Apex Water was engaged to upgrade the Hawea wastewater treatment plant, which consisted of a single oxidation pond followed by an irrigation area and disposal trench, and improve overall performance, specifically the levels of ammoniacal-nitrogen in the discharge.The heart of the upgrade was installation of a sidestream moving bed bio reactor (MBBR) to nitrify the wastewater before returning it to the inlet of the pond.  The upgrade also included the installation of a feed pump station and inlet screen, installation of baffle curtains in the pond to optimise the flow path, installation of Apex disk aerators on the pond for increased aeration capacity, and “winterisation” of the irrigation area to increase its use.  Site enabling works and electrical upgrades were also completed.Ongoing operational support has been provided to Council and their operators since the project was completed.