Land Meat New Zealand has been convicted and fined $66,500 for illegally discharging wastewater into the Whanganui River.
Horizons Regional Council was notified of the discharge by the Whanganui District Council on March 2, 2017 after it discovered contaminants in its stormwater system.
Following an investigation, Horizons pressed charges against Land Meat NZ, which was unsuccessful in defending itself at a hearing in Whanganui District Court last year.
Environment court judge Brian Dwyer made the ruling in Whanganui District Court on Tuesday.
Horizons group manager, strategy and regulations Dr Nic Peet said they felt that the sentencing was an appropriate result.
"[It] sends a clear message to commercial and industrial businesses that they need to carefully manage their operations to ensure they comply with the required environmental regulations.
"If they fail to do so they risk the imposition of significant fines and convictions."
During sentencing the court noted that Land Meat NZ had been highly careless, the discharge was significant and could have had serious effects on the Whanganui River.
"The pump, along with a back-up pump, blocked, resulting in meat processing wastewater flowing on to land and into stormwater drains, and potentially into the Whanganui River," Peet said.
"The state of the Whanganui River is of utmost importance, it has significant cultural and recreational value to the wider community, so the responsibility for its health lies with us all."
When approached for comment, Land Meat New Zealand released a statement.
"There was a discharge of tradewaste from the Land Meat site on 2 March 2017 due to an unexpected mechanical failure of the tradewaste pump.
"The court accepted that the effects of the discharge were adequately mitigated and its response to the overflow was described as brilliant.
"Land Meat received a discount in sentencing for good character and for having no previous convictions."
The sentencing precedes another instigated by Horizons, who pressed charges against Whanganui District Council after a Powerco fuse failed in January 2017.
The failure caused human wastewater from a district council pump station to overflow into the Mowhanau Stream.
Whanganui District Council was convicted on two charges of discharging contaminants into water in Whanganui District Court in July and will be sentenced on November 1.
Horizons Regional Council has two further prosecutions ongoing, which are not Whanganui-related and cannot currently be commented on further.