Prep work has started along the Bangor waterfront, for a project that’s been nearly a decade in the making.In the coming days, work will start in earnest to rid the water there of coal tar deposits, left over from the area’s industrial past.City engineer Jim Ring says the coal tar that’s in the river has been there a while.”It’s a product of 100 years or so of commercial activity, the gas plant, and some of the handling of the by-products that ended up in the river,” Ring says.Coal tar contaminants can be toxic during prolonged contact or if injested. “It’s enough of a risk that we feel and others feel it needs to be dealt with,” he says.For 11 years, the city has been working with a Wisconsin-based environmental consulting group to decide how to address it. In the coming days work starts on a two-phase project – first, dredging the river. “We’re going to be dredging up several thousand yards of materials to get it out of the river before we do the cap construction. That disturbance is going to release odors,” Ring says.”A smell that will be like asphalt and mothballs. It’ll be a heavy, oily smell,” says Eugene McLinn, a consultant for RMT, Inc.They say the 15 days of dredging could produce that smell. Potentially strong, it will be monitored to make sure it’s within safe levels.”And the tar we don’t remove here, stays within the cap,” Ring says.Then they plan to build a sloped roof of sorts underwater to cap off the contaminated area, with a vent to the side, out of the public way.”This is actually a cap that was developed for this project and we’ve applied for a patent for it,” McLinn says.They’ll be working on an area just more than an acre, which officials say has 98-percent of the contamination. It’s a 7-million dollar project, paid for mostly through settlement funds from companies a judge ruled was responsible. “I’m very glad we’re finally to this point,” Ring says.Construction should last around three months.The city is holding a public meeting Wednesday night to talk about the project and the odors expected during construction. The meeting starts at 6:30 at Bangor Waterfront Park, which is located at the corner of Front and Railroad streets.