Antrim Township Municipal Authority members are sharpening their scissors after receiving a new estimate from engineers for a planned expansion of the township’s wastewater-treatment plant.

A $7.8 million estimate made nearly a year ago for the cost of the work needed on the 40-year-old sewer plant has grown to $10 million, according to a presentation made last week by engineers with GHD of Harrisburg at an authority meeting.

“It’s about $2 million more,” authority Chairman Mike Smith said. “We have to figure out a way to cut some of it out. Based on the presentation, I think we can trim some of that down. It exponentially went up, more than we thought.”

Built in 1978, the plant underwent major modifications in 1998 that now have exceeded the 20-year life expectancy. There also was an upgrade in 2015.

Officials have said the plant is holding its own in meeting state standards, but an upgrade is necessary. A 1999 UV system there recently was upgraded at a cost of $1.3 million.

The current upgrade proposal includes a new generator, electrical building, blower facility, headworks facility and two additional sewage batch reactors for an estimated construction cost of $8.66 million.

GHD design, permitting and bid services are estimated at $425,850.

The estimate for contract administration and on-site project representation is $606,500. That item, along with the blower work, rock excavation and concrete testing, threw up red flags for authority members.

“I think they’ve overstated the rock work,” Smith said. “There are a few things like that that we see already. We need to see details. They should give us a line chart that should distinguish each area as to why (the estimate) went up that much.”

GHD is anticipating advertising for bids in mid-March, so final design would need to be completed before then.

The project is expected to take two years to complete.