WILTON — Residents at a special town meeting Tuesday night voted to accept a $2.75 million federal loan that will be used to upgrade the town’s sewer treatment system. The money will be used to overhaul the waste treatment facility, which hasn’t received any significant upgrades since its construction about 40 years ago.

“With waste water plants, there is usually an inferred 20-year use of life before you need an upgrade. So it’s not unusual every 20 years to have to invest in your infrastructure,” said Bill Olver, of Olver Associates, the engineering firm that compiled the overhaul plan. “This is a complex (plant), and it is now at almost twice its use of life. … Wilton has gotten every inch of life out of the plant.”

The $2.75 million U.S. Department of Agriculture loan, along with a $1.35 million grant attached to it, will be used to complete an upgrade to the waste water treatment plant on Davis Court. Residents voted 12-4 to approve accepting the money at the sparsely attended meeting in the Academy Hill School cafeteria.

The $4.1 million will be used to complete Phase Two, the final phase of the $10.86 million project, which has been in the works since 2009. A 2.875 percent interest rate is attached to the loan, which has a 29-year repayment term.

Debt payments on the loan will cause sewer user rates to increase $340 from $420 per year to $760 per year. The rate increase is expected to be implemented in July 2016. It was also noted at the meeting that this increase does not reflect any other increase that might be needed to offset maintenance or utilities costs that might arise.

“This is a very minimal upgrade. I know it doesn’t sound that way at 10 million (dollars),” Olver said, “but we’ve cut a lot of things out of the project to make it as lean as it could be.”

Wilton’s waste treatment plant was built in 1978 and has not received any major upgrades since its construction. Olver said the town has done a great job keeping rates low and getting its money’s worth out of the existing plant, but the plant cannot go any further without significant upgrades to the waste treatment system. Improvements also will be made to the building housing the plant itself in order to bring it up to code, Olver said.

The Phase Two upgrades will include installingvtwo new screw pumps that lift wastewater into the plant, replacing the current inoperable grit removal system, replacing the fine-screen filter system and upgrading the biological treatment process used at the plant to meet modern standards. Phase One included maintenance and upgrades made to the 26 miles of sewer piping and 31 pump houses in Wilton, which serve the system’s 944 customers.

Lauren Abbate — 861-9252

labbate@centralmaine.com

Twitter: @Lauren_M_Abbate