Buoyed by $1.4 million in state aid to remediate water and ground pollution, a partnership of developers said Thursday that it expects to break ground next year on 175 new apartments, several retail spaces and a medical office building in Plainville’s town center. Connecticut has now put a total of $2.

6 million into cleaning up the 15-acre property that was once the headquarters of the now-defunct White Oak Construction. A partnership of Manafort Brothers Inc. and the Newport Realty Group said Thursday that once the last stage of environmental work is completed next year, contractors will begin on the ambitious job.

The project is a major boost in a town where business leaders have been frustrated for more than 20 years as White Oak’s two-story buildings with nearly 50,000 square feet of space have loomed – empty and boarded-up – over the prime intersection in the town center. “We see this as a once in a lifetime opportunity to spur some belief in development in our core downtown area and truly see it as a catalyst for further public and private investment,” Economic Development Coordinator Cal Hauburger said at a brief press conference outside the building. “For the past two decades this property has sat vacant, under-utilized and contaminated in our core downtown area without contributing to our tax roll and just being a general eyesore for our community,” he said.

The funding for Plainville was part of a $26.3 million package of brownfield remediation grant.