A public pool, a water treatment plant and a landfill owned by Hamilton City Council are among the 99 organisations caught dumping contaminants down the drain.
The three council-owned facilities were revealed after the council released the names of all 99 companies that had breached their trade waste consents in the city during the past year.
The council had initially refused to say who the 99 were, but after RNZ revealed last month that 267 companies had dumped contaminants down the drain, it said it had since changed its mind.
"We note that the factual circumstances surrounding this matter have changed since the release of the initial RNZ report and we now consider the public interest in this matter to be high and outweigh any good reasons to withhold this information," Hamilton City Council said in a statement.
The council-owned and operated Waterworld Te Rapa, Horotiu Landfill and a water treatment plant were all caught discharging contaminants into the sewers in breach of their trade waste consents, multiple times, according to the information released.
The water treatment plant incurred three "medium" risk breaches, namely discharging too many suspended solids. In July last year it dumped nearly twice the allowed amount of total suspended solids.
Waterworld Te Rapa was also caught discharging waste water containing too many suspended solids, and on another occasion its pH was non-compliant, while Horotiu Landfill discharged too much nitrogen-rich leachate on two separate occasions.
Contaminated wastewater can damage public infrastructure, such as pipes and wastewater treatment plants, and, even once treated, can also potentially damage the environment it is eventually discharged into.
Hamilton City Councillor Dave Macpherson, who pushed for the names to be released, said it was a "surprise" to learn about the council's breaches and it was disappointing councillors were not previously made aware of them.
"The whole process has shown that the city council is not as transparent and open as we'd like it to be," Macpherson said.
He had been promised the council would now be presented with such information in the future, he said.
"This will drive some reasonably quick changes in this area, not just in trade waste, but also in other information we hold," Macpherson said.
The council should have been more transparent in naming the firms caught breaching their trade waste consents in the first instance, he said.
"I am not particularly happy that it took a media report for us to find out about this - and while self reporting of such breaches is certainly to be commended, what is also important is public confidence that both our systems and our transparency are up to scratch.
"This is elevated by the public concern over the high lead levels in the public water supply issue going on in Dunedin at the moment.
"I think we have erred on the side of keeping the business community sweet, rather than a balance that includes taking the community into our confidence," Macpherson said.
Supermarket among 'high-risk' breaches
The list also named 16 firms caught with what the council considered 'high-risk" breaches in the past year.
They included Pak 'n Save on Mill Street, aluminium products manufacturer Altus, chemical maker Ecolab, cardboard manufacturer OJI Specialty Fibres and agritech company LIC Riverlea Road.
Overall, most of the breaches incurred by the 99 companies were minor or "technically non-compliant, the council said.
These included issues such as dirty grease traps in cafes, supermarkets or restaurants, or tests not conducted on time, the council's infrastructure operations manager Eeva-Liisa Wright said.
"We work with businesses to improve processes and seek to prevent non-compliance through an open and co-operative approach with our consent holders.
"This relationship means we can identify minor non-compliance issues and resolve them with the business before they become an issue which adversely impacts our systems, the environment or our people.
"This co-operative approach means many of our consent holders self-report and resolve breaches, which allows continuous improvements in processes and, overall, reduces the risk of a significant breach caused by a lack of process," he said.
"Many breaches are of a technical or procedural aspect of the consent, or are relatively minor breaches of allowable limits. All breaches are taken seriously, investigated and processes put in place to resolve the issues, but our approach is to educate and work in partnership with our consent holders where possible to ensure the best long-term outcomes for the city."
Japanese owned Oji Fibre Solutions (OjiFS) said it was very disappointed in the trade waste excursions at its Levin and Hamilton packaging sites.
The company, which manufactures pulp and cardboard packaging products, operates eight facilities across New Zealand with six holding trade waste permits.
The breaches occurred because its internal management systems were not fully adhered to, group manager environment and external relations Philip Millichamp said.
"Any excursion is unacceptable, it is a big wakeup call for us because we thought we had very good compliance management and reporting systems, but this shows we need to improve," he said.
"At Levin, the council charged us for the elevated levels and the discharges were reduced back below the contractual limits and, at Hamilton, we were given time to install new treatment equipment to meet the limits, which has been completed this month, so the incidents have not been ignored and have had no adverse effect on the environment," Millichamp said.
"However, the fact that trade waste discharges are treated by the council before entering the environment does not take away our responsibility to honour our agreements with councils very seriously," he said.
OjiFS was upgrading wastewater treatments at its Tasman Mill near Kawerau and at the Kinleith Mill near Tokoroa, which would reduce discharges to the Waikato River.
Oji had high environmental standards, and the company was proud of the commitments it had made to improve its performance, so it was disappointing that these incidents had not measured up, he said.
Other companies respond
Pak 'n Save owner Foodstuffs said all its stores took their responsibility to monitor and reduce waste very seriously.
The store [Mill Street] is working with its third-party trade waste monitoring agencies to ensure its systems are robust and local council regulations are upheld, a spokesperson said.
Chemical manufacturer Ecolab, which recorded 17 breaches over the past year, including 15 high risk breaches, said it was a responsible company and committed to sustainable operations.
We have been working closely with the Hamilton City Council regarding the outflow levels from our plant into the city's wastewater treatment plant. Trade waste breaches can result when changes in operations occur, such as an increase in manufacturing output or a changeover in product lines.
Over the last three years, we have invested more than $14 million in our plant, including upgrades to our wastewater capture and treatment processes.
We have modified our wastewater system monitoring and controls, and over the last five months, have significantly reduced our trade waste breaches, with four occurrences since 1 September.
We are planning additional cleaning, filtration and water recycling improvements at our plant this year, it said.
Agritech company LIC, which had multiple high risk breaches, was also trying to improve its processes, LIC general operations and service manager David Chin said.
The wastewater that is being discharged comes from a wash line that cleans and sterilises testing equipment that contains a small amount of milk residue.
Our current consent is based on an annualised target. LIC operates a seasonal business and at peak loads we have breached the annualised limits. This was identified through our own monitoring.
We proactively provided the council with this monitoring information and we continue to provide this information on a more regular basis than what our consent requires.
We have been working with the Hamilton City Council very closely on mitigation plans for the intermittent breaches that we experienced.
Multiple process changes have been made and continue to be made to decrease the contaminant load entering the trade waste system. With all the changes we have put in place we are confident that we will meet the consent conditions at peak volumes moving forward, Chin said.
Altus, an aluminium products manufacturer, said its five breaches occurred when it was commissioning a new powder coating machine and waste treatment plant.
This took some time to settle in and strike the balance between water consumption and consent conditions. As such, we became aware that we had breached consent conditions and reported this to the council. We worked closely with suppliers and are confident we now have corrective actions in place to minimize this risk.
Altus operates a world-class aluminium press and paint-line operation having made significant investments in more sustainable equipment and processes in recent years, and is constantly looking for ways to improve both efficiency and lessen its environmental impact.
The Ombudsman has asked Auckland Council's Watercare, as well as New Plymouth, Waikato and South Taranaki councils to reconsider their refusal to name companies caught breaching trade waste consents, in light of Hamilton City Council's decision.