Columbia County to deploy UV AOP system to curb algae taste-and-odor problems

Columbia County Water Utility announced plans to bring an ultraviolet advanced oxidation (UV AOP) treatment system online next year to reduce seasonal taste-and-odor events caused by algae and to address emerging contaminants.

A Columbia County Water Utility spokesperson said algae blooms have produced recurring taste-and-odor problems and that the new system will add a layer of treatment. “This system is the first of its kind in the state of Georgia,” the spokesperson said.

The utility selected a UV AOP system after reviewing alternatives, staff said, describing the technology as a combination of ultraviolet light and hydrogen peroxide that creates hydroxyl radicals to break down contaminants that conventional treatment has difficulty removing. “It does so many other things that are not even required by the state yet, so we feel like we’re a step ahead,” a utility staff member said.

Staff provided technical details: the facility has four treatment trains, each with three banks of 16 bulbs, and the UV AOP configuration can treat 24,000,000 gallons per day on side A and 12,000,000 gallons per day on side B. The county emphasized the UV stage comes after conventional steps—coagulation/flocculation, sedimentation and filtration—and before finished chemicals such as chlorine, fluoride and phosphates.

Utility staff said the hydroxyl radicals produced by the process lyse cells that create taste-and-odor compounds MIB and geosmin and can inactivate associated odors. The staff noted the process can also treat pharmaceuticals and pesticides and other unregulated contaminants the utility expects to encounter in the future.

The utility described its startup monitoring plan: before-and-after sampling during initial operation, biweekly testing during startup that will move to monthly after verification, jar tests to optimize coagulant dosing run every two hours, and routine checks of chlorine, fluoride, phosphate and pH levels.

Construction at the Clarks Hill facility was completed earlier because staff said the lake there historically shows higher levels of MIB and geosmin; work at the Jim Blanchard plant was completed around April but staff delayed high-flow testing until conditions were appropriate. Staff warned that residents could still notice taste or odor issues this year, but said they expect noticeable improvements once the UV AOP is fully online next year.

The county characterized the system as a longer-term investment rather than the cheapest option. The utility did not provide cost figures, regulatory approvals or a firm online date beyond "next year."