Fairhope hears $40M plan to add redundancy, reduce odors at wastewater plant

Fairhope — City officials and consultants on Feb. 9 reviewed a multi‑phase plan to modernize the Fairhope wastewater treatment plant, pursue redundancy in treatment systems and reduce ongoing odors and maintenance costs.

"Your average daily flow is around 2.2 MGD," consultant Caleb Leach of Krebs Engineering told the council, adding that peak storm flows can reach about 10 MGD. Leach described a staged approach that would increase average treatment capacity to roughly 6 MGD in the initial phase, with design margins and piping sized to allow an eventual 8 MGD average and peak-day capacities up to 18 MGD.

The proposal focuses on reusing existing tanks where feasible, converting older digesters to biological treatment basins, adding a third clarifier and replacing outdated filter and aeration equipment with newer, less proprietary systems. Leach said the plan includes a new blower and electrical building, upgraded instrumentation and a centralized odor-control system covering the headworks and digesters.

Leach gave a ballpark cost for the on‑site, phased improvements as "just shy of $40,000,000," and said a greenfield plant with a second permitted outfall into Mobile Bay could cost on the order of "$100,000,000." He argued the on‑site approach avoids the capital and long‑term operating costs of a second full plant.

Council members raised detailed questions about sizing and alternatives. "We seem to be designing a system that we will never need as far as the capacity," said Councilman Burrell, pressing whether the city should invest more in infiltration‑and‑inflow (I&I) reduction instead of building larger hydraulic capacity. Leach responded that filter and disinfection equipment must be sized for peak hydraulic flow and that the project's emphasis is largely on building redundancy for maintenance and permit compliance rather than immediate biological‑treatment capacity alone.

Engineering staff also told the council the headworks work, which adds a vortex grit removal system and a second screening channel to provide redundancy, is due to start up later this spring. The consultants recommended cloth‑disc filters (gravity flow) to replace older, sole‑source 'fuzzy' filters and said that moving from many small motors to three enclosed blowers would cut noise and maintenance needs.

Council members asked for further cost breakdowns, comparisons of the lifecycle costs of the two approaches, and more detail on how the service territory and infill assumptions drove the 8 MGD planning number. "If we can reduce infiltration by millions of gallons a day, that may be the more cost‑effective option," Burrell said.

Next steps: staff said they will provide more detailed itemized estimates, additional modeling of I&I scenarios and a phasing schedule for council review before any construction contract is awarded.