HATFIELD — A $12 million upgrade to the town’s wastewater treatment plant is proceeding, but another $1.4 million is expected to be sought from town voters this spring to complete all aspects of the project.

The Select Board Tuesday voted unanimously to accept the lone proposal for the construction work, a $9.39 million bid from W.M. Schultz Construction Inc. of Ballston Spa, New York, following a recommendation from consultant David Prickett, president of DPC Engineering LLC of Longmeadow.

But the board’s vote comes with a request for Prickett to explore seeking additional loans from the U.S. Department of Agriculture to cover the costs of what are known as alternate parts of the project. Those $855,000 in alternates are not included in the bid.

A description of the project provided by the Select Board states that it will feature “a new headworks building with influent screening system and washer-compactor and grit removal system, replacement of secondary clarifier mechanisms, weirs and baffles (and) conversion of gaseous chlorine to liquid hypochlorite disinfection system.”

Upgrading the existing clarifiers and converting the existing gaseous chlorine to sodium hypochlorite, which is safer to use for the plant operators, though, can’t be covered under the amount originally appropriated via a Proposition 2½ debt-exclusion vote passed by voters in 2022.

Prickett said there was anticipated to be a small number of contractors who would submit bids, and it was a “roll of the dice.” “Bottom line is the dollar doesn’t stretch nearly as far as it did when this project budget was conceived five years ago, pre-COVID,” Prickett said.

The silver lining, though, Prickett said, is the town got a bid from a reputable company that has worked on similar projects in Great Barrington and Lenox and is fully qualified to work in Massachusetts.

To fund the project to its completion will require tough conversations prior to annual Town Meeting, though a plan to move forward is being developed in what Prickett calls a two-piece approach.

The first piece is to authorize the award for the base bid amount, which is within the project’s price tag, leaving a 5.1% contingency, or about $480,000. That is a “skinny amount,” he said, with his preference to usually have a 10-15% contingency.

The second piece is to find the funding for the three alternates. “We’d have to find between $1 and $1.4 million,” Prickett said.

Select Board Chairwoman Diana Szynal said this would likely mean asking for another override.

Following the original override, the town got a $2.4 million grant from the U.S. Department of Agriculture, coupled with a $9.5 million 40-year loan, for the upfront funds for the sewer plant improvements. The town has also adjusted sewer rates.

Prickett said a supplemental loan from USDA might be possible.

Szynal said the problem for the town in estimating how much such a project will cost is the length of time it takes to get from design to construction.

Scott Merzbach can be reached at smerzbach@gazettenet.com.