New Plymouth Wastewater Treatment Plant (WWTP) was commissioned in 1984 and had a liquid stream comprising three milliscreens, grit removal, two Carrousel activated sludge tanks, two secondary clarifiers and chlorine disinfection prior to discharge via an ocean outfall. A third secondary clarifier was subsequently constructed in 2007.
To mitigate the risk of the consent conditions changing after the upgrade was implemented, a decision was taken to renew the consent early to lock in the new conditions before undertaking the upgrade. New resource consents were sought which allowed NPDC to upgrade the plant progressively under project specific effluent quality conditions. As part of this consenting process, NPDC agreed to surrender its Waitara Outfall Consent. The 30 year consent was granted by Taranaki Regional Council in November 2011 and paved the way for Council to embark on the upgrade.