"The confidentiality clause is extremely unpopular but that's the terms of the settlement our professional legal counsel could negotiate. We all wish this could be made public as there's no advantage to council for continuing confidentiality."
Mrs Craig said independent and expert advice determined the design of the original plant was extremely experimental and would never have worked.
She said the new plant was designed by the best in the world, peer reviewed by two independent experts and was similar to a proven design currently operating in Lower Hutt.
Urgency was needed because Horizons will not allow council to keep pumping raw sewage and industrial waste through the South Beach ocean outfall for any longer than three years, the window council had to build this new plant.
Mrs Craig said based on estimates of running costs in three years' time, the city's major industrial users can then estimate their disposal costs and determine the cost benefits to build more pre-treatment at their own sites.
"But until all that happens, no predetermination of final rates allocation could be made.
"No one wants to pay increased rates, so the longer the new plant build is delayed, is advantageous to them.
"However, raw sewage and industrial chemicals going out to our coast are a risk to our health from contaminated seafood and beaches.
"Let's stop the nonsense repeatedly visiting decisions and get on with growing jobs and population."