That would include reviewing or rescinding earlier council resolutions.
He said other matters that any such meeting would need to consider included the content of mayor Annette Main's statement in the Chronicle acknowledging that, at the time, councillors were not made aware of concerns about the original design nor kept in the picture about everything that was happening at the plant.
"The reason this occurred needs explanation. That won't be easy as those involved at the time are no longer involved," she said.
Mr Adams said the council also needed to consider claims by major industries that they would not use the new plant or accept the costs incurred, which they said were in excess of comparable costs to discharge into other treatment plants.
Then there was the matter of financial risk if charges relating to new plant could not meet the scheme costs if those industries were not involved. He said under the Act there was "potential personal risk" for the councillors themselves.
Mr Adams said more telling was advice from an "independent expert" who had been retained by local industries and who had presented an alternative scheme to the council's executive on June 10. That advice was that a compliant and sufficient scheme could be installed sooner, at substantially less cost, and which would operate within the resource consents.
Following Chronicle inquiries, councillor Charlie Anderson said he would support the Ratepayers' Association request. "I would like the whole thing put on hold until after the election," he said.
Councillor Philippa Baker-Hogan said she would not support the call for an extraordinary meeting because she was sure it did not comply with standing orders and would be rejected anyway.
However, she supported the intent of the request.