Cause of sewage overflows at dump station under investigation

One of the Te Ahu pump station effluent chambers' cross grate which keeps getting blocked and overflowing. Photo / Supplied

A popular Far North recreational vehicle facility is being investigated this week following a persistent sewage overflow issue at the country's northernmost dump station.

Between December 17, 2021 and January 6, 2022, four requests for service were filed to the Far North District Council (FNDC) due to an ongoing problem of effluent leaking out of the dump near Kaitaia's main road.

The station is managed by FNDC's town maintenance contractor Recreational Services but Ventia, a private company that manages the council's wastewater schemes, assists with callouts.

According to the council, Ventia staff visited the station the same day each complaint was received and each time, blockages were cleared and the area washed down and disinfected.

The dump station is located in the public car park behind Kaitaia's Te Ahu Centre, at the corner of Matthews Ave and South Rd, and is unlocked to ensure easy access by recreational vehicle owners.

The centre also houses the i-SITE Visitor Information Centre.

Recreational vehicle owners discharge the contents of their septic tank into a sump via a flexible, greywater hose that is supplied with the vehicle.

The system is gravity-fed and there is a pre-grate above the channel system to prevent objects from going down the line.

It is connected to the council's wastewater reticulation network rather than a septic tank, so there is no limit on the number of people who can use it.

Some recreational vehicle owners flush wet wipes and other non-biodegradable objects down their sumps which can cause blockages, especially if people don't wash the grate after use.

According to an FNDC spokesperson, the underlying cause of the blockages has not yet been established.

This will be investigated this week, along with the need for signs explaining correct use of the dump station.

"The council has requested that Ventia monitor the station daily until the source of the problem is identified and addressed," the spokesperson said.

Te Ahu Charitable Trust director Mark Osborn said he was grateful the council had responded to the blockages.

"I am pleased they are going to investigate the cause of blockages, as well as consider the need for signage explaining correct use of the dump station," Osborne said.

"Although Te Ahu is not responsible for the station, because the old dump station used to block often, the drain pipe under the car park was upgraded from 100mL to 150mL during construction of the centre."

Osborne also believed many people driving at nearby beaches also used the high-pressure water at the station to rinse their cars, which often resulted in large quantities of sand running back into the drain potentially contributing to the problem.

The Northland Age was contacted by a concerned reader who had made reports to council and to the Ministry of Health (MoH) when the system was discharging into the street.

The Age contacted MoH for comment but a reply was not received in time for the edition.