Corder Park sewer pump station upgrade

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Consultant: Aurecon NZ Ltd
Project Manager: Nelson City Council
Budget: $5.3 million
Status: Complete
Time frame: 6 years

Project complete - April 2017

The final finishing touches are now complete and the pump station is fully commissioned and operating as expected. Thanks to everyone, especially nearby residents, for their patience as this project presented some unexpected challenges and took longer than expected to complete. We now have a facility that is able to handle current and future demand, safely and efficiently. 

Progress

March 2017

The new pump station is practically complete and the contractor is completing operational training and system control adjustments. There have been some ongoing odour problems at the site with some chambers still open to atmosphere but also some teething problems with the Ozone injection system. The odour control system needs further fine tuning to get the correct flow rate and contact time for complete odour neutralisation.

We apologise to local residents who have been affected and are endeavouring to get this right as soon as possible.  The remaining work of stripping out the old pump station, removal of overhead powerlines and reinstatement of the Atawhai Drive foreshore area is expected to be done by the end of March 2017.

February 2017

The bypass pipe has now been commissioned and the contractor is able to proceed with the new pipe connections for the pump station. Council and the contractor Downer NZ Ltd apologise to local residents for any inconvenience with noise during the night work that was necessary for this stage of the project.

The final pipe connections will also need to be done at night and that work should take around 3 hours but minimal noise is expected.

 All the remaining work on this project is expected to take a further three weeks with an expected completion date of 24 February 2017.

The Corder Park cycleway was reopened before Christmas and remains open to the public while the project is completed.

 December/January 2016/17

The bypass pipe has not yet been commissioned and the contractor has run out of time to complete work before the Christmas holiday period.

It would not have been acceptable to have the bypass in operation for an extended period of time over the break in case of extreme weather and high flows while the contractor was offsite. The remaining three pipe connections will now be completed in the New Year with anticipated site reinstatement by the end of January 2017.

Prior to Christmas the contractor will be cleaning up the pump station site and surfacing the cycleway so this can be reopened over the holiday period. We will provide further updates in January. Council and the contractor Downer NZ Ltd wish everyone a Merry Christmas and a happy New Year.  Please travel safely and look after your family and loved ones.

December 2016

The new pump station has been completed but connection of the new pipework has been delayed.

A pipeline failure in 23 July 2016 resulted in two new fittings needing to be installed for the connection of temporary bypass pipework. The bypass work has been reliant on good weather but Nelson has had uncharacteristic wet months resulting in high base flows in our sewer system. Flows could not be managed using the contractors original bypass methodology and a suitable window of opportunity has not become available.

Risk of a sewerage overflow to Nelson Haven has been taken seriously and considered in the contractors methodology.

This pipeline takes all the wastewater flow from Nelson City and cannot simply be turned off for any significant length of time during wet weather. The contractor would like to complete work before the end of the year and has installed a much larger bypass pipe to manage wet weather flows. Critical work now is to connect the bypass pipe during an overnight operation subject to dry weather flows. Once the bypass pipe is operational the remaining new pipe connections can be completed and the area reinstated.

 Council apologises for the inconvenience to the public who use this area and we can assure you that the contractor is making best efforts to complete the work.

October 2016

Wet weather has further delayed the reopening of the cycleway and commissioning of the pump station.  This work is now expected to be completed within the next month, subject to any further weather delays.

August 2016

Due to delays with the project, a revised time frame has been agreed as follows:

  • Removal of site fences and re-opening of cycleway expected by the end of September
  • Pump station commissioned and going live also by the end of  September
  • Decommission old pump station and foreshore/SH6 reinstatement work completed by mid October

The delay has been to ensure the correct methodology was in place to both maintain wastewater flow from the city and avoid the risk of any spills to Nelson Haven.

June 2016

This month final connections will be made to the existing pumping main, and installation and curing of the wet-well protective lining will be completed.

Once the wet-well can be filled with water then the new pumps can be tested and commissioned. All remaining remedial works including the structure's living roof and landscape planting will be completed during July. The pedestrian/cycleway through the site is expected to be opened to the public by mid-July.

 May2016

Some minor delays have been experienced with the project so it is now on target for completion in June.

February 2016: Electrical control system and generator will be installed this month. The pump station structure will be completed including all roof areas, new pipeline jointing and testing completed in time for the final connections to be made in late March. The pump station commissioning is still on track for early April with remaining remedial works and site landscaping to be completed by late April.

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January 2016:  The electrical control system manufacture is complete, pumps and valves have been installed and mechanical pipework  is complete and ready for testing. The gantry crane has been installed, the roof on the wetwell structure completed and equipment from Canada has arrived for the odour control system.

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December 2015: Construction is underway. Rock armouring of the foreshore for the new pipeline alignment is complete and landscape work has yet to commence. Construction and landscaping is expected to be complete by the end of April 2016.

Background

This pump station is located mid-way between Neale Park and the Nelson Wastewater Treatment Plant. In response to recent pipe failures that has seen sewage leaking out into Tasman Bay, the Corder Park pump station upgrade will replace both the existing pump station and a section of fragile concrete pipe along the foreshore area. The new pump station will also help to lower pipeline pressures back to Neale Park. This work will ensure the  future security of Nelson’s sewage management system.

Location