FAIRFIELD — Most residents probably don’t give the town’s sewage treatment plant much thought, but it will become a focal point in the coming years as $62.5 million in upgrade plans are underway.

A facilities plan has been completed for the plant on Richard White Way, according to Public Works Director Joseph Michelangelo, and is awaiting state Department of Energy and Environmental Protection approval.

“This is our roadmap going forward, but those are not design plans for construction, by any means,” Michelangelo said. “To begin the design and subsequent construction of the plant upgrade, a capital appropriation must be requested and approved.” He said that request will probably be made later this year.

The plant, which runs constantly, is unmanned for two-thirds of the day, Michelangelo said, making reliability an important consideration. Some parts of the plant are almost 70 years old, according to a brochure put together by the Water Pollution Control Authority that summarizes the facilities plan, with the help of a state grant.

“Although there is some automation and alarms,” he said, “the plant is largely on cruise control for most of the time.”

Rather than wait for something to fail before it is replaced, Michelangelo said the town wants to have a planned replacement before that happens.

Proposed in the facilities plan is larger, more-efficient equipment, so the plant can handle current and future flows, rehabilitation of the settling tanks, new odor control for solids handling, new influent screening, grit removal, and pumping systems, upgrade other odor control systems, and provide additional odor control.

“Keep in mind that when construction work is performed for an upgrade, we still need to accept flows and treat waste,” Michelangelo said. “Because of this, we don’t want to be in a continuous construction mode. We want to address all of the items in one construction project, and limit the disruption as much as possible, hopefully under two years.”

First Selectman Mike Tetreau said a placeholder for bonding for the sewer project has been included in the town’s “waterfall” chart, which tracks current and future bonding projects. “I don’t think this will be able to start for a few years yet,” Tetreau said. “This is going to need major planning.”

Tetreau and Michelangelo said funding in Connecticut for such large sewer projects has been available via the Clean Water Fund, and Tetreau said the town’s share would be bonded over 20 years. “Part of the evaluation is whether it makes sense for the WPCA to do the bonding, and look to sewer use fees to help fund, or whether it should be financed through general bonding for the town.”

Michelangelo said historically, the Clean Water Funds have been about 20 percent of the costs. “As these are federal funds from the EPA passed through the state DEEP, I would not expect the state financial condition to be a factor, but one never knows,” he said.

A recent increase in sewer use rates was not done, Michelangelo said, with an eye toward funding the upgrades. “In addition to the normal operating budget expenses, the WPCA is funding portions of the hardening project, facilities plan, a new generator at the plant, a new generator at the Mill River pump station, and a replacement of the east trunk line in the area of Grasmere/Ash/Kennard,” he said. “The latest increase of the sewer user fee will ensure we maintain a fund balance before beginning an upgrade, but the current increase will not be able to fund a ‘down payment’ on the upgrade project.”

The sewer user rates went from $2.90 per cubic feet of water and a $70 minimum charge to the current $3.40 per CCF and a minimum charge of $125. Water usage during summer months is not used to calculate user fees.