SMALL-SCALE PILOT TESTING OF STORMWATER TREATMENT SYSTEMS TO MEET NUMERICAL EFFLUENT LIMITS IN THE LAKE TAHOE BASIN
Abstract:To stem the continuing loss of clarity in Lake Tahoe, stringent numerical discharge requirements for storm water discharges in the Tahoe basin have been promulgated. In 2008, discharges to surface water must meet limits for turbidity (20 NTU), total phosphorus (0.1 mg/L), total nitrogen (0.5 mg/L), total iron (0.5 mg/L), and oil and grease (2 mg/L). The California Department of Transportation (Caltrans) has undertaken a multi-year small-scale storm water treatment pilot project to identify, test, and evaluate potential treatment technologies to meet the effluent limits. Treatment technologies investigated include simple “non-mechanized” sedimentation and granular media filtration systems (with and without chemicals), plus more complex “mechanized” systems involving combinations of coagulation, flocculation, sedimentation, filtration, and ion exchange. During the first two years of operation covered in this paper, thirty different non-mechanized systems and eight mechanized systems were tested. In terms of turbidity and phosphorus removals, conventional storm water treatment systems (detention and filtration without chemicals) were consistently unable to meet the discharge limits, whereas similar non-mechanized systems preceded by chemical coagulation performed much better, frequently meeting the limits. Sedimentation without chemicals followed by filtration through activated alumina or expanded shale adsorptive media also performed well in removing turbidity and phosphorus, but resulted in elevated pH and dissolved aluminum concentrations. Most of the mechanized systems were successful in meeting the turbidity and phosphorus limits, though these systems are not well suited to the roadside environment. The nitrogen limit was not consistently met by any of the systems tested.
Document Type: Research Article
Publication date: 2005-01-01
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.
WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- Learn about the many other WEF member benefits and join today
- Ingenta Connect is not responsible for the content or availability of external websites