The Colusa City Council earlier this month contracted with SF Metalworks to repair the UV channel at the wastewater treatment plant, to solve the increase in total coliform bacteria the city has found in recent months.
City officials said the city has been getting total coliform readings of 2.2 mg/L, which is higher than the 1.8 mg/L allowed by the state.
Coliforms are common bacteria that can easily get into groundwater used for drinking from wastewater plants and other sources.
City Manager Jesse Cain said violations come with minimum fines by the state, but water quality officials will allow the city to fund repairs in lieu of paying penalties.
Although the city typically recoats the UV channel, the channel is getting worn out and would still need to be updated, officials said.
SF Metalworks, a local fabrication company, is inserting a new stainless-steel insert into the UV channel that will be custom built on the site and should result in a proper seal and flow rate, Cain said.
The cost for the insert will be $87,302. If installed correctly, the city would get about 20 years of service, which is far longer than an epoxy seal.
Cain said additional upgrades will be made on the 14-year-old wastewater treatment plant in the near future, including changing the now unsupported control system on the filter system to new standards later this fall or winter.