Dunedin City Council

Through our local office, we've been working with Dunedin City Council to successfully deliver 'three waters' (wastewater, stormwater, and drinking water) upgrades.

As a member of the Council's works panel, we are one of a small number of organisations upgrading the city’s water and wastewater treatment plants through to 2031.

Our work includes scoping, optimising, designing and delivering a variety of packages across the Council's three wastewater and six clean water treatment plants.

Click on the boxes below to expand them for more information about some of the projects we're already completed.

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In late 2022 Dunedin City Council (DCC) selected McConnell Dowell as the lead civil contractor for their Water and Wastewater Treatment Plants Upgrade. The formal contract for the $140M eight-year programme was signed in early March 2023. The scope includes optimising, designing and delivering capital renewal work for the city’s three wastewater treatment plants and six freshwater treatment plants. This includes:

• Civil and structural engineering,
• Building and construction,
• Process plant,
• Mechanical engineering,
• Electrical engineering,
• Controls and SCADA (Supervisory Control and Data Acquisition) Systems,
• Bespoke supply, delivery and installation.

The project team includes DCC operational staff, McConnell Dowell (lead contractor) Stantec (design) and Lutra (process engineers).

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Area C:

• Approx 2600m of new water main, stormwater and wastewater pipelines being:
• 850m water
• 1200 wastewater
• 410m stormwater
• Pipes ranging in diameter between 150mm to 375mm Upvc
• Depths ranging between 0.75m – 2.6m

Area F:

• 3800m of new water main, stormwater and wastewater pipelines
• Diameters and material ranging from 150mm OPVC, 180mm -250mm PE
• Installation of hydrants, valve clusters, live cut-ins, new water meter and manifold boxes and connection to all private laterals

Area E:

• Wastewater -400m, 150mm PVC
• Depth up to 2.8m to invert -150mm PVC & 180mm PE
• Open trenched and pipe cracked
• Installation of Manholes and connection to all private lateral connections
• Working in the water table and private property

Area D:

• Water – 550m of water pipelines
• diameters and material ranging from 150mm OPVC, 180mm PE
• Installation of hydrants, valve clusters, live cut-ins, new water meter and manifold boxes and connection to all private laterals
• Open trenched
• Wastewater – 680m
• Stormwater – 200m
• Drainage depths up to 2.8m to invert - diameter 150mm – 375mm PVC
• Open trenched, pipe cracked and drilled
• Installation of Manholes and connection to all private lateral connections

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The project involved pipework and connection upgrades to the wastewater network at and around the Musselburgh Pump Station. The team constructed new diversion pipework from dry weather pumps 1 and 2. Outside the station, the team trenched down the road to connect to the existing pipework downstream of the damaged manifold. This project was completed in July 2024.

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Our Dunedin team is upgrading 2100m of water main between Hagart-Alexander Drive and the Wingatui Water Reservoir in Wingatui and Mosgiel,

This project includes upsizing the pipeline 300mm to a larger diameter 450mm increasing the network’s capacity and strengthening supply to the Mosgiel community. Phase One of this project was completed in August 2024 and Phase Two commenced at the end of October 2024. This work is expected to be completed by July 2025.

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The project scope included upgrading the new intake structure at the base of the draw-off tower, and to achieve this the team had to divert the river away from the inlet by 300 metres. Temporary pumps and pipes supplied water while the inlet was out of action. The valve work used for the temporary over-pumping was left in place for future use. We also built a set of stairs to make future access easier and planted natives at the adjacent overflow to help improve stormwater drainage. The inlet works were completed in April 2024.

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As part of the 3 Waters Framework Project, the Green Island chemical plant upgrades project required a new sodium hypochlorite tank, new dosing pumps, new reticulation with leak detection and a new Aeration Tank spray system. This project was completed in August 2024.

The project scope included:

• Installing new dosing pump electrical cabinets and a tank
• Calibrating and testing them during cold commissioning
• Leak testing
• Fitting the delivery point
• Installing an aeration tank spray hose

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