Tom McDowall's Kawerau vermicast operation, which uses worms to turn biosolids from council wastewater treatment plants around the Bay of Plenty into fertiliser, continues to expand. Photo: LDR / Troy Baker
A worm farm that's been the subject of more than 130 odour complaints has been given the green light to expand its Kawerau operations.
Vermicomposting company Ecocast has been granted a 25-year resource consent to grow its existing plant by 5.5 hectares.
Ecocast owner Tom McDowall said the expansion would allow the company to improve its control of smells coming from the site.
McDowall, a former manager at the Kawerau District Council, said he was pleased with the outcome of the consent renewal and expansion application to Bay of Plenty Regional Council.
The worm farm takes biosolids from wastewater treatment plants throughout the Bay of Plenty, mixes it with wood fibre from nearby mills and processes it into vermicast fertiliser.
The operation has been the subject of over 130 odour complaints to the regional council since September 2020, and there was a breach of an abatement notice in January 2024.
At a hearing before independent commissioner Gina Sweetman on 10 December, employees of the neighbouring log yard (operated by Manulife Forest Management) described the "nauseating" smells wafting from the worm farm over the past decade.
On one occasion it was found that the biosolids had not been mixed with wood waste material before being laid out into windrows, as there had been insufficient wood fibre stockpiled.
At the submissions hearing, it was made clear the odours were strongest when the biosolids were being unloaded from delivery trucks, before they were covered with wood fibre.
McDowall said the plant's expansion would make it easier to control any odours from the Tarawera Road site.
Another bunker for unloading the biosolids further away from the neighbouring log yard will be part of the expansion onto a neighbouring property.
"We're really pleased with the outcome of the consent renewal process," McDowall said.
"I think we got on really well with the submittors - positive and negative. It will be a positive, from an odour point of view, for our neighbours because we will be able to control it better."
Conditions of the new consent include a limit of 32,000 tonnes of raw materials (not including the wood fibre) to be brought onto the property over any 12-month period.
It requires at least three days' supply of inert substrate (wood fibre) to be stockpiled at all times and four days' supply of weedmat and lime to be stockpiled - to be placed over windrows in the event they become odourous.
There is to be no stockpiling of biosolids from wastewater treatment plants. All raw material being delivered to the site is to be immediately covered by a layer of wood fibre to reduce odour.
A complaints register is also to be maintained on site to record any reports of odours, what caused them and what was done to mitigate the odour. This register must be made available to Kawerau District Council on request.
Representatives of Ngāti Tuwharetoa (BOP) Settlement Group must also be invited to form a tangata whenua liason group with the consent holder to provide cultural perspectives and mātauranga on all matters pertaining to the operation of the site.
McDowall said the company was happy to comply with all the conditions set out in the consent.
He said he had not had any complaints about the odour in recent weeks and the regional council had not made them aware of any complaints made through its Pollution Hotline.
People who made submissions on the consent application have until 7 February to appeal the decision.
LDR is local body journalism co-funded by RNZ and NZ On Air.
