Urgent $1.4 million Dargaville wastewater sludge removal planned

Discussing Dargaville's sewage desludging at Kaipara District Council's meeting. Photo / Susan Botting

Urgent removal of 3000 tonnes of treated human waste from Dargaville wastewater treatment plant's oxidation pond moved a step closer on Wednesday with Kaipara District Council approving a $1.4 million sludge removal operation - strongly opposed by one vocal councillor.
Tangowahine-based Kaipara District Councillor Victoria del la Varis-Woodcock, questioned the urgency of the sludge removal plan, told the meeting community - including tangata whenua - should have been consulted more and added that the option chosen for sludge removal was not a positive choice, given the oxidation pond's location.

The Love Kaipara waste minimisation programme manager said other options should instead be investigated. She stood aside when all other councillors voted in favour of the action - due to having already publicised her views opposing the option on her social media pages before the meeting.

Kaipara mayor Jason Smith, deputy-mayor Anna Curnow and the other remaining six councillors all voted to proceed with removal of the oxidation-pond treated sewage sludge.

Dargaville's wastewater treatment plant oxidation pond hasn't been cleaned out since 2009 and is now 80 per cent full. The council plans to empty out the sludge next year, subject to successfully gaining Northland Regional Council resource consent.

"We have a matter that is urgent and must be addressed. We need to proceed with the desludging," Curnow said.
"Unless good operational maintenance is undertaken, it (the oxidation pond) will fail," Peter Wethey, Mangawhai Heads-based councillor told the meeting.

"Councillors are always in the business of measuring up the risks, benefits and budgets. I am reassured lots of different options have been considered (by appropriate Kaipara District Council staff) and those considering these have come to the decision this is the most sensible option," Curnow said.

Maropiu-based councillor Karen Joyce-Paki (Ngāpuhi/Ngāti Whātua) from near Kaihu, said tangata whenua would have their chance to put forward views on the sludge removal during the publicly-notified resource consent process for the works.

"I'm excited about the opportunity Māori have to be part of the decision making process – section eight of the Resource Management Act requires us to give effect to the principles of the Treaty of Waitangi, allowing for Māori participation in the process," Joyce-Paki said.

"Māori will agree, we can't do nothing," Joyce-Paki said.

Resolving the oxidation pond sludge removal would benefit Māori and the wider community.
Kaipara District Council (KDC) staff are now putting together a resource consent application to submit to Northland Regional Council.

Engineering company Geotech has been awarded the sludge removal contract. This will see pond sludge put into giant wine-bladder-like "geotechnical dewatering bags" which lie flat on the ground in the sun for at least five months so their contents' water component evaporates. The biodegradable bags will then be covered with topsoil and grass.

Dargaville's oxidation ponds are at Awakino just east of the Kaipara town. Their location at the confluence of Awakino and Northern Wairoa River was cited as a reason not to use the "geotechnical dewatering bags" managementby del la Varis-Woodcock.
"What if we have floods like in 2014 combining with a very high tide and high groundwater levels," del la Varis-Woodcock said.

Jim Sephton, KDC general manager-infrastructure services, said flooding would not be a problem.

Del la Varis-Woodcock said other options needed to be checked out. Sustainable infrastructure management into a climate change challenged future was an important consideration.

She was told consideration of other options would be part of future discussion. But the situation with the oxidation pond being 80 per cent full needed immediate attention.