Whangarei District Council has awarded the contract for an upgrade of the Hatea Pump Station to United Civil Construction Ltd for just over $4 million.
Updated:
9/03/2011 11:13 a.m.
The Hatea Pump Station in Whareora Road, which serves about 2,300 houses, was identified as the next most significant point for sewage overflows during extreme wet weather, after the Okara Pump Station. When excessive amounts of rainwater enter the sewerage system, wastewater overflows from the pump station into the Hatea River. The risk of overflows from Okara has been significantly reduced following the installation of a second rising main from the Okara Pump Station to the Kioreroa Road Wastewater Treatment Plant and the installation of new pumping equipment, so Council staff have turned their attention to the Hatea Pump Station.
The new contract is for the construction of a 1000m3 storage chamber and treatment process adjacent to Whareora Road and beside the existing sewer pump station. The work includes the construction of a new sewer pump station to replace the existing station as well as the storage tank and treatment facility. Council recently purchased the land where the tank is to be constructed.
Infrastructure & Services Committee Chair Greg Martin says the construction of the tank and treatment facility will significantly decrease the extent of overflows from the sewer network during wet weather. “This is very good news for the immediate environment - the Hatea River - and for our harbour. Storm flows will be able to be diverted into storage either for treatment and discharge, or to be pumped to the wastewater treatment plant when the sewer network has sufficient capacity,” he said.
“It will also provide greater than fifteen hours’ storage in the event of equipment or power failure. The existing station has approximately twenty minutes’ storage.”
The proposed storage tank includes screens and a settlement tank, with the option of chemical addition to assist settlement. If the volume of storage required exceeds 1,000 m3 the settled effluent will be pumped through an ultraviolet light disinfection system treatment system before being discharged to the Hatea River via a rock infiltration bed.
The upgrade work is part of a longer term wastewater strategy. Council adopted Stage 1 of the strategy in July 2010, which involves a number of capital projects to improve the level of service provided by the city wastewater system, upgrade the sewerage system and mitigate the effects of stormwater infiltration to the sewerage system.
The Stage 1 programme included the installation of a storage facility at Hatea in 2010-2012 with a budget of $2.25 million. A treatment process was to be constructed in 2013-2014 as part of Stage 2 of the wastewater strategy, with a budget of $2.15 million. Once design work began, it became apparent that the treatment process could be incorporated effectively with the storage tank. There was also strong Council and community support for the treatment process to be brought forward and constructed as part of the storage tank. A storage and treatment facility was subsequently designed and Council sought registration of interest to build it via a public tender in November 2010. From this, three preferred suppliers were established. Tenders were sought from the three preferred suppliers in December. Councillors approved the awarding of the contract to United Civil Construction at the Infrastructure and Services meeting today (9 March 2011) at 9 am.
Council also approved a proposal to purchase a number of proprietary components outside the construction contract to minimise the project timeframe and allow savings. These include valves, flow meters, UV reactors, screen, pumps and a transformer at an estimated cost of $600,000.
The work is expected to be completed over the next nine months.
For further information:
Simon Weston, Infrastructure & Services Group Manager
Phone 027 4464965