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Knowledge Hub / The Network / Wastewater / Wastewater treatment plants / Porirua Wastewater Treatment Plant

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 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 2023 - 2024

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

 

GWRC Compliance Reports:

Porirua Wastewater Treatment Plant, GWRC Compliance Monitoring Report 2023-2024

Porirua Wastewater Treatment Plant, GWRC Compliance Monitoring Report 2022 - 2023

 

Quarterly Reports:

Porirua Wastewater Treatment Plant July - September 2024 - Quarterly Resource Consents Report

Porirua Wastewater Treatment Plant April - June 2024 - Quarterly Resource Consents Report

Porirua Wastewater Treatment Plant January - March 2024 Quarterly Resource Consents Report 

Porirua Wastewater Treatment Plant July - September 2023 Quarterly Resource Consents Report 

Porirua Wastewater Treatment Plant October - December 2023 Quarterly Resource Consents Report 

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: October 2024

Commentary

The plant is compliant for effluent quality.

Discharges

No discharges in October.

 Odour and Discharge Complaints

No odour complaints in October.

Items of significance:

UV Performance Issues

The project team continue to monitor the UV system to improve system resilience. The UV manufacturer is supporting this process. Changes made to date have improved UV performance during high volume flows. Additional monitoring is in place to identify the intermittent fault, and the system will continue to be closely monitored. 

 

Advisory Notice and Formal Warnings issued

GWRC issued an Advisory Notice relating to the UV system issues with required actions by selected dates to ensure the corrective changes are implemented to mitigate further discharges. Two Formal Warnings were issued relating to undisinfected discharges that occurred on 16 and 17 June 2024. 

Odour Survey Reports

Complaints

Complaints Procedure

Complaints to the Porirua Wastewater Treatment plant can be sent to the following contact details:

Veolia Duty Manager (First Point of Contact): 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.

Wellington Water: Call 04 912 4470 or email customer@wellingtonwater.co.nz.

When a complaint is made, the following information will be recorded: 

    • Name 

    • Contact details of the customer 

    • Nature of the complaint 

    • Date and time 

    • Location 

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.


Complaints Register

Odour Complaints

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

24/02/2024

24/02/2024 – 9:38 am  

We received a formal complaint letter from one of the Pikarere farm resident relating to odour.

NW

31.3

OFF

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

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

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

15/12/2023

15/12/2023 -16:21 pm

Sewer smell bad again

NW

47.3

OFF

Normal

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

5/11/2023 -9.55pm

5/11/2023 - 9.55pm

Smell

NW

20.8

Off (00:00 to 23:06)
On (23:07 to 23:59)

Normal

1/11/2023

1/11/2023

Smell 

NNW

16

Off

Normal

1/11/2023

31/10/2023

Smell

ESE

18.2

On (0:00 to 4:58) 
Off (4:59 to 23:59)

Normal

1/11/2023

18/10/2023

Smell

SE (0:00 to 8:35)
NW (8:36 to 23:59)

15.1

On (0:00 to 8:35) 
Off (8:36 to 23:59)

Normal

1/11/2023

14/10/2023

Smell

NW

45.6

Off

Normal

1/11/2023

13/10/2023

Smell

NW

32.9

Off

Normal

Wastewater Discharge Complaints

Date of Complaint reviewed by Wellington Water

Date of Incident

Complaint description/ Characteristics as per the complainant

Duration of the alleged event/incident

Location of the complaint

Cause of the complaint

Remedial actions undertaken

20/11/2024

18/11/2024

Smelly brown discharge that smells of sewage in Titahi Bay on Sunday 18 Nov 2024. The discharge outfall is frothy, smelly, and brown/discoloured.

Early morning and afternoon

Titahi Bay

N/A

N/A

26/08/2024

26/08/2024

Porirua Treatment Plant, Titahi Bay [notifier] called there is a wastewater discharge breaching the consent. Customer also emailed in the complaint.

N/A

Titahi Bay catchment site

Investigation has been undertaken and confirmed that there was no discharge. Regional council has been informed with the outcome of the investigation.

N/A

10/04/2024

7/04/2024

On 7/04/2024, the complainant emailed Greater Wellington Regional Council regarding sewage from possibly Porirua Wastewater Treatment Plant going into the ocean near Rukutane point using the FB post uploaded on the Titahi Bay Residents Associations page as reference.

The complaint indicated that there would have been another discharge incident on 7 April 2024. This is still under investigation.

Lodged via Titahi Bay Residents Association's Facebook

Visible discolouration around the coastal marine area and cause is still under investigation.

Investigations underway to determine the cause.

10/04/2024

6/04/2024

On 9/04/2024 at 6.20 pm, a formal complaint was lodged to Greater Wellington Regional Council. The formal complaint was lodged for the discharge captured through video for the discharge that occurred on Saturday 6 April 2024 from the Treatment Plant outlet pipe (600m from Titahi Bay beach).

The discharge started at 2.17pm and lasted for approximately 2 hours and 21 minutes.

Titahi Bay catchment site

Visible discolouration around the coastal marine area and cause is still under investigation.

Investigations underway  to determine the cause.

12/04/2024

12/04/2024

On 12/04/2024 at 4.49pm, Wellington Water received notification about a public complaint regarding visible discoloration noticed at Porirua Wastewater Treatment Plant. 

The discharge started on at 3.18pm which is still under investigation.

Location details are withheld to avoid a privacy breach. 

Visible discoloration around the coastal marine area and cause is still under investigation.

Investigations underway to determine the cause.

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

Porirua Wastewater Treatment Plant Monitoring and Management Plan

Community Liaison Group (CLG) Meeting Minutes