Watercare Services Limited engaged GHD as their technical
adviser for the provision of a public collection network and
wastewater treatment system for the small coastal community of
Kawakawa Bay (Auckland, New Zealand).
Situated south-east of Auckland, Kawakawa Bay
had experienced a high failure rate of the local on-site wastewater
systems. The recommended option was a vacuum operated collection
system followed by a Membrane Bio Reactor (MBR) treatment process.
The treatment plant consists of inlet works, process tanks, and the
membrane separation system. A seasonal lagoon balances the influent
flow, and a treated water operational lagoon stores and balances
flows for effluent disposed using rotating sprinklers in the nearby
forest. The wastewater scheme was commissioned 2011. Public health
issues have been reduced, and the quality of the surrounding marine
environment has improved through the reduction in effluent
contamination of the receiving areas.