ORONO, Maine — The Maine Public Utilities Commission has granted a fifth extension to allow a Casella Waste Systems Inc. subsidiary and Bangor Gas Co. LLC to resolve a dispute over a proposed seven-mile methane gas pipeline between the Juniper Ridge landfill in Old Town and the University of Maine.

Talks began in late April after Bangor Gas claimed the pipeline deal between EcoGas LLC would hurt its ratepayers and lead to the “degradation of our franchise,” an attorney for Bangor Gas said during an initial case conference with the PUC on April 25.

On Monday, the groups requested their fifth extension, which was granted by the PUC the next day. EcoGas and Bangor Gas representatives have been asked to report back on Oct. 1 and update the commission on the progress of negotiations.

Don Meagher, Casella’s manager of planning and development, said Wednesday that talks are moving forward. Otherwise, he said, discussions would have ended and the matter would have been decided by litigation.

According to PUC rules, there is no statutory deadline for this type of case.

Meagher said that at this point he doesn’t know whether the lengthy discussion process will delay EcoGas’ plans to have UMaine hooked up for methane service by the heating season of 2013.

“Our focus right now is the PUC filing,” he said. “Once we get to whatever resolution we arrive at, and whenever we arrive at it, we’ll evaluate the schedule at that point.”

Meagher said the agreement with UMaine could be altered if the schedule can’t be met.

The EcoGas-proposed pipeline system would move methane gas from Casella-operated Juniper Ridge Landfill in Old Town to UMaine’s Steam Plant, where the gas would be used to run boilers and create heat for campus buildings.

Made of 12-inch-diameter, high-density polyethylene pipe, the gas pipeline would run south to Route 43 before turning east on Route 43 to the intersection with College Avenue Extension, where it would continue on to the Steam Plant. Casella expects the project will cost between $11 million and $13.5 million to design, build and permit.

The university and Casella reached a deal in November 2011 after about three years of discussions.

UMaine has said it expects to save $15 million under the 20-year agreement, while reducing its carbon footprint.

Bangor Gas has said that the pipeline deal would lead to degradation of its franchise.

Bangor Gas provides gas service to communities in Greater Bangor, including the University of Maine, and “is and will be directly, substantially and adversely affected by the petition of EcoGas LLC,” according to the company’s petition to intervene in PUC proceedings.

The Bangor Gas petition argued that the pipeline proposal is “unlawful, unfair and will result in harm to [Bangor Gas] and its customers.”