. The following three objectives are proposed. Objective I: Determine if non-pollutant organic compounds compete with the representative micropollutants E1 and BPA in a model wastewater system. Objective II: Determine if long-term changes in microbial community as a result of exposure to non-pollutant organic compounds affects (positively or negatively) biodegradation of E1 and BPA. Objective III: Determine if the presence of non-pollutant organic compounds increases the removal rate of E1 and BPA, implying that mixed-substrate organisms are active, at least in part, in micropollutant degradation.