CRANBERRY TWP — The township supervisors Thursday night officially approved a $64.8 million plan to upgrade the Brush Creek sewage treatment plant.

Township manager Jerry Andree said Friday that the vote is the culmination of at least five years of work by the township’s engineering staff, which researched several options for upgrading the facility.

The township was forced to renovate the facility to be in compliance with new rules and regulations from the state, and also so the plant can handle the increase of flow expected as Cranberry’s population continues to grow.

The supervisors approved a project with two phases. Construction on the first phase, which is expected to cost about $44 million, is expected to start in July 2015.

Andree said the engineering staff now will focus on permitting paperwork that must be approved by the state’s Department of Environmental Protection before construction can start.

The staff likely will work on those designs and permitting for the rest of the year, then the township likely will bid out the project in early spring 2015, Andree said.

However, Andree said all the work and planning could be derailed if the state DEP changes its rules for its permitting.

“There’s lots of detailed engineering work with getting the permit,” he said. “But the DEP won’t give specifics of what they want until we submit final drawings. Hopefully they’ll be consistent in what they told us in the preliminary phase.

“If they change anything, it could have a profound impact on our costs.”

Andree said the first phase of construction will likely last 18 months.

The project that won’t be finished until 2017.