Cheshire East Council has admitted the cost of an investigation into the Lyme Green project, near Macclesfield, came in at £225,000.
The council sought expert legal advice regarding the actions of senior staff at the council after contractors began construction of the waste facility without planning permission.
Public sector lawyer Malcolm Illey was appointed as a designated independent person to carry out the investigation. EU procurement rules were also broken during the contracting process.
The cancelled contracts and internal investigations have cost the council £800,000 in total.
Cllr Michael Jones, Chesire East Council leader, said: "In setting up this independent investigation, we wanted to ensure that there was a full and robust account of what had actually taken place in relation to Lyme Green.
"We knew in advance that the use of a designated independent person would not be a cheap option but, given the level of public concern about the matter, we felt this was a necessary price to pay.
"We have worked closely with the DIP, which has enabled the time taken to complete the review to be shortened, as well as giving us very clear outcomes in his comprehensive report. Actions have been taken or are in hand on all these recommendations.
"We have also engaged the services of an expert legal adviser to assist this process, particularly in supporting the work of our staffing sub-committee, which considered the report of the DIP. The full costs of all this vital work have now been identified as £225,000."
The council has promised it will shortly issue a summary of Illey's findings, whose report must remain confidential.
Last month, the finance director of Cheshire East Council left her post along with several other senior members.