Seaview Wastewater Treatment Plant
Trial Shutdown Updates
6 December 2024
The trial of the shutdown of the odour neutralisers started on December 4. The community’s participation in the survey so far has provided us with vital information to help us assess the effectiveness of the neutralisers. Early results show varying levels of impacts based on location and weather conditions which we expected.
We appreciate the challenges to pinpoint the effectiveness of the odour neutralisers during the shutdown when other operational work continues at the Seaview Wastewater Treatment Plant. However, these are critical works to bring the plant back to optimal operational performance and reduce the risk of increased odour levels over the holiday period.
We encourage residents impacted by the odour from the Plant to continue to complete the odour survey and share it with others.
The trial will run for four weeks, and we’ll provide updates every 3-4 days through the interested parties email or on our website. Thank you for your feedback and understanding.
The Seaview Wastewater Treatment Plant serves a population of about 160,000 in Upper Hutt, Lower Hutt and Wainuiomata. The wastewater is treated or cleaned through a series of screens, tanks, bioreactors, clarifiers and ultraviolet treatments before being discharged into the open sea near near Pencarrow Head/ Te Raeakiaki where it is quickly diluted.
Consents
One of the nine resource consents permitting the operation of the plant, consent ‘WGN120142 [33408] Discharge Treated Wastewater to Stream ' expired in 2018. Prior to the expiry of this consent, Hutt City Council applied to Greater Wellington Regional Council (GWRC) for a new consent to temporarily discharge treated wastewater to the Waiwhetū Stream. While the reconsenting is underway, we continue to operate under the existing consent.
In general, the consents allow Hutt City Council to:
- discharge treated and partially treated effluent through an existing outfall,
- discharge mixed disinfected, treated and milli-screened wastewater during and/or immediately after heavy rainfall,
- discharge mixed disinfected, treated and milli-screened wastewater during maintenance,
- discharge of contaminants to the air,
- and to occupy the stream and coastal marine area with an outfall structure.
Join the Seaview mailing list
If you want to receive notifications and updates about the plant, please email customer.notifications@wellingtonwater.co.nz
Seaview Wastewater Treatment Plant monthly newsletter
For more information about plant activity and projects please go here
Odour treatment
Work is continuing to improve the capture of odours beyond the plant boundary.
Find out more about what’s planned and underway on the project page https://www.wellingtonwater.co.nz/projects/seaviewwwtp
The latest updates are available here
Investigation Reports
Seaview Wastewater Treatment Plant - Odour Deodoriser - Air Quality Assessment - October 2024
Seaview Wastewater Treatment Plant - Odour Investigation - June 2023
Seaview Wastewater Treatment Plant -Biofilter Flow Assessment -March 2024
Making a complaint
If you have a complaint about Wellington Water directly, please call 04 912 4470 or email customer@wellingtonwater.co.nz to access our free complaints process.
After hours, please contact the Hutt City Council Call Centre on 04 570 6666 / 0800 488 824.
Greater Wellington Regional Council is the regulatory agency for reporting airborne discharges 0800 496 734.
Complaints to the Seaview Wastewater Treatment plant can be sent to the following contact details:
First point of contact: Veolia Duty Manager - Call 0800 928 371.
Veolia's Duty Manager contact number operates 24/7 as such complaints can be directly forwarded to them especially if the complaint is urgent and/or happened after office hours.
When a complaint is received, the following information will be recorded:
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Name
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Contact details of the customer
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Nature of the complaint
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Date and time
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Location
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Complaints shall be actioned within 24 hours upon receipt and the records being written to the plant's operational incident log. Odour and/or wastewater discharge complaints will be forwarded to the regional council.
Plant performance
Current status: Non-compliant
Period: October 2024
Commentary:
The plant remains non-compliant for faecal coliforms (90-day geomean, 80th percentile limit).
Discharges:
There was one consented discharge on 14 October of fully treated effluent to the Waiwhetu Stream due to wet weather.
Odour Complaints
The plant received 135 odour complaints in October. On three occasions GWRC deemed the odour Offensive and Objectionable.
Abatement Notice issued
GWRC issued a To-do Abatement ensuring odour treatment installation to the milliscreen and sludge dryer buildings by 1 December 2025. This second stage of the Odour Treatment Project will be delivered by the same project team that delivered the biofilter project in October.
