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Combined sewer overflows: an environmental source of hormones and wastewater micropollutants

July 26, 2012

Data were collected at a wastewater treatment plant (WWTP) in Burlington, Vermont, USA, (serving 30,000 people) to assess the relative contribution of CSO (combined sewer overflow) bypass flows and treated wastewater effluent to the load of steroid hormones and other wastewater micropollutants (WMPs) from a WWTP to a lake. Flow-weighted composite samples were collected over a 13 month period at this WWTP from CSO bypass flows or plant influent flows (n = 28) and treated effluent discharges (n = 22). Although CSO discharges represent 10% of the total annual water discharge (CSO plus treated plant effluent discharges) from the WWTP, CSO discharges contribute 40–90% of the annual load for hormones and WMPs with high (>90%) wastewater treatment removal efficiency. By contrast, compounds with low removal efficiencies (<90%) have less than 10% of annual load contributed by CSO discharges. Concentrations of estrogens, androgens, and WMPs generally are 10 times higher in CSO discharges compared to treated wastewater discharges. Compound concentrations in samples of CSO discharges generally decrease with increasing flow because of wastewater dilution by rainfall runoff. By contrast, concentrations of hormones and many WMPs in samples from treated discharges can increase with increasing flow due to decreasing removal efficiency.

Publication Year 2012
Title Combined sewer overflows: an environmental source of hormones and wastewater micropollutants
DOI 10.1021/es3001294
Authors P. J. Phillips, A.T. Chalmers, J.L. Gray, D.W. Kolpin, W.T. Foreman, G. R. Wall
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Science & Technology
Index ID 70038265
Record Source USGS Publications Warehouse
USGS Organization New York Water Science Center