By Christopher Allan, Journalist, Pump Industry magazine
Completed capacity upgrade works, including a new aerator and installation of high-lift pumps, have revitalised the Ingham Depot Water Treatment Plant (WTP) as an evolving asset in local water security. We spoke to Hinchinbrook Shire Council to learn about the WTP upgrades, from procurement and the pump technologies utilised, to project completion and achieving community water security in the face of rain events.
Servicing the region surrounding Ingham in North Queensland, Hinchinbrook Shire Council has traditionally supplied potable water from two main sources: underground bores in the Como Road Toobanna area, and treated water from the nearby Herbert River.
Yet during times of heavy rainfall and flooding of the Herbert River, water quality emerged as an issue for both Council and the local community, due to the highly turbid nature of the river system.
Hinchinbrook Shire Council Mayor, Ramon Jayo, said, “When the water in the river is of poor quality, the pumping station is turned off and water is only drawn from bore systems around the shire. Those bores have historically been inadequate to fully meet the Ingham and surrounding area’s water demands.”
A recently completed project to refurbish the Ingham Depot WTP has risen to the challenge of local water security and ensured a stable role for the Herbert River as a key water supply.
The major upgrade works of the project included new raw water delivery infrastructure, a new aerator and high-lift pumps, as well as the design and construction of new bores.
The project was taken on by Hinchinbrook Shire Council in a jointly funded project with the Queensland Government’s Building Our Regions (BoR) program, with Council receiving $2 million in funding from Round Three of the BoR program for a $4.4 million project that created 13 jobs.
Project beginnings: upgrade selection and procurement
Finding the right upgrade pathway
A review of systems uncovered three upgrade pathways for Hinchinbrook Shire Council to address the challenge of stable water access for the Ingham region. The review allowed Hinchinbrook to:
- Investigate all the options to deliver a sustainable clean water supply including consideration of a suitable treatment system
- Assess the priority and affordability of options including a preliminary evaluation of the costs, risks and benefits including preliminary estimates for operations, maintenance and ongoing costs
The three upgrade pathways investigated by Council were:
- Option One: Implementation of a water filtration treatment plant for the Herbert River water source
- Option Two: Duplication of the Como Road Bore Field and Ingham Depot WTP augmentation
- Option Three: Development of bores near the Herbert River Intake
Utilities Services Manager, Peter Martin, explained, “Capital and operational costs associated with Option One and Two were determined, which identified a similar capital cost on a dollar per megalitre basis.
“Ultimately, Council identified Option Two – Duplication of the Como Road Bore Field and Ingham Depot WTP augmentation – as the preferred upgrade pathway, noting its advantageous annual operational cost.
“As Hinchinbrook Shire is a smaller council, with staffing resources not always available to complete repairs, Council deliberately involved asset maintenance staff to confirm that the package of upgraded equipment could be affordably serviced and replaced.
“As equipment was part of the whole tender package, the evaluation was reviewed by the Council staff that would need to maintain this equipment over its lifetime.
“Equipment was confirmed to ensure that they met design criteria, availability of spare parts and servicing, and regional service agents who could assist in the maintenance of these units in the future if required.”
The Ingham Water Plant upgrade project was tendered out as two packages: the Treatment Plant upgrade, and the installation of associated pipelines.
Peter Martin explained, “The treatment plant package included the supply and installation of new high-lift pumps – two 120L/sec pumps and one 60L/sec pump – as well as the supply of new bore pumps capable of delivering 60L/sec back to the treatment plant.
“As this was a duplication process, the aerator was a copy of the existing one already on site. Consulting engineers, GHD, completed the design and tender packages for the project, as well as provided project management. Electrical and chemical dosing upgrades were also scoped as part of the Treatment Plant upgrade package.”
Project delivery: infrastructure, challenges, community impact
Key project infrastructure delivered
The scope of process, civil, mechanical and structural work carried out under the Ingham WTP contract included the following:
- Fit out of a newly constructed water supply bore (construction of bore and casing to be completed by subcontractors) including modular submersible bore pump of 316 stainless steel (SS) construction complete with flexible riser, 316 SS safety cable, power supply cabling, level probe, integral nonreturn valve and break-off plug
- Upgrade of the WTP capacity, including DN250 DICL raw water supply pipework from new pipeline interfacing point at WTP
- Modification of the existing aerator sump to increase the height by 400mm
- New duplicate cascade aerator to match the existing aerator
- New pump out well and connection pipeline between the existing reservoir and new reservoir to allow for pumping out and/or isolation of a reservoir
- Three new pumps, including: single 60 litres/second (L/s) high-lift pump and two 120L/s variable speed drive (VSD) controlled high-lift pumps
- New recirculation pump (40L/s) to supply recirculation water to both aerators
- Supply, installation, testing, calibration and commissioning of new treated water sampling and dosing pump controllers
- Electrical switchboard, controls and telemetry elevated above flood level underneath a proprietary shade structure
- Connection to Ergon Energy power supply at adjacent power pole (provided by subcontractors)
- New inline concrete chemical dosing and distribution well
- New treated water storage lagoon with high density polyethylene (HDPE) liner and floating cover of approximate capacity of 1.5ML
- Replacement of floating liner on existing lagoon
- Upgrade of existing power supply (by Ergon Energy) and installation of new switchgear to suit Depot and WTP supply
- Replacement of existing WTP switchgear to suit the new WTP upgrades
- Replacement of existing telemetry system with radio and Programmable Logic Controller (PLC) configuration for remote control of WTP
Success despite operational challenges
The success of the WTP upgrade project comes despite a central challenge of maintaining operation of the existing plant. Mayor, Ramon Jayo, advised, “The major challenge with the WTP upgrade was that the existing plant had to be operational for as long as possible while construction of the majority of the new works were undertaken.
“The contractor’s schedule of works meant that a planned shutdown of the whole site was limited to only three or four days to allow for connections to existing tanks, pipelines and structures where the plant could not supply water to the system.”
The success of the upgrade despite operational challenges speaks to the dutiful design approach of the project’s consulting engineers, GHD.
“GHD’s design process incorporates relevant Safety in Design (SiD) processes, which will consider construction interface risk, including minimisation of changeover and commissioning of new infrastructure with existing, operational infrastructure.
“This design process involves the identification of key risks and adopting design principles to address such risk,” said Peter Martin.
Further challenges encountered on the Ingham WTP project included finalising permits for pipelines in the Main Roads corridor, especially in finalising the design of the raw water pipeline crossing the main highway coming into Ingham. However, collaboration between GHD, contractors and the Main Roads team ensured a successful outcome.
Community sees success across security and capacity
Prior to refurbishment of the Ingham Depot Water Treatment Plant, flooding and run-off events that compromised the water quality of the nearby Herbert River would severely limit community water access to an inadequate network of bores.
The refurbished plant allows treated water from the Herbert River to play a more stable role in local water security, alongside the newly upgraded network of bores. The upgrades will also deliver a boosted production capacity for the Ingham community.
Mayor, Ramon Jayo, informed that “Hinchinbrook Shire will have its potable water secured for the next 20 years with the construction of new bores and a raw water pipeline connecting to the existing network, to supply an additional 2.2ML/day to the Ingham Depot WTP.
“In combination with augmentation at the WTP, the total production capacity will reach 5.2ML/day.”
From selecting the best upgrade pathway and equipment, to working closely with the project’s consulting designers to ensure continued operation during construction, Hinchinbrook Shire Council has delivered a critical asset for water security in the local community, come rain or shine.