This page contains information about projects and work we are undertaking to improve the sewerage system in the district.
11/10/2018 2:20 p.m.
Since 2006, we have invested heavily in projects to address public concern about sewer spills into the harbour.
The programme of work includes:
- upgrading the wastewater treatment plant and wetlands,
- treating the spills at major sites
- replacing and repairing components of the sewer network to reduce spills.
We are also working with the Northland Regional Council and others to tackle wider harbour pollution issues.
Hikurangi Sewerage Network Upgrade
Council has progressed with the upgrade of one of the oldest sewer networks in the district, the system servicing the Hikurangi township.
The sewer system, comprising pump stations and 13km of pipe was built in the 1960's using clay and asbestos cement pipes.
A lot of the pipes are below the ground water table and when it rains, a lot of water enters the sewer system causing it to become overwhelmed with water.
In very heavy rain this can cause sewage to back up in the system and overflow through manholes or other exit points. It also means that some low lying properties cannot use their toilets for a period.
Council has looked at improving the system over the years, which has included a major upgrade of the treatment plant, however earlier work has had little impact on the effect of wet weather.
Through the 2015 Long Term Plan Council committed budget to upgrade the system in 3 stages. Stage 1, which was completed in 2017, involved replacing 1300 metres of deep and leaky sewer pipes, pump stations and rising mains.
By using pumps we can pump more water to the treatment plant reducing the chance of overflows.
Stages 2 and 3 are to remediate the gravity pipework to try and stop the water getting in in the first place.
Stage 2 is the highest priority works and stage 3 is the second priority. Stage 2 works is scheduled to start in 2018 with all works to be completed by 2020.
An overview of the project can be found in the presentation below.
Hikurangi Wastewater Upgrade.pdf
Hatea storage tank
During large storm events the Hatea pumping station on Whareora Road was discharging rain diluted sewage into the Hatea River.
To prevent this, an underground storage tank has been built next to the existing Hatea wastewater pumping station.
During storm events, when sewer pipes are full, the excess flow is diverted into the tank and stored. Once the storm has passed, the wastewater is pumped back into the sewer pipes to be treated at the main plant at Kioreroa Road.
The tank is sized to cope with most small storms and can store 1,000 cubic metres of wastewater. During larger storm events the wastewater is treated in the tank using ultraviolet light before being discharged into the Hatea River.
Work has been completed on a number of projects:
- Morningside flood relief drain
- Kamo Road sewer upgrade
- Kensington Avenue/SH1 sewer modifications
- Lupton Avenue sewer upgrade
- Waro rising main and pump station upgrade
- Relining of sewer network in Denby Crescent
- Five new public toilets constructed
- Upgrade of internal roads and administration building in the Whangarei WWTP
- Sewer extension on SH14 to service Maunu Road school
- Upgrade of telemetry systems so our pump station performance can be monitored eficiently and effectively 24/7
- Upgrades of ageing equipment at Whangarei WWTP
- Pump upgrades at some of our critical pumping stations
- Replacement of the Waverley Street rising main in Onerahi
- Digester upgrades at Kioreroa Road WWTP
- Wastewater overflow mitigation
If you would like further information about these projects, please contact us.