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EVALUATION OF THE REMOVAL OF ESTROGENS THROUGH THE COAGULATION PROCESS
Citation:
SCHENCK, K. M., D. WILLIAMS, N. DUGAN, H. MASH, T. F. SPETH, L. ROSENBLUM, T. WIESE, AND B. MERRIMAN. EVALUATION OF THE REMOVAL OF ESTROGENS THROUGH THE COAGULATION PROCESS. Presented at OW/ORD SEMINAR SERIES, CINCINNATI, OH, October 10, 2007.
Impact/Purpose:
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Description:
A number of estrogenic compounds have been shown to be present in surface waters in the U.S. These compounds have the potential to act as endocrine disrupting chemicals (EDCs), leading to concern over the possible presence of EDCs in finished drinking waters. Consequently, it is prudent to explore if strategies already employed to manage other drinking water risks can also control risks associated with EDCs. Coagulation is a unit process used by the majority of surface water treatment plants in the U.S. Adsorbents such as powdered activated carbon (PAC) and oxidants such as chlorine are commonly added during coagulation to enhance the removal of organic contaminants, control tastes and odors, and suppress microbial activity. Bench-scale studies (jar tests) were conducted to evaluate the ability of coagulation, alone and in combination with PAC or chlorine, to remove three estrogens (estradiol, ethynylestradiol, and estriol) from Ohio River water. The estrogen removals following addition of coagulant alone were not significantly different from zero. The addition of PAC resulted in removals ranging from approximately 20 to 80 percent. Treatment of the estrogens with chlorine, either alone or with coagulant, resulted in approximately 98 percent reductions in the concentrations of the parent estrogens. This reduction is due to chemical transformation of the estrogens. Based on an in vitro bioassay for the detection of estrogenic compounds, the chlorination by-products do not appear to contribute to the level of estrogenic activity present in the treated waters.