Beach Road Pressure Sewer Systems, Kaikoura NZ

Kaikoura District Council
Kaikoura, New Zealand

To support Kaikoura District Council's recovery from one of New Zealand's most devastating earthquakes, Aquatec replaced severely damaged gravity sewer infrastructure with a network of customised pressure sewer systems servicing both residential and commercial properties.

Rebuilding essential services destroyed by a natural disaster

Just after midnight on the 14th of November 2016, a 7.8 magnitude earthquake struck 60 kilometres south-west of Kaikoura, a coastal town on New Zealand’s South Island. In just two minutes, the destruction caused was immense and unprecedented – the quake generated the strongest ground acceleration ever recorded in the country, damaging over 100 structures, claiming two lives and creating a rupture 160 kilometres long.

As part of the road to recovery, Kaikoura District Council (KDC) commenced their largest ever capital program in order to restore severely damaged essential infrastructure, including the wastewater system which had been displaced by the collapse of the Lyell Creek embankment areas. Aquatec were nominated by KDC after a rigorous evaluation process to re-sewer the Beach Road portion of the township, replacing badly damaged sewer pump station structures and gravity mains with a new cost-effective and non-invasive pressurised sewer network.

Customised systems to overcome challenging site conditions

The repair and upgrade of the Beach Road network involved replacing 1.5 kilometres of sewer main from the Hawthorne pump station to the Mill Road pump station. Rebuilding the existing gravity sewer ‘in-situ’ was investigated, but soil conditions, high groundwater, and the proximity to a creek made this impossible.

Instead, Council tendered the project based on a pressure sewer scheme, connecting multiple residential and commercial properties into new pressure sewer systems. These systems incorporated customisable collection tanks to suit ground conditions, built of FRP rather than concrete to allow for some seismic movement, containing specialised grinder pumps to handle commercial flow rates and transfer the raw sewerage via shallow, small-diameter pressurised rising mains.

Aquatec were awarded the tender for supply of pressure sewer systems for the rebuild, providing contract management to KDC but liaising with their nominated installation contractor Fulton Hogan to work through specific project-related challenges such as changing chamber locations and various trafficable lid options.

“The Aquatec offered pumping system does have a stronger record in operation and maintenance with fewer callouts and noted issues. The Aquatec pumps are oil rather than air cooled and have fewer wearing parts. As such, there are less consumables required, and unplanned events are less frequent.”

— William Loppe, Rebuild Programme Manager, Kaikoura District Council

Solutions tailored to unique project requirements

  • Aquatec’s tender submission was successful as it presented the highest Net Present Value with lower whole-of-life costs for KDC as the network owner and operator. Aquatec provided a greater understanding of the roles and responsibilities of the Supplier in the context of the overarching program, committing to senior staff being in Kaikoura for critical periods of the project to support the civil contractor and consult with local residents and homeowners.
  • The Aquatec systems were custom built for the specific application to service a combination of residential and commercial properties (130 lots in total). The Aquatec pumps, being suitable for use across both applications, enabled KDC to maintain consistency of equipment, while the control panels provided full remote communication without the need for third party hosting.
  • Both Simplex (single pump) and Duplex (dual pump) systems were utilised, with a range of chamber sizes from 1,500 to 13,000 litres capacity. The heavy duty FRP tanks are designed to withstand the seismic conditions and are engineered for fully water-charged ground. Aquatec also completed trafficable load rating design for each pump station.
  • The adoption of Aquatec’s unique pressure sewer technology resulted in the new sewer network being installed with minimal disruption. Aquatec’s OGT (turbine) pump, designed for a maintenance free operational period of 20 years, means that ongoing operational costs are extremely low. The community of Kaikoura now has the opportunity to connect to a fully reticulated, environmentally safe wastewater system.

“Referee checks have highlighted and confirmed the strong performance of Aquatec products. The Aquatec representative has been pleasant to work with, very cooperative and commercially arranging where appropriate.”

— William Loppe, Rebuild Programme Manager, Kaikoura District Council