Persistence of Contaminants from Wastewater Discharges During Drinking Water Treatment: Identification of Compounds and Degradation/ Disinfection Byproducts, Evaluation of Removal, and Potential Exposure
To determine the effect of different drinking water treatment technologies on compound removal by examining the occurrence and fate of pharmaceuticals and other wastewater derived compounds through drinking water treatment.
Compounds in wastewater discharged from a treatment plant or septic system have the potential to end up in surface or groundwater that may ultimately be used as a source of drinking water. Two different sampling plans will be implemented to determine the presence of these chemicals in drinking water. In Phase 1, the source and finished waters of 9 - 15 drinking water treatment plants, known to be impacted by wastewater, will be sampled. The residence time of the plant will be taken into account during the sampling to give meaningful estimates of removal. The samples will be analyzed using existing USGS methods for pharmaceuticals and wastewater compounds, as well as by two new methods currently under development at the USGS. The first new method will consist of pharmaceuticals not currently included in the existing methods; the second will focus on chlorination and degradation byproducts of wastewater contaminants. Phase 2 will be a more intensive investigation of two to four drinking water treatment facilities. Residence time-weighted samples will be collected throughout the treatment train to obtain an understanding of the removal efficiency at each treatment step; the samples will be collected seasonally, to determine if there are changes in: (1) the number and concentrations of compounds present in the source water; and (2) treatment efficiency over the course of a year.
This work will assist the USEPA's Office of Water in determining which compounds should be included in future Unregulated Contaminant Monitoring Regulation (UCMR) sampling plans. Knowledge of the occurrence and persistence of these compounds will become increasingly important in the future as the demands on potable water sources increase and communities turn to approaches such as water reuse to supplement their drinking water supply.
Susan Glassmeyer at email@example.com