A company which spent more than $1 million trying to stop foul smells escaping from its rendering plant has been fined $13,000 after another stinky airborne discharge.

Hawke’s Bay Protein Ltd operates an animal waste products rendering plant at Awatoto, just south of Napier.

It holds a resource consent which allows it to discharge contaminants into the air, as long as they don’t cause an “objectionable or offensive” odour beyond its site boundary.

In 2021, the company was fined $38,000 for breaching this rule five times, and this followed seven other infringement notices for odour discharges since 1997.

However, in the latest case, Judge Melanie Dickey accepted that the discharge was the result of “teething problems” with an upgrade to the company’s system to control the smell, and commended its efforts to stem the problem.

Her judgment in the Napier District Court noted that there had been no further complaints since the latest offending discharge, in March 2021.

The company had already invested in an overhaul of its extraction system costing more than $1 million but the Hawke’s Bay Regional Council received complaints about odours from the site in February and March two years ago.

The council prosecuted Hawke’s Bay Protein over the March 2021 discharge after a nearby resident complained of a “strong sewage type odour”.

The odours identified included rotting meat, animal effluent and waste, as well as a bark-filter smell.

The company investigated and traced the cause to the volume of air going to a biofilter, according to court documents.

The company told the court the discharge was essentially the result of “fine-tuning” the upgrade to its extraction system, which included replacing the biofilters.

“The lack of odour complaints since March 2021 points to the success of that upgrade,” Judge Dickey said.

She found that the adverse effects of the discharge were low but the company could have exercised “more care in ensuring its house was in order” before using a new biofilter.

She fined the company $13,000.

Since the last discharge, the company has offered to make payments of $10,000 for boundary planting for residential neighbours who had been affected, and $10,000 for a wetland restoration project nearby.