WILTON — After exploring four options for Wilton’s Sewerage Plant, engineers from Olver Associates of Winterport have recommended upgrading the 31-year-old facility.

Selectmen want to share the plans with sewer users, who will be looking at higher rates over the next three years. Two public hearings are tentatively set for 6:30 p.m. April 20 and May 4 at the town office, Town Manager Rhonda Irish said.

Other options reviewed included building a new plant, looking at a different system such a lagoon plant or pumping to another municipality such as Farmington, she said.

Upgrading the plant is usually cheaper than starting from scratch, Bill Olver had previously told the board. He thought the plant had a lot of potential to be renovated for another 40 years.

Olver recently met with selectmen to explain the findings and discuss financing the project. Initially looking at more than a $10 million project, the engineers are stilling working to bring that figure down to $8 million or $9 million, Irish said.

The potential for getting a Rural Development loan/grant through the U.S. Department of Agriculture is being pursued. Irish expects that to be 55 percent loan and 45 percent grant. The final cost figures haven’t been determined yet but will include renovation of the town’s 31 pump stations as part of the sewerage plant project.

Customers have not seen an increase in their bills in more than 20 years. Based on water usage, a household of four is currently paying about $270 per year. Increases made in increments over the next three years will bring that figure up over $500, she said.

The plant has exceeded its initial life expectancy of 20 years.

“If we don’t replace it within the next three years, we will have to in four or five years when there may not be the opportunities for grants,” she said.

The engineers expect to complete their design by 2011 and put the project out to bid by December 2011. Completion of the project is expected in December of 2013.

There must be public hearings and approval of the project at a town meeting to continue.

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