By Courtney Swyden
Endocrine disrupting compounds (EDC) that remain in the water after wastewater treatment are a concern and were researched by a Southern Methodist University graduate student.
EDCs are chemicals that, in small doses, can interfere with normal hormone production, and can affect the endocrine system in humans and wildlife. SMU environmental engineering graduate student Adrian Dongell and his advising professor, Dr. John Easton, researched various removal strategies of EDCs.
“Any effect on this system [endocrine] could cause reproductive and/or health effects,” said Dongell, a recipient of a $5,000 2004-05 Texas Water Resources Institute research grant.
In this study, Dongell collected water samples on a monthly basis for one year at the Dallas Central Wastewater Treatment Plant (WWTP) to determine the levels of hormones entering and leaving the plant. The steroid hormones that he included in his study were 17ß-estradiol (E2), progesterone, and testosterone.
In the laboratory, Dongell constructed a bench-scale flow-through system to evaluate the removal of hormones at a typical WWTP. The system included four identical activated sludge reactors, like that of a typical WWTP that treats the waste. A sedimentation tank was used to remove the remaining sludge. Each reactor was operated at different food-to-microorganism (F/M) ratios to achieve a typical range of solids resistance times to study the degradation of hormones.
Dongell operated the units for 10 days to achieve steady-state operation, followed by six days of hormone data collection. The hormone removal range was from 60 percent to 93 percent across the four reactors. He also observed that the hormone removal rate increased with decreasing the F/M ratios.
He hopes that his findings will promote more researchers to explore other EDC treatment options.
“Activated sludge treatment alone is unlikely to provide enough removal to comply with future regulations of hormone discharges in municipal WWTP effluents, which are designed to protect sensitive aquatic species,” said Dongell.
Dongell, originally from Scottsdale, Arizona, is currently residing in Dallas, Texas and is working for Weston Solutions, Inc.
Dongell’s research was funded by TWRI through the U.S.Geological Survey, as part of the National Institutes for Water Research annual research program. TWRI is the federally designated institute for water resources research for Texas.
For more information on Dongell’s research, visit “USGS Research Grants.”
