Seaview Wastewater Treatment Plant. Photo: Supplied / Wellington Water
Greater Wellington Regional Council could dish out fines or take legal action if upgrades to address the stench at a Lower Hutt sewage plant are not done on time.
Between 31 October and 12 December 2023 there were 111 complaints about odours coming from the Seaview Wastewater Treatment Plant.
On 19 December, biofilter work to address the smell was completed, but between 12 December 2023 and 9 July this year there have been a further 312 complaints reported to Greater Wellington Regional Council in its capacity as a regulator.
The regional council has told RNZ that complaints reduced over winter but after an investigation by an independent technical expert, they found for the plant to be compliant, further upgrades to its biofilter had to be done.
The upgrades included replacement of the plant's biofilter air distribution system and installation of a new biofilter cell isolation system
As a result, on 15 August, the regional council issued Hutt City Council, Upper Hutt City Council and Wellington Water with an abatement notice which required the changes be completed by 4 October.
The parties would also have to do subsequent reporting to the regional council that details the work having taken place and testing to ensure the upgrades were working.
If the upgrades were not done on time, the councils and Wellington Water could face a fine or prosecution under the Resource Management Act.
Wellington Water Network Management group manager Jeremy McKibbin told RNZ they acknowledged the deadline in the abatement notice to complete the upgrades.
"Those works are underway, and while this is a tight timeframe, Wellington Water will be undertaking all appropriate efforts to complete the upgrade to comply with the abatement notice."
Both Upper Hutt and Hutt City Council told RNZ Wellington Water was carrying out the work on behalf of them.
In December last year, plant operator Veolia and Wellington Water were issued 13 fines each totalling $22,750 per company for the objectionable smells.
Hutt City Council and Upper Hutt City Council were also forced to pay $9750 each.