Items of significance:
Increase in Odour
The increase in odour relates to mechanical failures with the sludge dryer and planned maintenance to the primary sedimentation tanks. The former resulted in biological process issues and solids buildup within the system. Work is ongoing to return the plant to normal operations with recent improvements to the process noted helping reduce the odour.
Odour Treatment Project – Stage 1 complete
The biofilter project to replace the “plenum” structure and upgrade cell isolation to improve odour management was completed in October, ahead of schedule.
What has been completed:
Stage 1 works to optimise the biofilter have been completed.
The procurement strategy for Stage 2 works (the milliscreening ducting replacement and building air treatment) is complete.
What is currently in progress:
Design activities for the milliscreening ducting replacement and building air treatment are nearing completion.
Implementation planning procurement strategy is underway.
Odour scouting in the community continues.
Resource consents
WGN050359 [24539] Discharge Treated Wastewater to Coastal Marine Area (Seaview WWTP)
WGN120142 [31740] Construction to Coastal Marine Area Maintenance (Seaview WWTP)
WGN120142 [33406] Discharge of Treated WW to Fresh Water Wet Weather (Seaview WWTP)
WGN120142 [33407] Discharge of Treated WW to Coastal Marine Area Maintenance (Seaview WWTP)
WGN120142 [33408] Discharge Treated Wastewater to Stream (Seaview WWTP)
WGN930193 [1] Contaminants Discharge to Air Outfall Structure (Seaview WWTP)
WGN930193 [2] Contaminants Discharge to Air Venting Structure (Seaview WWTP)
WGN950162 [1] Contaminants Discharge to Air WWTP (Seaview WWTP)
WGN930194 Land Occupation by Outfall Pipeline and Structures (Seaview WWTP)
Compliance reports
Seaview Wastewater Treatment Plant - 2021 2022 Compliance Report
Seaview Wastewater Treatment Plant - Consent Compliance Report 2022 - 2023
Seaview Wastewater Treatment Plant - Consent Compliance Report 2023 - 2024
Resource consent reports
Annual Reports:
Seaview Wastewater Treatment Plant Annual Resource Consents Report 2023-24
Seaview Wastewater Treatment Plant Annual Resource Consents Report 2020/2021
Seaview Wastewater Treatment Plant and HCC/UHCC Trunk Main Annual Resource Consents Report 2019/2020
Seaview Wastewater Treatment Plant Annual Report 2021/2022
Seaview WWTP 2022/ 23 Annual Consents Report
Quarterly Reports:
Seaview Wastewater Treatment Plant July - September 2024 - Quarterly Resource Consents Report
Seaview Wastewater Treatment Plant January March 2023 Quarterly Resource Consents Report
Appendices:
Seaview Wastewater Treatment Plant Annual Consents Report 2023-24 - Appendix ||| Trade Waste
Public health statements on the use of the treatment plant odour neutraliser
Summary
Potential health concerns associated with exposure to quaternary ammonium compounds are most likely associated with direct contact with undiluted product i.e. the staff preparing the solution. Staff exposure risk is managed by following the correct health and safety procedures. Quaternary ammonium compounds are often part of household cleaning and disinfection products and so exposure to the public is relatively common. Given the level of dilution of the product used in the cannon, and the distance between the placement of the cannon and potential locations for public exposure (typically this type of cannon dispersal method has an estimated droplet range of 50-100 metres) that effectively dilutes the strength further, we would not expect this to represent a health risk for the general public.
Te Whatu Ora - Health NZ - April 2023
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In May 2024, The plant operator, Veolia, switched to a new product Odour Neutraliser Plus (SCD1100) which is manufactured by biOx Environmental. This is a stabilised chlorine dioxide product that oxidises odour molecules such as Hydrogen Sulfide. The product is safe when used as directed and is utilised in wastewater treatment plants, landfills and transfer stations throughout New Zealand. While the previous product Hi Chem Disinfectant Reodorant presented no public health risks (see above) we decided to act on complaints from the community about the odour it generates and changed to Odour Neutraliser Plus (SCD1100). More information about this product