Filterra Approved by Auckland Council. Rate of 4450mm/hr

The Filterra Approval is a real game changer for stormwater treatment in New Zealand. It means biofiltration can be installed on suitable sites at a similar size to underground cartridge filters.

Auckland Council’s decision was based on the updated approval for enhanced removal from the Washington Department of Ecology USA.

For enhanced approval an innovative treatment device must demonstrate the following performance at the infiltration rate approved:

  • Greater than 80% TSS removal of influent concentrations great than 100mg/l and
  • Greater than 30% removal of dissolved copper for influent concentration range of 0.005 mg/L to 0.02 mg/L, and
  • Greater than 60% removal of dissolved zinc for influent concentration range of 0.02 mg/L to 0.30 mg/L

“We always knew the device could achieve the performance requirements at higher flow rates as we had seen it in the laboratory.  It just took time for the research team at Contech Engineered Solutions to capture enough storms to perform the required statistical analysis’,’  says Mike Hannah, Technical Director, Stormwater360


Conventional raingardens have a infiltration rate of 100 – 1000 mm/hr.  With its higher flowrate, the Filterra reduces the required footprint of a raingarden and has much lower capital and operational costs.




For more information on the Filterra or the approval, please contact: [email protected]