EPA 910-R-07-002 Alaska United States Region 10 Idaho Environmental Protection 1200 Sixth Avenue Oregon Agency Seattle WA 98101 Washington Office of Water and Watersheds April 2007 Advanced Wastewater Treatment to Achieve Low Concentration of Phosphorus Advanced Treatment to Achieve Low Concentration of Phosphorus April 2007 EPA Region 10 Acknowledgements EPA is very grateful to the operators and managers of the wastewater treatment plants included in this evaluation. Without their time and assistance this project would not have been possible. A special thank you goes to Magali Prevost who donated her time to help EPA Region 10 staff conduct the evaluation and complete this report. EPA also expresses appreciation to the following individuals who assisted by providing facility information or review of the project report: Dave Pincumbe, EPA-Region I Ken Merrill, Washington Department of Ecology Laurie Mann, EPA-Region 10 Ken Kosinski and Robert Wither, New York Department of Environmental Conservation Jon Gasik and Tim McFetridge, Oregon Department of Environment Quality Dr. Remy Newcome, University of Idaho, Moscow and Bluewater Technologies Inc. Bonnie Beavers, Center for Justice Kathleen Suozzo, Delaware Engineering Project Manager And Report Writer David Ragsdale, Engineer EPA Region 10, Office of Water & Watersheds Web Posting Jeff Philip, Webmaster EPA, Region 10 Cover Page Christopher Moffett, Graphic Designer EPA Region 10 Photos All photos by report writer unless otherwise noted For Additional Information About This Report: David Ragsdale, Engineer EPA Region 10, Office of Water & Watersheds (360) 407-6589 Email: [email protected] - 2 - Advanced Treatment to Achieve Low Concentration of Phosphorus April 2007 EPA Region 10 Abstract In this report, EPA Region 10 presents observations of advanced wastewater treatment installed at 23 municipalities in the United States. These facilities employ chemical addition and a range of filtration technologies which have proven to be very effective at producing an effluent containing low levels of phosphorus. Observations from this evaluation include: • Chemical addition to wastewater with aluminum- or iron-based coagulants followed by tertiary filtration can reduce total phosphorus concentrations in the final effluent to very low levels. The total phosphorus concentrations achieved by some of these WWTPs are consistently near or below 0.01 mg/l. • The cost of applying tertiary treatment for phosphorus removal is affordable, when measured by the monthly residential sewer fees charged by the municipalities that operate these exemplary facilities. The monthly residential sewer rates charged to maintain and operate the entire treatment facility ranged from as low as $18 to the highest fee of $46. • There appeared to be no technical or economic reason that precludes other dischargers from using any of the tertiary treatment technologies that are employed at these WWTPs. Any of these technologies may be scaled as necessary to fulfill treatment capacity needs after consideration of site specific conditions. • Other pollutants that commonly affect water quality such as biochemical oxygen demand, total suspended solids, and fecal coliform bacteria are also significantly reduced through these advanced treatment processes. • WWTPs which utilize enhanced biological nutrient removal (EBNR) in the secondary treatment process can often reduce total phosphorus concentrations to 0.3 mg/l or less prior to tertiary filtration. While employing EBNR is not essential to achieving high phosphorus removal rates, EBNR enhances the performance and reduces operating costs (especially chemical use) of the subsequent tertiary filtration process. Recently published studies report that the longer solids retention times used in BNR processes also removes a significant amount of other pollutants contained in municipal wastewater, including toxics, pharmaceuticals, and personal care products. • The low effluent turbidity produced by tertiary filtration allows for efficient disinfection of final effluent without chlorination through the use of ultraviolet treatment. • The treatment processes and quality of the final effluent produced by tertiary filtration for phosphorus removal typically meet state criteria for wastewater reclamation. Reuse of this high quality effluent can be an attractive alternative to direct discharge into surface waters in situations where restrictive NPDES permit limitations apply. - 3 - Advanced Treatment to Achieve Low Concentration of Phosphorus April 2007 EPA Region 10 Table of Contents Acknowledgements......................................................................................................................... 2 Abstract........................................................................................................................................... 3 Nutrients and Water Quality Problems........................................................................................... 5 Evaluation considerations ............................................................................................................... 6 Summary of Observations............................................................................................................... 6 City of Aurora, Sand Creek Wastewater Reuse Plant................................................................... 11 Breckenridge Sanitation District, Iowa Hill Wastewater Reclamation Plant .............................. 13 Breckenridge Sanitation District, Farmers Korner Wastewater Treatment Plant......................... 17 Snake River Wastewater Treatment Plant .................................................................................... 19 Pinery Wastewater Reclamation Facility...................................................................................... 22 Clean Water Services, Rock Creek Advanced Wastewater Treatment Plant ............................... 26 Clean Water Services, Durham Advanced Wastewater Treatment Plant..................................... 30 Stamford Wastewater Treatment Plant ......................................................................................... 34 Walton Wastewater Treatment Plant ............................................................................................ 39 Milford Wastewater Treatment Plant............................................................................................ 44 Alexandria Sanitation Authority (ASA) Advanced Wastewater Treatment Plant........................ 47 Upper Occoquan Sewage Authority (UOSA)............................................................................... 51 Fairfax County Wastewater Management, Noman M. Cole Jr. Pollution Control Plant.............. 57 Blue Water Technologies, Inc – Pilot facility at the Hayden Wastewater Treatment Plant........ 62 CoMag™ Technology – Pilot testing at the Concord Wastewater Treatment Plant .................... 66 LOTT Budd Inlet Wastewater Treatment Plant............................................................................ 69 - 4 - Advanced Treatment to Achieve Low Concentration of Phosphorus April 2007 EPA Region 10 Nutrients and Water Quality Problems Phosphorus and nitrogen are nutrients that are essential for aquatic plant and algae growth. Most waters naturally contain enough of these nutrients to support native aquatic life. However, an over-abundance of these nutrients can over-stimulate plant and algae growth such that they create water quality problems. Over 1,000 waterbodies in Idaho, Oregon and Washington are identified as being impaired due to excessive nutrient loading and are included on state Clean Water Act 2004 §303(d) lists for water quality problems. The problems caused by nutrient enrichment of lakes, stream, and rivers are not unique to the Northwest states as many other waterbodies across the United States have also been identified as impaired by nutrients. Nutrient impairments affect the survival of many aquatic species such as salmon; affect the safety of drinking water supplies; affect the aesthetics of recreational areas, and the ability to navigate through rivers and lakes. In freshwater systems, phosphorus is typically the nutrient that is in short supply relative to biological needs, which means that the productivity of aquatic plans and algae can be controlled by limiting the amount of phosphorus entering the water. Many streams and lakes in the Northwest are documented to have very little capacity to assimilate phosphorus loading during the “critical” warm and dry summer period without significant water quality degradation. Large diurnal swings in pH and dissolved oxygen may occur as excessive amounts of nutrients are metabolized by aquatic plants and algae. The range of these swings is often measured to exceed the state water quality criteria established to protect fish and other aquatic organisms in their various life stages. Therefore, the amount of phosphorus currently entering these waters exceeds the seasonal loading capacity and must be reduced if these water quality problems are to be resolved. The sources of phosphorus loading vary depending on the human activities and conditions in a specific watershed. In the Northwest, phosphorus loading into streams and lakes from nonpoint sources (e.g. agriculture, pet waste) is often minimal during the summer months because there is typically very little rainfall runoff to flush pollutants into receiving waters. The discharges of treated wastewater can be the most significant