The Bluff Wastewater Treatment Plant, in McGorlick St, was built in 2000 to treat residential and industrial wastewater from the Bluff township.
The existing treated wastewater discharge is to the coastal and marine area, which operates under an Environment Southland-issued 25-year resource consent that will expire next year.
Invercargill City Council infrastructure group manager Erin Moogan said now was the time to be preparing, investigating and having discussions around the best possible option for treating and disposing of Bluff’s wastewater, ahead of lodging the resource consent application early next year.
"We are working closely with Te Ao Mārama, the Southern District Health Board and stakeholders on an evaluation process to identify the best practicable option to manage Bluff’s wastewater in the future," she said.
"The council needs to follow a process to consider options and we’re taking this time to ensure that we’re considering all possible options to ensure we get the best outcome for the community."
All wastewater from Bluff is treated through a wastewater screening process, then via an aerated lagoon, then processed through both clarification and UV disinfection before it is discharged into Foveaux Strait via a 50m outflow pipe.
"As part of this process we have considered a range of criteria including cultural values, financial implications, public health protection, available and existing technology and the impact on the community," Ms Moogan said.
"From these criteria we have shortlisted four options and we are now working through our final investigations and detailed assessments for each option."
Under the proposed new options, the treatment of wastewater would remain the same, but the way in which it was discharged and the location of the discharge could change.
The shortlisted options are: add a new wetland phase; add a new land contact phase; apply to land, with existing discharge as backup and apply fully to land.
When a more detailed evaluation of each of the four options is complete, it is set to be presented to council’s infrastructure and projects committee in October.
