Tuesday, September 10, 2024
9:45 AM - 10:15 AM
Location Name
Pioneering Potable Reuse in Tennessee – Unveiling the State's Inaugural Potable Reuse Pilot
Water Resource Recovery

UNDERSTANDING DRIVERS FOR REUSE Like much of middle Tennessee, the City of Franklin has seen significant population growth over the past three decades. Most of Tennessee is rich in water resources. However, Franklin is located in the historically low-flow upper basin of the Harpeth River that experiences flows nearing 10 cfs during the summer. To meet future wastewater capacity requirements, the city is pursuing a new clean water facility (CWF) that would advance water reuse opportunities for the community. For the City of Franklin, various opportunities for beneficial reuse are available, including: • non-potable reuse for urban landscape irrigation, • river augmentation to improve baseflow and recreational benefits in the Harpeth River, and • reservoir augmentation to supplement existing raw water supplies PILOT PROGRAM DESIGN The City’s plan to evaluate the beneficial reuse of water for their community included a nine-month advanced treatment pilot program. The Franklin Demonstration Facility piloted advanced treatment technologies: membrane filtration, ozonation, biologically active carbon filtration, granular activated carbon adsorption, and UV advanced oxidation processes. These CBAT technologies demonstrate the ability to consistently produce high quality finished water that meets stringent water quality targets (organics, nutrients, and constituents of emerging concern (CECs). A rigorous 9-month test plan was developed to conduct both a long-term performance evaluation and a series of short-term challenge and spike tests on each unit process. The test plan was designed to meet the following study objectives: 1. Understand feed water quality and variability 2. Provide performance data to support the permitting process 3. Demonstrate reliable treatment performance 4. Provide performance data to support design development 5. Inform approaches for long-term operation PILOT OPERATION Keeping an advanced treatment pilot operating 24/7 for nine months required significant effort of multiple City operators and the consulting engineer. The operations team contributed to routine maintenance, process flow modifications and optimizations, and sampling efforts resulting in over 12,000 parameters measured by City, contract, and university labs. With data coming from various sources at different frequencies, data management tools assisted the quick compilation and evaluation of results. The data collected during the pilot facility operation served two primary goals: demonstrate water quality compliance and sustainability to the community and regulating authority and inform the full-scale design. Sampling efforts were extensive and included: • NPDES permit constituents • In-stream Standards for Fish and Aquatic Life and Recreation • TDEC’s Source Water Parameters • EPA’s Primary and Secondary Drinking Water Standards • Comprehensive sampling of the most common contaminants of emerging concern, including PFAS. STAKEHOLDER ENGAGEMENT The project exemplifies the value of the long-term collaboration between the City, engineers, and the regulating authority (TDEC) to define these potential reuse opportunities, select treatment technologies, and evaluate results for full-scale application. In addition to the routine touchpoints with TDEC throughout the program, the demonstration facility was beneficially used to engage with other stakeholders. Educational materials were used during pilot tours, on the City’s website, and within stakeholder meetings. The public and media were also invited to tour the demonstration facility.