Porirua Wastewater Treatment Plant
At the Porirua Treatment Plant, sewage travels through a series of screens, bioreactors, clarifiers and ultraviolet treatments before being discharged as liquid into Rukutane Point.
For more information on how wastewater is treated, go to the treatment process.
The consent for the Porirua Wastewater Treatment Plant (WWTP) was recently renewed.
In general, the consents allow Porirua City Council to:
- discharge treated and partially treated effluent at Rukutane Point through an existing outfall,
- discharge contaminants to the air
- and permission to occupy the coastal marine area with a concrete deflection wall and outfall structure.
Upgrades to the plant’s UV treatment system and hydraulic capacity were completed in mid-2023. The plant is now able to treat a peak flow of 1,500 litres per second. In heavy rain the amount of wastewater delivered by the network can reach up to 1,300 litres per second.
Planning Ahead
Over coming decades, we want to keep reducing the volume and number of overflows from the wastewater network.
Overflows happen when rainwater overwhelms the wastewater pipe network, causing untreated wastewater to flow over land or into freshwater. This is objectionable, and abhorrent to mana whenua. Overflows contain bacteria that may make people sick if they come into contact with contaminated water.
We know where and when overflows happen from our monitoring, incidents reported by the community, and network modelling. Wellington Water and Porirua City Council have a view of where work is needed to reduce overflows and have already started on improvements. For example, the central wastewater storage tank will reduce overflows into Porirua Stream, and the Eastern Porirua regeneration project will reduce overflows into Kenepuru Stream.
Resource consents
Resource Consent Application 2020 - 2022
Independent Hearing Panel Decision Report (relating to the 2023 Resource Consent Applications: Renewal of existing consents for discharge of treated sewage to coastal water, and associated discharge to air from the Porirua Wastewater Treatment Plant)
WGN200229 [36816] Discharge to Coastal Marine Area (Porirua WWTP)
WGN200229 [36727] Contaminants Discharge to Air (Porirua WWTP)
WGN980083 [03] Land Occupation by Outfall Structure (Porirua WWTP)
Resource consent reports
Annual Reports:
Porirua Wastewater Treatment Plant Annual Resource Consents Report 2021/2022
Porirua Wastewater Treatment Plant 2020/2021 Annual Resource Consents Report
Porirua Wastewater Treatment Plant 2019/2020 Annual Resource Consents Report
Porirua Wastewater Treatment Plant 2018/2019 Annual Resource Consents Report\
Porirua Wastewater Treatment Plant FY22/23 Annual Resource Consents Report
Quarterly Reports:
Porirua Wastewater Treatment Plant October December 2022 Quarterly Resource Consents Report
Porirua Wastewater Treatment Plant July September 2022 Quarterly Resource Consents Report
Porirua Wastewater Treatment Plant April - June 2022 Quarterly Resource Consents Report
Porirua Wastewater Treatment Plant January - March 2021 Quarterly Resource Consents Report
Porirua Wastewater Treatment Plant October - December 2020 Quarterly Resource Consents Report
Porirua Wastewater Treatment Plant July - September 2020 Quarterly Resource Consents Report
Porirua Wastewater Treatment Plant April – June 2019 Quarterly Resource Consents Report
Porirua Wastewater Treatment Plant January March 2023 Quarterly Resource Consents Report
Plant performance
Current Status: Compliant
Period: December 2023
Commentary:
The plant is compliant for effluent quality consent limits.
Discharges:
There was one short duration discharge of biologically treated but undisinfected effluent on 8 December due to an unexpected power outage in the area. The power outage led to UV performance issues.
Please explain letter issued:
A response for the undisinfected discharge on 9 November was submitted to GWRC within the required timeframe.
Items of significance:
UV Performance Issues:
The project team continue to implement process modifications to fine tune the system's operation. To date this has proven successful during high flows. The system will continue to be monitored while these changes are being implemented.
The UV manufacturer reviewed several of the UV components in December also reviewing the system performance overall and will conduct further investigations in the new year.
