The Cromwell community is one step closer to complying with the Otago Regional Council's wastewater rules after its community board this week signed off a draft resource consent application, a step in upgrading the treatment system.
''We're not open to letting ourselves be told off again,'' board chairman Neil Gillespie said.
Early last year the board received a slap on the wrist from the regional council and was told it had two years to come up with an acceptable long-term wastewater management solution.
In considering the draft application, the board was asked to make a decision on what would trigger an upgrade of the system - a time period or amount of nutrient growth.
Central Otago District Council water services manager Russell Bond said both options had pros and cons as locking in upgrades to a time frame could lead to work being done before it was necessary but using nutrient levels as a trigger could mean an upgrade earlier than planned.
However, that was stage two of the wastewater system upgrade and the application was for stage one, which was mainly focused on ''bug counts'' in the water, he said.
''It's [the need for upgrade] very much at the end of the 35-year period we're looking at.''
Consent is being sought to discharge treated wastewater to Lake Dunstan, contaminants to air and sludge or biosolids to land for a 35-year period.
Consent is also being sought to discharge treated water to Lake Dunstan and contaminants to air from the Bannockburn plant for six years, before that plant is decommissioned.
The board agreed the application should contain the five-year, $14 million construction time frame, as set out in the district council's long-term plan, and that stage two, the upgrade trigger, should follow ''if and when required''.
''We need to recognise that stage two needs to happen, but that we don't know when. Council needs some certainty about what to budget for but, at the same time, we don't want to spend money if we don't have to.
''The consent is about what comes out of the pipe, not how we will do it,'' Mr Gillespie said.
A date will be earmarked for ''financial security''.
Treated wastewater from the Cromwell plant is discharged from oxidation ponds to the Kawarau arm of Lake Dunstan through an outfall pipe.
The application seeks consent to discharge up to 7500cu m a day.
It also includes an outline of how the Bannockburn wastewater pond will be decommissioned. The consent for that pond is set to expire on December 21 this year and wastewater from that system will be incorporated into the Cromwell system.
Last December, after public consultation, the board decided to seek resource consent from the regional council for a staged system, the cheapest of the two options it had short-listed.
It had asked district council staff to prepare a resource consent application that would initially meet public health objectives and with later stages to meet nutrient objectives over an agreed time.
The chosen option resolves the public health ''bugs in the lake'' issue by 2016.
