The amount and content of wastewater from industries like Affco and Tasman Tanning is set to be monitored 24/7 under a new Whanganui trade waste bylaw.

Whanganui District Council's statutory management committee met on March 20 to hear submissions on the proposed bylaw. There was only one submission, from the Sustainable Whanganui Trust.

The trust supported 24/7 monitoring, saying it would be impossible to treat waste without knowing how much there was or what was in it. It largely approved the bylaw.

"Above all we welcome this being the end to discharges into the sea which are only milliscreened," the submission ended.


No one came to speak to the committee, and no changes were made as a result of the submission.

The committee agreed unanimously to recommended council adopt the bylaw.

About 80 per cent of Whanganui's wastewater is from industry but no industries made submissions. Whanganui Mayor Hamish McDouall said one had to assume they were happy with what was a "pretty standard" bylaw.

It doesn't mention the costs to industry to have their wastewater treated. He expected industries would address that through the 10-year plan process.

The 2018-28 draft plan sets out that major trade waste businesses will pay their share of the new plant's cost in a targeted rate over 25 years. They will also pay for treating and disposing of their own waste.

Charges for domestic toilets remain unchanged and tankered waste will cost $10 per cubic metre.

Cr Rob Vinsen asked whether action could be taken under the new bylaw if Tasman Tanning's wastewater has excessive levels of chromium, a heavy metal used in tanning.

If there is too much heavy metal the Bonny Glen Landfill won't take Whanganui's solid waste and it will have to be trucked to Hampton Downs, in north Waikato, for disposal.

That's expensive, council senior wastewater engineer Arno Benadie said, and Tasman would have to pay for it. But he didn't think it was likely to happen.

"Tasman have installed a chromium recovery plant on site. Once it's up and running it will recover 98 per cent of all the chromium."

If levels started to rise monitoring would detect it and let Tasman know well before excessive levels were reached. Dried solid waste from the treatment plant may be usable as fertiliser if it doesn't contain high levels of heavy metals.

Excessive volumes of waste from the Affco meatworks were also a concern for Mr Vinsen, and they triggered the plant's smelly breakdown in 2013.

Affco contributes a lot of wastewater in summer, and was consulted on the plant's design. The upper limit for wastewater was set as high as possible to suit the meatworks.

"If the load is too high for a long time we will be in trouble, but I don't expect any problems," Mr Benadie said.

Relationships with the industries have improved. Mr McDouall said meetings with them were now "more collaborative than combative".

When the new plant starts operating industries whose waste incurs extra cost by blocking the system or needing expensive analysis will pay those costs.

The bylaw sets many standards for the wastewater. It must not be over 40C, have solids bigger than 15mm or excessive levels of ammonia, pesticides or heavy metals.