Sierra Vista staff propose phased sewer and refuse rate increases to pay for urgent plant upgrades

City of Sierra Vista staff presented council members with a package of wastewater treatment plant upgrades and corresponding rate and fee changes during a work session, saying the city must act to avoid equipment failures and regulatory penalties.

Bryce Kirkpatrick, the city—s external operations manager, told the council the city—s wastewater operation-and-maintenance costs have risen sharply and critical plant components are at the end of their useful lives. He described a recent liner failure in an anoxic basin and said the geomembrane liners installed during the 2011 upgrades have a roughly 10-year expected life. "We did have a liner fail as you all may know last summer in our Anoxic Basin," Kirkpatrick said. He told council staff recommend replacing basin liners with shotcrete, which has an estimated life of 20 to 25 years, add a third clarifier to expand capacity, and add disinfection (likely chlorination) because the Arizona regulator will require it if the city changes treatment processes.

Why it matters: staff and the finance director said the work is needed to keep the plant in regulatory compliance, maintain treatment capacity and avoid emergency repairs or consent orders that could halt development. The project is expensive; consultants and council members discussed preliminary total cost estimates in the tens of millions of dollars and the need to phase work and seek grant or public-private alternatives.

What staff proposed and why - Plant components at risk:…