More Documents Here
Cawthron Institute Wastewater Treatment Plant Environmental Effects Assessment
Executive Summary - Porirua Wastewater Treatment Plant: Discharge of wastewater & discharge to air
Porirua Network Improvement Programme - Wastewater Overflow Reduction Master Plan Strategy November
Porirua Wastewater Network Improvements - Reports June 2021
Greater Wellington Regional Council Annual Compliance Monitoring Assessment
Incident Reports
Odour Control Best Practicable Option Review
Complaints Register
13 October - 5 November
|
Date of Complaint Submitted |
Date of Incident |
Complaint Description / Characteristics as per the complainant |
Wind Direction |
Ave Windspeed (km/h) |
Inlet Tunnel Vent Fan Operation |
Plant Operations |
|
1/11/2023 22:09 |
13/10/2023 |
Musty Smell |
NW |
32.9 |
Off |
Normal |
|
1/11/2023 22:09 |
14/10/2023 |
Musty Smell |
NW |
45.6 |
Off |
Normal |
|
1/11/2023 22:09 |
18/10/2023 |
Musty Smell |
SE (00:00 to 8:35) |
15.1 |
On (00:00 to 8:35) |
Normal |
|
1/11/2023 22:09 |
31/10/2023 |
poo smell |
ESE |
18.2 |
On (00:00 to 4:58) |
Normal |
|
1/11/2023 22:09 |
1/11/2023 |
musty smell |
NNW |
16 |
Off |
Normal |
|
5/11/2023 21:55 |
5/11/2023 21:55 |
the plant smell is now worse it used to be a musty smell it’s now got a poo smell |
NW |
20.8 |
Off (00:00 to 23:06) |
Normal |
14 December - 19 January
|
Date of Complaint Submitted |
Date of Incident |
Complaint description/ Characteristics as per the complainant |
Wind Direction |
Average Wind speed (Km/Hr) |
Inlet Tunnel Vent Fan Operation – 24 hr format |
Plant Operations |
|
14/12/2023 |
14/12/2023 – 20:30 pm |
Complainant could smell plant up at his house . Requested the odour assessor to perform assessments in the evening |
NW |
34.9 |
OFF |
Normal |
|
15/12/2023 |
15/12/2023 -16:21 pm |
Sewer smell bad again |
NW |
47.3 |
OFF |
Normal |
|
03/01/2024 |
03/01/2024 – 23:01 pm |
last 2 months has been the smelliest the Tītahi Bay sewer treatment plant has ever been mainly in the evenings .Tonight was really bad up at my house and 3 nights ago I called Veolia and requested that the tunnel fan be turned off the smell was terrible I don’t know what’s going on down there but the smell is the worst it’s ever been. I understand you have things in future for odour mitigation but I’m not willing to wait I think it is in order to get a mist deodorising machine working immediately. The rules clearly state no objectionable odour to cross the boundary and it is right up to my house please come back to me with the solution please. |
NW |
23.9 |
OFF |
Normal |
|
08/01/2024 |
08/01/2024 – 12:19 pm |
Have just been to the front gate of the farm and the smell of sewage ( human waste) is very strong and frankly unacceptable. Lately in northerly conditions there has been strong odour. What controls are on the fan which I believe is the source of the odour ? Does it turn off automatically as proposed in the Update Memo at the meeting at Porirua on26 October. Please let me know what action is currently being taken as the odour/smell is unacceptable and clearly in breach of the conditions of the resource consent. Please treat this email as a formal complaint to be recorded in the complaints register |
NW |
24.4 |
OFF : (01:05 – 23:59)
ON : (00.00 - 01:04) |
Normal |
|
18/01/2024 |
18/01/2024 -20:47pm |
I would like to know what is been done about the odour at the plant I haven’t heard back what the plan is but tonight smells bad last night also and Sunday and Monday. |
NW |
16.1 |
OFF : (00.00 – 00:36) , (05:00- 23:59) ON : (00:37-04:59) |
Normal |