The Butler County commissioners next week are expected to accept an arbitration award for the county’s 36 employees represented by the Probation Officers Association.

The three-year contract, which took effect Jan. 1, includes a 5 percent pay increase for 2016, a 4 percent pay increase for 2017 and a 4 percent pay increase for 2018. It expires Dec. 31, 2018.

County solicitor Mike English said because the negotiating went to arbitration, the commissioners have no choice but to accept the decision.

All contracts with the county’s bargaining units expired Dec. 31, 2014. The probation officers were the last of the units to make a deal with the county.

The county has 451 union employees.

In April, the county’s four detectives, represented by Butler County FOP Lodge 107, agreed on a three-year contract.

In May, 55 administrative professional employees represented by SEIU, Local 668, approved a four-year contract.

In August, the county accepted arbitration awards for the 98 corrections officers at the county prison and for the 10 assistant district attorneys and assistant public defenders. Corrections officers are represented by the American Federation of State, County and Municipal Employees, and the ADAs and APDs are represented by the United Steelworkers of America.

In September, the county accepted arbitration awards for the 67 court-appointed clerical and technical employees, and the 66 court-related clerical and technical workers — both represented by Service Employees International Union, Local 668.

In October, the commissioners accepted a four-year contract with the 115 employees in the administrative clerical/technical unit, also represented by SEIU, Local 668.