The incinerator in East Tullos – which can process 150,000 tonnes of waste every year, reducing the amount sent to landfill – opened in April 2024.
However it temporarily closed in June this year after original operator Indaver said it was reviewing its involvement due to “ongoing issues”.
Non-recyclable waste from the three councils was instead sent to landfill in Peterhead.
The incinerator re-opened in August, after the council reached an agreement with EfW Ness to run it.
EfW Ness told BBC Scotland News the facility was a “world-class project” that was reducing landfill for the region.
“After the operator abandoned the site in June, EFW took control, in collaboration with the council, to run the facility at full capacity,” a spokesperson said.
“Despite this, the council terminated the contract on 8 December, a decision which EfW considers wrongful and intends to contest.”
