BANGOR, Maine — The Bangor City Council is expected to decide Monday where to send its trash after 2018, a vote that could help shape the same decision in nearly 200 other Maine communities.

Councilors sat down with officials representing Penobscot Energy Recovery Corp. and the Municipal Review Committee on Tuesday night for one last round of questioning before the pivotal vote. The two groups have differing opinions on the most financially viable, effective and reliable way for the region to handle trash in the future — a hotly contested debate during the past year.

Most of the council’s questions about PERC focused on why its relationship broke down with MRC and why the Orrington-based waste-to-energy facility didn’t submit a formal plan to continue serving towns post-2018.

Councilor Ben Sprague expressed frustration at the “antagonistic relationship” that has evolved between MRC and PERC.

PERC officials said they made their intentions to continue operating clear early on and that they didn’t believe it necessary to submit an official proposal, as they already were partners with MRC.

MRC, a board representing 187 Maine municipalities that currently send trash to PERC, started seeking offers in 2011 from other groups to handle the trash load after the contract with PERC expires in 2018. It received 15 responses, including the favorite from Fiberight, which the MRC ultimately backed as the best option for its member communities.

Fiberight plans to build a solid waste recycling and biofuels processing facility located in the “triangle” area between Ammo Industrial Park, Interstate 95 and Coldbrook Road in Hampden.

PERC, however, wants to continue to operate, shrinking its staff and changing waste management practices to stay financially viable after 2018, when its energy contract with Emera expires.

One major hurdle PERC would have to overcome to win Bangor’s approval is a large difference in tipping fees, as Fiberight is quoting towns $20 per ton less than PERC.

Both sides have questioned whether the other can remain fiscally sound or serve the needs of communities. PERC officials say Fiberight’s new plant carries a higher risk because it uses technology not common to the United States, but Fiberight argues the model has been proven in Europe over the past three decades and will work here.

Fiberight and MRC say PERC’s equipment is outdated and that no similar facilities have been built since the 1990s, while PERC argues it’s proven technology that will be enhanced with new offerings. For example, PERC formed a partnership with Exeter Agri-Energy, a renewable energy company that converts animal and food waste into electricity and will take on organic waste.

Slowly, towns are beginning to decide which proposal to go with. So far, Brewer, Bar Harbor and Hampden are the only towns to make decisions. Each has gone with Fiberight and MRC. More communities are expected to take sides in coming weeks, and it’s likely many smaller communities could keep an eye to Bangor for determining which group to side with.

All MRC members are expected to choose a side by May 1, according to Bangor City Manager and MRC board member Cathy Conlow.

Follow Nick McCrea on Twitter at @nmccrea213.