Lake Rotorua treated wastewater discharge: Environmental effects study

Abstract

Rotorua Lakes Council is undertaking a decision-making process to resolve how treated municipal wastewater from the city of Rotorua (Bay of Plenty) should be discharged after 2019, when irrigation operations at the Land Treatment System (LTS) in the Whakarewarewa Forest are scheduled to cease. Six main options for enhanced wastewater treatment were assessed in this study, which include several additional sub-options. The options involve varying grades of treatment to enhance the removal of nutrients from the wastewater relative to current treatment performance. Seven potential discharge sites to water have been identified in three areas: in the lower reach of the Puarenga Stream; on the lake shoreline near Sulphur Bay, and; offshore on the lake bed, 2 km to the north of the Puarenga Stream mouth.