Factory to blame for toxic river

By ELIZABETH BINNING

High levels of bacteria which have made swimming in the Waikato River unsafe have been traced to a milk storage tank at Fonterra's Hautapu dairy factory.

Environment Waikato's resource use group manager, Harry Wilson, said the bacteria were discharging from a pipe that ran from the tank into the river 6.7km away.

The factory, just north of Cambridge, is owned by a Fonterra subsidiary, NZMP.

"The company has immediately stopped discharging and fixed the problem," said Mr Wilson.

"They were completely unaware of it as the discharge was never contemplated to contain any bacteria."

Last month, river bacteria levels tested more than seven times over the national safety limit for swimming and the Waikato medical officer of health, Dr Dell Hood, warned people to stay away from the water.

As Environment Waikato searched for the source of the pollution, there were concerns it was coming from sewage, but Mr Wilson said that possibility could now be ruled out.

"The discharge is low-strength dairy waste. It is not human waste."

NZMP has the council's consent to discharge wastewater from the tank into the river.

But an investigation has started to find out how the bacteria built up.

If negligence is found, the company could face legal action.

NZMP's global director of manufacturing and milk supply, Max Parkin, said the storage system and pipeline were supposed to carry only clean-water discharge and the company had no idea bacteria were growing inside.

The pipe and storage system had now been cleaned.

"It is an unfortunate situation that could not have been predicted."

At its peak the Hautapu factory processes more than four million litres of milk a day and produces more than 66,000 tonnes of dairy products a year.

Mr Parkin said the company had spent a lot of money improving its wastewater systems in the past 10 years.

Much of the wastewater was now recycled, used to clean the factory and then sprayed over neighbouring farms.

The recycled water was tested for bacteria every 12 hours, but the milk storage tanks, which were not deemed a high risk, were not tested as often.

More regular testing would now be conducted.

Environment Waikato will also continue testing the river.

Mr Wilson said bacteria levels were expected to reduce to their normal "background levels" within a few weeks providing no other sources of contamination were found.