1. Considerations and operational challenges in choosing Membrane Filtration for a Water Treatment Plant Upgrade Ed Cross Division Manager, Water Supply and Treatment Two Rivers Utilities Keith Garbrick, PE Vice President Labella Associates, PC November 16, 2015

2. Agenda Overview of TRU’s Facility Overview of Membrane Technology Permitting Membrane Technology Process Considerations Start-up Considerations Conclusion

3. TRU Facility - Existing Rated Capacity – 27.3 MGD 10 Train Conventional Dual Media Filtration Facility Serves a population of approximately 100,000 Produces approximately 5 billion gallons of water per year Located central to town with limited room for expansion Last significant expansion occurred in the mid 80’s

4. TRU Facility - Existing

5. TRU Facility – Proposed Rated Capacity will Remain @ 27.3 MGD Demolish North Clearwell and Process Trains 1 and 2 Install New 4 MGD Clearwell Install New Rapid Mix, Flocculators, Sedimentation Basins and Membrane Filtration capable of producing 12 MGD. Install new Chemical Feed Pumps and Bulk Storage Install new laboratory and office space Interactive 3D Design New plant wide SCADA

6. TRU Facility – Proposed

7. Membrane Technology Water molecules and dissolved salts pass freely through the membrane pores Contaminants such as bacteria and viruses can not pass through the membrane pores Semi permeable membrane wall with microscopic pores

8. Membrane Technology UF – 0.02 micron nominal pore size PVDF Chemistry Oxidant resistant (500,000 ppm-hr Cl 2 ) Wide pH operating range Filtration: 5 to 9.5 pH Cleaning: 2 to 11 pH Outside/In flow path Compatible with coagulants & oxidants Operate at 95-96% recovery

9. Membrane Technology – Pilot Testing 12 Month Pilot Program including multiple manufacturers. Goals for Two Rivers Utilities To ensure the operating parameters tested during the pilot study are aligned with the needs of Two Rivers Utilities and regulatory requirements. To determine the optimum design conditions for the membrane system based on the membrane feed water quality. To become familiar with membranes and their operations.

10. Permitting Process Membrane Justification Report including 12 months of on-site pilot testing of membrane filtration. Team approach with NC DENR being involved in preliminary engineering. Site visits to facilities currently using this technology. Full scale testing before certification of the technology. INTEGRITY TESTING!

11. Process Considerations Changes in chemical demand and type Membranes are really a facility all unto their own. Different process for conventional vs. membrane Blending of permeate from membranes and conventional filtration Redundancy 2 nd Stage Membrane Filtration (99% recovery) 3-D Design Tools

12. Start-Up Considerations Delivery schedules for receiving the membranes What do you do with all of the permeate water produced during the testing of the membranes? Substantial completion and Final Acceptance Warranty Periods

13. Questions and Answers! “Coming together is a beginning. Keeping together is progress. Working together is success.” ~Henry Ford