Sierra Vista staff propose major wastewater upgrades and two-year rate increases to cover aging plant work

Sierra Vista — City staff told the City Council on Monday that the city’s wastewater treatment plant needs near‑term repairs and process changes and proposed a two‑year set of rate and fee increases to pay for work.

Bryce Kirkpatrick, the city’s external operations manager, said the plant’s geomembrane liners — installed around 2012 — have an expected life of about 10 years and that one liner failed last summer in an anoxic basin. He described the proposed core work as replacing liners with longer‑lived shotcrete, adding capacity (a third clarifier) and installing disinfection if required by the Arizona Department of Environmental Quality when the plant’s permit is renewed.

Kirkpatrick said the shotcrete option has an estimated useful life of about 20–25 years and was chosen as a mid‑range cost alternative to full concrete liner replacement. “We rely on geomembrane liner basins. These liners have a roughly 10 year expected life and they were installed mostly in 2012,” Kirkpatrick said. He added that the…