Parua Bay Wastewater Scheme

The wastewater system is designed to take the wastewater that comes from showers or baths, washing machines, toilets and other household or business sources, keeping it separate from stormwater.

In Parua Bay, the wastewater system pipes the wastewater to the storage tank, and it is then pumped through to the main wastewater treatment plant in Whangārei. 

The stormwater system is designed to gather the rainwater that flows off the land and rises up through the ground, keep it separate from the wastewater system, and direct it into streams, ponds or the sea.

Inflow is when stormwater flows into the wastewater system from above ground from: 

• places where downpipes are draining into gully traps 
• gully traps that are underneath leaking spouting / guttering 
• damaged gully traps or gully traps that are set low that enable stormwater to drain into them 
• non-compliant connections, stormwater connections to the wastewater pipelines 
• places where stormwater forms ponds that are higher than the gully trap, letting water flow in. 

Infiltration is when water builds up in the ground. As the level rises the pressure on pipes under the ground increases and water can escape into pipes, including wastewater pipes, through holes or cracks or poor connections. 

We are investigating the catchments around the Parua Bay storage tank to establish how much stormwater is making its way into the wastewater system, and where it is getting into the system. Investigations have included site visits and questionnaires to residents.

In November 2024, we began smoke testing each of these catchments. This involves blowing smoke (vapour) into the wastewater pipes and seeing where it escapes. Where the smoke is getting out could be the locations where the stormwater is getting in.

Mapping

This information will be mapped, so we can see where the 'hotspots' are. From there, if improvements are required, we will be talk with community members about what needs to be done on the properties, while we address problems on public property.

Keeping the tanks empty 

While we are finding out where the stormwater is getting into the wastewater pipes and working out how to stop that from happening, we are emptying out the storage tank(s) by sucker truck, so they can contain the maximum amount of wastewater volume. 

The sucker trucks

Sucker trucks are removing wastewater from the wastewater storage tank at Parua Bay to free up storage capacity and taking it to the wastewater treatment plant on Kioreroa Road.  

The smell 

Opening the cover at the pump station when we began emptying it caused an odour problem, so we have modified the lids and will not need to fully open them as often in future. 

When we have completed our investigations and undertaken immediate repairs and improvements, we will have a clearer idea of what needs to be done to meet the needs of the community now and into the future. Planning, design and construction work will begin at that point.