Considerations and operational challenges in choosing Membrane Filtration for a Water Treatment Plant Upgrade

Ed CrossDivision Manager, Water Supply and TreatmentTwo Rivers Utilities

Keith Garbrick, PEVice PresidentLabella Associates, PC

November 16, 2015

Agenda

•Overview of TRU’s Facility•Overview of Membrane Technology•Permitting Membrane Technology•Process Considerations•Start-up Considerations•Conclusion

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

TRU Facility - Existing

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

TRU Facility – Proposed

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

Membrane Technology

UF – 0.02 micron nominal pore sizePVDF Chemistry

Oxidant resistant (500,000 ppm-hr Cl2)

Wide pH operating rangeFiltration: 5 to 9.5 pHCleaning: 2 to 11 pH

Outside/In flow pathCompatible with coagulants & oxidantsOperate at 95-96% recovery

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.

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!

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 •2nd Stage Membrane Filtration (99% recovery)•3-D Design Tools

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

Questions and Answers!

“Coming together is a beginning.Keeping together is progress.Working together is success.”

~Henry Ford