The long-awaited cleanup of the Mill River is nearing an end.

Barry Culp, senior project manager at TRC in Windsor, told the Board of Selectmen on Wednesday that removal of lead-contaminated sediment from the river should be completed by year’s end. “Our goal is to complete all of our dredging this year,” he said.

But Culp said removal of equipment from the 6.25-acre property at 2190 Post Road that was formerly home to Exide Battery Co. factory, the source of the river’s lead contamination, likely won’t be finished until the summer of 2016.

The cleanup, mandated by the state Department of Energy & Environmental Protection, divided 4,000 linear feet of the river into five sections, and the total amount of lead-contaminated sediment to be removed was estimated last year at 20,000 cubic yards.

DEEP required four sections to have a maximum lead concentration of 220 mg/kg, while one section, labeled Area 5 and the furthest upstream, could have a maximum lead concentration of 400 mg/kg., Culp said.

So far, three sections have been completed — Area 5, north of Interstate 95; Area 1, between Metro-North Railroad tracks and I-95, and Area 3, south of the Post Road, between the Post Road and the Tide Mill Dam.

Culp said post-dredging testing in those sections shows lead concentrations of 243.9 to 347 mg/kg in Area 5, with an overall score of 271.8 mg/kg; lead concentrations of 103.5 to 175.3 mg/kg in Area 3, with an overall score of 139.9; and lead concentrations of 145.8 to 165.7 mg/kg in Area 1, with an overall score of 140 mg/kg.

He said Area 1 was just completed and dredging has just started in Area 2, which is the section of Mill River stretching from the railroad tracks south to the Post Road and the section closest to the former site of the Exide battery plant. After that, Area 4, which is on the south side of the Tide Mill Dam, will be dredged.

“The plan is to be complete with Area 4 dredging by late October,” Culp said. Then, verification samples of river water will be taken and TRC will send a report to DEEP saying it’s met all the requirements of the cleanup plan. Once DEEP agrees, which is anticipated by next spring, the dredged sediment will be carted to landfills and equipment will be removed from the site, Culp said.

“I’m anticipating it’s going to be sometime late next summer when we’re going to have all our equipment offsite and all our guys scattered to the winds,” Culp said.

TRC has been looking into bringing the dredged sediment to landfills in Massachusetts, Pennsylvania and Connecticut, but Culp said a landfill hasn’t been chosen because the exact volume of sediment and when it will leave the Exide property aren’t known yet.

Sediment from Area 2, the section of Mill River closest to the former factory, is being stored in separate geo-textile tubes and will be tested to determine if it’s hazardous. If it is, that sediment will go to Clean Earth in New Jersey for treatment, Culp said.

“Everything we’re dredging from the river is leaving the site,” Culp said.

Yellow buoys that passing motorists may have noticed in the river represent “turbidity curtains” that surround an area being dredged, Culp said. He said dredged sediment is pumped to large geo-textile tubes on the Exide property. Water is then pumped into a treatment system to be cleaned before it’s returned to the river, while the sediment stays enclosed in geo-textile tubes on the property. Culp said the temperature of water is tested before it’s returned to the river so it doesn’t create thermal plumes and that workers monitor air around the geo-textile tubes and stormwater runoff from the site as well.

“To date, all the remediation has been performing to requirements,” Culp told the selectmen. “As far as remediation projects go, it’s been fairly straightforward.”

Exide closed its battery plant in 1981 and its factory sat vacant for about 25 years before it was demolished in 2005 and lead-contaminated soil was removed from the Post Road land. The cleanup of Mill River is the final part of the remediation

Once the site is fully cleaned, the 6.25-acre property — the second-largest vacant commercial property in town — can be developed and added back onto the tax rolls.

First Selectman Michael Tetreau said the cleanup is being funded entirely by Exide Group Inc. “There’s no cost to the town,” he said.

Tetreau said the river cleanup was under the purview of DEEP but the town’s Conservation Commission, Shellfish Commission and Harbor Management Commission, along with Fairfielders Protecting Land and Neighborhoods, a citizen’s group, “all have continued to be involved.”

“It’s really DEEP and Exide that’s doing it formally, but they’ve been very open in keeping everyone involved,” Tetreau said.

Selectman Kevin Kiley asked Culp to arrange a tour of the cleanup for the three-member Board of Selectmen, and Culp said he could do that.