RECLAMATION OF WASTEWATER FROM A MUNICIPAL WASTEWATER TREATMENT SYSTEM: A TOXICOLOGICAL STUDY OF EFFLUENT BLENDS EXAMINES THE POTENTIAL REUSE OF BRINES
Abstract:In order to meet the increased demand for freshwater resources by urban and industrial consumers, municipalities have begun to focus on water reclamation issues. The Orange County Sanitation District has initiated studies to examine various options for reclaiming freshwater from treatment plant operations in order to transfer reusable portions to recharge underground aquifers. The “brines” produced by the reverse osmosis treatment of wastewater may be added to future effluent blends for eventual discharge into marine receiving waters. We conducted a series of toxicological studies to examine the effects of six effluent treatment blends that included brine components on freshwater and marine organisms typically used in effluent toxicity tests. Results for the marine species Atherinops affinis and Stronglyocentrotus purpuratus indicate that each of the blends and the 24-hr composite final effluent tested had no measurable effect under marine conditions. Dilutions of approximately 31:1 would be required to remove the effects documented with these bioassay tests; therefore the effluent blends tested would meet all current criteria for discharge into marine waters. Although effluent blends were generally more toxic to the freshwater test organisms Pimephales promelas and Ceriodaphnia dubia, only five of the 24 treatments did not meet the discharge NPDES requirement of <1.5 toxic units. Examination of potential confounding factors revealed a significant response of freshwater test organisms to total or un-ionized ammonia; however, the response was greater than predicted per unit of ionized and un-ionized ammonia indicating the presence of additional toxicants. The response of these organisms to water hardness was more evident and suggests that water hardness may affect ammonia related toxicity. This influence apparently compounds toxic responses and needs to be considered when developing toxicity test strategies that examine the effects of ammonia. Freshwater test results suggest that the presence of higher concentrations of activated sludge or brine may be protective and appear to reduce effluent toxicity related to ammonia and water hardness.
Document Type: Research Article
Publication date: 2002-01-01
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