Tri-partisan project boosting water security

One of the largest water security projects ever undertaken in the North West region of New South Wales has been completed, with the 8000ML Quipolly Dam now connected to the taps of residents in Quirindi and Werris Creek through a new $36.9 million water treatment plant and pipeline.

New South Wales Department of Climate Change, Energy, the Environment and Water Executive (DCCEEW) Director of Infrastructure Development, Lisa Hingerty, said crossing the finishing line is a huge achievement for everyone involved in the project over the long period of time, from early design to planning, to construction.

“The original pipe that runs from Quipolly Dam to the treatment plant at Werris Creek was built at the start of the last century, while the plant itself dates back to the 1930s and had reached its use-by date, which is why all three levels of government made replacing them a key priority,” Ms Hingerty said.

Pumping technology

The centrepiece of the new infrastructure is the state-of- the-art water treatment plant near Quipolly Dam which can produce up to six million litres of high-quality water every day to cater for population growth and tourism.

The treatment facility has seven primary treatment processes, including powder activated carbon, coagulation/ flocculation, dissolved air flotation, ozone, BAC filtration, UV light and chlorination to address the massive and sustained blue green algae blooms experienced in Quipolly Dam for much of the year.

There are a total of 37 pumps involved in the project and all systems are monitored and controlled by a sophisticated Supervisory Control and Data Acquisition (SCADA) system which uses abnormal situation management protocols for displaying alarms.

Raw water pump station (RWPS)

The pump station consists of four Lowara NSCC 80-250 single stage horizontal centrifugal pumps (29L/s at 27m) flexible coupled with 11kW WEG motors. The raw water pump station draws water from a flooded offtake tower with five selectable levels within the dam and transfers it to the water treatment plant (WTP).

Each pump is fitted with a variable speed drive (VSD) and the number of pumps that operate, as well as speed settings, are determined by a set-point determined from the flow rate required by the WTP.

The RWPS operates between 26L/s and 87L/s. When the WTP is running at the 6ML/day capacity, three duty pumps operate in a first duty/second duty/third duty/standby arrangement, with room made for expansion to a fifth pump to accommodate a future capacity of 9ML/day.

Treated water pump station

This pump station involves three Lowara NSCC 65-250 single stage horizontal centrifugal pumps (43L/s at 83m) flexible coupled with 55kW WEG motors at the WTP, arranged in a duty/duty/standby configuration. Each pump is fitted with a VSD controlled by a target head from a discharge pressure transmitter.

The pumps draw water from the 2.5ML treated water supply tank and pump it to the existing North Quirindi and Werris Creek storage reservoirs for distribution in those town networks.

The pumped treated water flow is normally in the range of 25L/s to 100L/s, as controlled by the speed of the operating pump(s) to meet the filling requirements of the receiving reservoirs. The duty pumps adjust speed to maintain a set-point pressure in the common discharge pipe. Operators can select which pump is to be the duty or standby pump via SCADA.

Filter backwash pumps

Two Lowara NSCC 250-315 single stage horizontal centrifugal pumps (175L/s at 9.4m) flexible coupled with 22kW WEG motors are utilised for backwashing the two filters in the WTP. The pumps operate on duty/standby and provide both low (50L/s) and high (170L/s) rate backwash flows.

Various sludge pumps

Horizontal progressive cavity pumps (6L/s at 50m) for thickened sludge transfer and submersible guide rail mounted pumps (9.6L/s at 6m) for sludge feed to the sludge thickener manage sludge transfer.

Process and dosing pumps

Various vertical multi-stage centrifugal pumps supply water for the treatment process, wash down, recycling and cooling purposes. Outputs range from 0.9L/s to 17.5L/s. Additionally, numerous Prominent chemical dosing pumps form part of the system.

Most of the pumps are single stage horizontal centrifugal pumps flexible coupled with WEG motors and constructed from cast iron casing. The multistage pumps are stainless steel construction and have integral VSD controllers mounted on them. The dose pumps were part of integral dose cabinets constructed offsite by Prominent and then installed to external pipework and electricity onsite.

All the pumps sit on a concrete plinth and were aligned onsite as part of their installations. Installation of the larger pumps involved a monorail and crane for easy pump and motor removal/installation.

Project challenges

Liverpool Plains Shire Council Water Services Manager, Rod Batterham, said that one of the biggest challenges the project faced was the effects of COVID-19 on the supply chain.
To overcome this, the project contractor was proactive in procuring items, such as pumps, early to make some allowance for the long lead in times.

“Pump selection in the design phase was also a challenge due to the large variance in flow rates required to fulfill the performance capacity currently, with consideration for future capacities. In most cases, pipework and other civil components was sized to suit the future capacity of 9ML/ day, but operational requirements currently needed to be between 2-6ML/day when servicing various combinations of supply to either, or both, Quirindi and Werris Creek water supplies,” Mr Batterham said.

Prior to construction and installation, Mr Batterham said commissioning of the pumps involved extensive Inspection Test Plans (ITP) for each individual pump, including mechanical, electrical and flow verification testing.

Boosting drought resilience

An official opening event for the project was held on Tuesday 21 May 2024 with local, state and federal dignitaries in attendance. Ms Hingerty said with construction now over, locals and visitors in Quirindi and Werris Creek can enjoy improved drought resilience, water quality and reliability for decades to come

“The new water treatment plant and transfer pipeline are equipped with all the latest bells and whistles to ensure the community has access to better quality water and more of it to meet the additional demand pressures caused by population growth and climate change.”

Liverpool Plains Shire Council is one of the first water utilities in regional New South Wales to use the cutting-edge Hydroplus Fuse Gate spillway system that helps safeguard water infrastructure during flood events and enables the plant to capture and store flood water.

Despite construction of the new plant commencing in late 2021, the entire project has been almost two decades in the making. The completion of the Quipolly Water Project marks the final stage of Liverpool Plains Shire Council’s long-term water vision, known as the Regional Water Supply Strategy.

Funding facilitating future projects

The Quipolly Water Project was funded with the help of the New South Wales Government’s Safe and Secure Water Program which is supporting more than $1 billion worth of projects across the state, with over 260 in various stages of delivery.

This program replaces and upgrades at-risk water and sewerage infrastructure to improve town water quality, reliability and wastewater services right across the state ensuring regional communities are ready for the future.

In a changing climate and with another drought already on the doorstep for parts of the state, investing in clean drinking water has never been more important and the New South Wales Government is continuing to work with local councils and communities to deliver the infrastructure that is needed.

Featured image: The state-of-the-art water treatment plant near Quipolly Dam. Image: NSW Department of Climate Change, Energy, the Environment and Water