Campaigners say the smell from the sewage works is still causing problems.
But Rob Kirkwood said he expected a monitoring report due to be published next week will refuse to give a clear judgement on the latest efforts to deal with the smell.
“They are going to fudge the issue,” he said.
“There were five odour abatement plans to choose from and the council chose option A. They have been monitoring it for the past year and they are supposed to pass it or fail it, but they are going to do neither. They are going to say there have to be some improvements and let Scottish Water off the hook.”
Work began on the £20 million package of measures in 2008. They included fitting an “odour abatement plant” above the sewage tanks to filter out noxious smells, new screening and treatment equipment at the sewer entrance and covering the open channels between the different areas of the plant.
During the monitoring period, which ran from June 1, 2011 and August 31 this year, environment officials carried out 750 assessment visits to the site, detecting sewage odours on 89 occasions.
Mr Kirkwood said the council was required to judge the smell against set criteria – unpleasantness, intensity, frequency, duration and its impact on people’s ability to enjoy local amenities, such as their gardens.
“The smells have been frequent, but the council focussed mostly on intensity, the most subjective of the criteria.”
Mr Kirkwood said if the council were to rule option A had failed, there would be an obligation on Scottish Water to carry out further measures under option B.
But he said: “We have always argued only option E will work because that’s the one that covers the tanks.”
City council environment convener Lesley Hinds said a draft report had been prepared and she was meeting residents on Monday to discuss it.
“The smell has improved, but not to a level which is acceptable,” she said.
A Scottish Water spokesman said: “We have been working closely with the council on this matter and await publication of the report.”