AUGUSTA, Maine — The Maine Board of Environmental Protection on Thursday denied an Old Town resident’s attempt to halt or stall the proposed expansion of Juniper Ridge Landfill.

During the board’s meeting, Old Town resident Ed Spencer made his case in opposition to the Department of Environmental Protection’s public benefit determination from earlier this year that favored a 9.35 million cubic yard expansion of the state-owned landfill. Casella Waste Systems Inc., which operates Juniper Ridge, originally sought an expansion more than twice that size — 21.9 million cubic yards.

“I’m disappointed, of course. I think it’s an unfortunate decision,” Spencer said after the board unanimously voted to deny his appeal. “I just don’t see the justification for this large of an expansion.”

Spencer has said he agrees with many of the findings in the DEP’s public benefit determination but contends that the state doesn’t need that much increased capacity in the next 10 years.

Spencer argued that a number of factors — including a depressed economy that could keep down the amount of construction and demolition debris going into the landfill, the potential for opening up capacity at the Crossroads landfill in Norridgewock and the Dolby landfill in East Millinocket, and the fact that the DEP denied a similar Juniper Ridge expansion request in 2010 — show that the state doesn’t need that much increased capacity at Juniper Ridge to suit the state’s needs for the next decade.

Board members, including Elizabeth Ehrenfeld and M. Wing Goodale, expressed concerns when they learned during presentations by Spencer and Casella representatives that a significant portion of the waste going into the landfill originated out of state.

Only in-state waste is allowed in Juniper Ridge Landfill, but state statute defines in-state waste as any waste that is “processed” at a Maine facility. That processing includes sorting and incineration of waste.

The board ultimately decided that questions about state statutes and regulations were separate issues from the public benefit determination it was examining Thursday.

Landfill opponents have called for an independent, third-party audit of what goes into Juniper Ridge and where it comes from, but Casella representatives contend that their books are open and show the company is following the rules and regulations that have been laid out in statutes and contracts.

The board agreed in May to hear Spencer’s appeal. BEP Chairwoman Sue Lessard said at the time that Spencer had standing to appeal because he was an “aggrieved person,” largely because he lives less than two miles from the landfill. She agreed with his claims that his property and quality of life might be affected by odors, noise and traffic coming from Juniper Ridge.

Lessard rejected similar appeals from two other landfill opponents, Charles Leithiser of Old Town and Sam Hunting of Orono, in large part because they live farther away from the landfill.

Now that Spencer’s appeal has been rejected, Casella and the State Planning Office may file an expansion application to begin the licensing and permitting process.

Tom Doyle, an attorney for Casella, told the board that Juniper Ridge will run out of space by 2017 or 2018 and the licensing and permitting process for an expansion is likely to take five or six years.

“All the public benefit determination does is get an applicant to the starting line,” Doyle said.

Juniper Ridge takes in more than 700,000 tons of solid waste per year, Doyle said. If the expansion had been delayed by the overturning of the DEP’s determination of public benefit, the state might have found itself in a “waste disposal crisis,” he argued.

Doyle said Spencer’s arguments for why an expansion wasn’t needed relied on the assumption that a “perfect storm” of uncertain circumstances would occur, including the opening of other landfills to more waste — which would involve lengthy, difficult licensing and permitting processes similar to what Casella is about to start.

He argued the determination of public benefit shouldn’t be trumped by “a bet.”

Doyle called DEP Commissioner Patricia Aho’s finding of public benefit for an expansion “well reasoned, prudent, and entirely consistent with her statutory charge,” despite the fact that Casella got half the capacity it wanted.

Juniper Ridge is likely to see even more waste in the near future after the Biddeford City Council voted 8-1 on Tuesday to close the Maine Energy Recovery Co. trash-to-energy incinerator by next year.

Casella representatives have said they still have customers to serve and that waste that would have gone to MERC will now have to go to Juniper Ridge for disposal.

MERC General Manager Ken Robbins said in April that his facility expects to process 260,000 tons of waste this year and that the majority of that trash originates outside of Maine.

In another meeting in Augusta on Thursday, the Legislature’s Government Oversight Committee was scheduled to consider whether to take action on a request for an investigation into Casella and its business dealings with the state.

The request for an investigation has been up for discussion at four separate meetings, but the issue was tabled again because the committee was short on time on Thursday. Discussion about the potential for an investigation will appear on the agenda for the Aug. 14 meeting.