As part of Stronger Christchurch’s infrastructure rebuild in New Zealand, the Christchurch suburb of Southshore is currently having a pressure wastewater system installed by horizontal directional drilling.
Fulton Hogan will be installing the new pressure wastewater system, which consists of a pumping unit installed on private property and connected to the existing private wastewater lateral. The pump transfers wastewater under pressure to the new pressure wastewater main.
Stronger Christchurch (SCIRT) said that Fulton Hogan is using horizontal directional drilling (HDD) to install the wastewater mains to minimise disruption. HDD will be used to install approximately 75-100 m of pipe at a time.
Local resident Mark Smith told SCIRT that the HDD installation in his area has been seamless. “The installation happened over a few days, and apart from the new pump in the ground and the wall unit, both discreetly sited, you'd hardly know that things had changed,” Mr Smith said.
The existing gravity wastewater pipes in the Southshore area suffered multiple breaks due to the 2010 and 2011 earthquakes. SCIRT said that the pressure wastewater system is more resilient in any future seismic events, as it allows the use of shallower, more flexible pipes.