YOUNGSTOWN — The city’s board of control agreed to a 10.2% increase to a project that is diverting millions of gallons of sewage from the Mahoning River.

The board on Friday voted to pay an additional $483,841 to S.E.T. Inc. of Lowellville, which is doing the first phase of an interceptor sewer project. Most of the additional cost is for a tunnel under Norfolk Southern railroad tracks, said Charles Shasho, deputy director of public works.

With the additional work, S.E.T.’s contract is going from $4,753,539 to $5,237,380, a 10.2% increase.

The work is needed to help divert the sewage from the river and most of the cost of the two phases of the project are being covered by the state, Shasho said.

“We had some extra money in the loan we had to use,” he said. “It was either do it now or do it later.”

The city received a $4.83 million grant in July 2023 from the state, using federal American Rescue Plan funds, as well as a $4 million loan from the state that forgives the repayment of the principal to pay for much of this two-phase project.

The project replaces aging, deteriorated combined storm and sanitary sewer lines with 10,800 linear feet of 60-inch and 48-inch lines with an access road, Shasho said.

When both phases of the interceptor sewer project are finished, it will eliminate three sewer overflows that discharge about 35.5 million gallons of combined sewage annually into the Mahoning River, according to the Ohio Environmental Protection Agency.

S.E.T. started the first phase earlier this year and is expected to be finished by next month. That work goes from West Avenue to Bridge Street, near Front Street. It eliminates one sewer overflow.

The board of control on June 5 awarded a $5,235,704 contract for the second phase of this work to Rudzik Excavating Inc. of Struthers.

Rudzik’s base bid was $4,529,354 with a $706,350 add-on to install concrete encasements around the pipes near Norfolk Southern train lines.

Shasho said the city asked the rail company for a waiver for the encasements but hasn’t received a response. Both he and a Rudzik official say if the waiver isn’t given, there are less-expensive alternatives.

Rudzik is to start work on the second phase next month and have it complete by January.

That phase goes from Bridge Street to Division Street and eliminates two sewer overflows.