Times Observer photo by Brian Ferry A worker from Niagara Coatings Services prepares to paint the inside of one of the two clarifiers at the City of Warren sewage treatment plant. The work is routine preventative maintenance that will extend the life of the facility.

The City of Warren is having some of its infrastructure painted … but not for the aesthetic value.

One of the two large clarifiers at the sewage treatment plant was drained last week to prepare it for preventative maintenance. The clarifier is one of the middle steps in the treatment system.

“Sludge from the aeration tank comes in,” Sewer Plant Operator Tyler Akam said.

The heavier particles sink to the bottom of the clarifier — earning it the name “settling tank.” Floating particles are skimmed off and moved to the aerobic digester, Akam said.

Sludge eventually makes its way through the rest of the system, being stabilized and reduced in volume prior to disposal. Dewatered sludge can be taken to certain landfills or used on agricultural land where crops are not grown for human consumption.

Clarified water from the clarifier is moved to chlorine contact tanks for further cleaning, Akam said, before the water is discharged into the Allegheny River.

The maintenance work is being handled by Niagara Coatings Services of Niagara Falls, N.Y.

Painting the interior of the tank extends the life of the facility, Akam said.

The drained tank was cleaned and sandblasted to prepare it for painting.

After several coats of paint are applied, the coating will be allowed to cure before the clarifier is put back into service, Akam said.

“The plant is large enough with the low flows in the summer” to handle the input while the clarifier is out of service, he said.

The other clarifier will also be painted this year.