He told the Chronicle he is not alarmed by it, because the treatment plant was designed to cope with increased capacity. Also, he's been told the sheep and lamb skins being processed in the new contract will replace cattle hides and will not result in more wastewater.
He has been told most of the skins will not be tanned, only semi-processed for export. Chromium is not used when tanning sheep and lamb skins.
Giving him additional comfort, Tasman Tanning had indicated it was installing new machinery to further treat the effluent and at the same time develop cleaner technology for processing, he said.
Asked about the contract, Tasman Tanning sent a publicity excerpt. It said the plant had invested more than $2m in new dyehouse equipment.
"This investment is continuation of our drive to improve energy efficiencies, sustainable practices and increase production.
"Not only does increasing production benefit our Tasman customers, but the local economy benefits as we create more jobs for our wider Whanganui whānau (family)."
The council has been working with Tasman Tanning on reducing its chromium discharge since 2018, Fell said.
The chromium stops bacteria in the wastewater treatment plant working properly, a Whanganui District Council document sent to Horizons Regional Council and obtained by RNZ says.
As a result of this, wastewater has been discharged to the sea with excessive faecal coliform levels.
High chromium levels at the wastewater treatment plant can create bacteria die-off, Fell conceded. But he said the plant was functioning well.
The other problem with the chromium was that it made dried sludge from the plant unsuitable for application to land. If chromium can be reduced to less than 5g per litre or 10kg per day the sludge could be applied to marginal coastal land or become a compost additive.
Fell's technical experts say this is a viable option. But as long as chromium levels are high the sludge has to be disposed of in an empty pond near the plant.
The pond will be full in two or three years. After that the council could dig another hole for the sludge, or it will have to be expensively trucked to Hampton Downs Landfill in Waikato.
The company had greatly reduced its discharge of chromium in the past two years, and was heading in the right direction, Fell said. It has to meet the council's permitted level.
The council cannot fine it or increase its trade waste charges, but it has other means of enforcement under its trade waste bylaw.
"Whanganui District Council is highly proactive in monitoring discharges to the wastewater treatment plant every day," Fell said.
In January an RNZ investigation into wastewater consents around New Zealand revealed the Tasman Tanning plant in Whanganui clocked up 570 fat, sulphide and chromium breaches over the past year.
RNZ asked Silver Fern Farms head of communications and sustainability Justin Courtney what due diligence had been done before the contract was awarded to Tasman Tanning and if it was aware of the company's repeated wastewater breaches.
He declined to give an interview, but provided the following statement:
"Silver Fern Farms have had a long-standing commercial relationship with NZ Light Leathers/Tasman Tanning. As part of the relationship we have discussed their environmental improvement programme, which has shown progress toward international environmental accreditation, and has been backed with a multimillion-dollar investment in additional treatment process infrastructure."
