Work to make Hāwea’s wastewater treatment plant (HWTP) compliant by improving the quality of the treated effluent and increasing its capacity to meet demand is progressing well with a completion date expected in August this year.

The $3.2M project is financed by central government’s Three Waters stimulus funding and coordinated by the Queenstown Lakes District Council (QLDC).

The upgrade to the existing plant will incorporate Moving Bed Biofilm Reactor (MBBR) technology which provides essential micro-organisms for treating the wastewater, with a floating plastic platform to grow on. 

According to the council this proven technology not only provides higher treatment capacities but also is well suited to cold temperatures and constrained sites. 

The project also upgrades the existing effluent disposal field to optimise its efficiency 

This project, however, is only an “interim solution” designed as a stop-gap measure to provide short-term relief for Hāwea’s wastewater woes while giving the council about five years to achieve its preferred long-term plan to connect Hāwea’s wastewater to the Upper Clutha’s central wastewater plant Project Pure.

Hāwea’s wastewater woes

Hāwea’s existing wastewater treatment plant was built in 1998 and upgraded in 2000; but it doesn’t meet current demand, has very limited capacity to meet the future demand already indicated in residential subdivisions, such as Longview, and has been in breach of compliance conditions for the past six years.

With increasing concerns about the non-compliant wastewater plant and other infrastructure needs, the Hāwea Community Association established an infrastructure subcommittee.

The subcommittee’s chair John Langley told the Wānaka App that, given the plant had been non-compliant for years, “the upgrade to the existing plant should have happened a lot earlier”.

Connecting Hāwea’s wastewater to the district’s primary treatment plant, Project Pure, near the Wānaka airport is the council's preferred long-term solution. PHOTO: Supplied

While the council investigated long-term solutions, including piping directly to Project Pure, the community association was provided very little information which led John to suspect the business case did not stack up.

“To add further to my concerns we were provided with timelines for the proposal which…were hopelessly unrealistic. Subsequently this [long-term solution] was put to one side and a more thorough process adopted.

“But significant time was lost,” he said.

Wānaka Community Board chair Barry Bruce recently updated the board members on the progress of this interim project, noting that while the upgrade was expected to achieve compliance it would not provide for additional demand on the network associated with the expected growth in the number of dwellings in Hāwea.

“My understanding is that if the upgrade can’t meet demand then developers will need to either pay for [wastewater] to be trucked [away or] put in holding tanks and discharge [the wastewater] when demand on the treatment plant is low,” John said.

However, contrary to the WCB chair’s report, QLDC media spokesperson Sam White said the interim upgrade is designed to fully utilise the existing discharge consent which includes the peak-day flows during the busy summer season and “will allow for the projected growth within Lake Hāwea”.

The long-term solution

While the interim upgrade will provide greater capacity, a long-term solution is needed to future-proof the plant and provide an option to connect Hāwea Flat and Hāwea campground to the scheme. 

The council’s preferred long-term solution would pipe the wastewater from the existing Domain Road pump station, south along an unformed legal road to Camphill Road; thereafter it’s piped through council road reserve and beside state highway 6, crossing the Hāwea and Clutha Rivers in pipes attached to the existing bridges, to the No2 Albert Town Pump Station where it connects to Project Pure. 

Although it’s not a direct route to Project Pure, this plan doesn’t cross private land.

This option was one of five shortlisted and considered by council; the other options included building a new Hāwea wastewater plant (in the same way Cardrona has its own treatment plant); and using the existing network to connect across private land directly to Project Pure.

While the council has been working on this preferred option it’s far from certain, John said. 

The HCA has been advised the preferred solution will not be confirmed until the supporting business case is completed and approved; meanwhile further investigation may result in an alternative option being recommended.

Last month the community was invited to submit feedback on this preferred long-term solution. The feedback is currently being reviewed and summarised.