HALLOWELL, Maine — Bangor Gas Co. believes a seven-mile pipeline that would bring methane gas from Juniper Ridge Landfill to the University of Maine in Orono would hurt its ratepayers and lead to the “degradation of our franchise,” a company attorney said Wednesday.

EcoGas LLC, a subsidiary of Casella Waste Systems Inc., will sit down with representatives of Bangor Gas to hash out disagreements over the proposed pipeline.

During an initial case conference with the Maine Public Utilities Commission on Wednesday, Bangor Gas was one of six entities to file a petition to intervene as parties during the PUC’s consideration of the project.

The 12-inch-diameter, high-density polyethylene pipeline system would move methane gas from the Old Town landfill to UMaine’s Steam Plant, where it would be used to run boilers and create energy and heat for campus buildings.

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.

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

Bangor Gas attorney Alan Stone said the pipeline would hurt the company’s ratepayers and the company as a whole. He asked the PUC to be slow and cautious in considering the EcoGas proposal.

Stone also questioned the long-term integrity of pipelines that carry landfill methane gas.

“It’s new, it’s interesting, it raises challenging issues,” Stone said.

Jeffrey Thaler of the University of Maine School of Law said the campus has been careful in developing the plan during several years of work with Casella.

“The university has done its research,” Thayer said during the meeting. “This is not such a novel enterprise, especially for state universities.”

The University of New Hampshire has a similar agreement that brings landfill gas from a New Hampshire landfill to supply the campus with fuel, he said.

As of now, methane gas produced by decomposition in the landfill is burned off. Casella and UMaine representatives have called that a waste, arguing that a pipeline would allow the university to benefit from the energy the landfill produces.

Carol MacLennan, the PUC staff attorney who moderated the meeting, advised Bangor Gas and EcoGas representatives to sit down to discuss the concerns associated with the project and come back to the PUC with a report on May 21.

The city of Old Town; UMaine; Maine Natural Gas, another natural gas supplier; Paul Schroeder of Orono, representing a group of residents concerned with Maine waste management policies and the operation of Casella; and the Maine Public Advocate Office, which represents Maine utility consumers in any matter that is under the authority of the PUC, also filed intervention petitions.

The petitions mostly argued that the entities have a vested interest in the PUC proceedings and that representatives of those groups wanted to be involved and up to date on discussions related to the project.

The gas pipeline would run south to Route 43 before turning east on Route 43 to the intersection with the 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 discussion.

Casella hopes to complete the permitting process for the project by Dec. 31 so it can begin construction by March 2013, according to the petition. The pipeline could be ready to send gas to UMaine by the winter of 2013-14.