A desktop study was performed to screen various treatment process changes, focused around membrane treatment, for future filtration enhancement to meet current and expected future regulatory limits and improve quality of water for county customers. A detailed plan and protocol for completion of bench scale and pilot scale studies were developed and executed as part of the feasibility study. Water quality goals and parameters were established to guide the process configurations and protocol development. Of critical importance and interest were treatment steps required to address membrane concentrate to minimize, to the extent possible, water loss during the treatment steps. Treatment processes considered for filtration enhancement and concentrate management, and evaluated through the bench-scale and pilot study included:
- Low Pressure Reverse Osmosis
- Biologically Active Filtration
- Ion Exchanage using MIEX
- Enhanced Coagulation
- Enhanced Powered Activated Carbon
The Pilot Study Report recommended that Manatee County retrofit the existing multi-media filters to submerged UF – something that has never been done in Florida and that would be the largest UF retrofit project implemented to date in North America.