Contract - CN000109.

W0988 Merrimu WFP – Fluoride Upgrade

Western Water is intending to release a Request for Tender for the detailed design and construction of a sodium fluoride dosing system (bulk powder) at its Water Filtration Plant (WFP) at Merrimu, Victoria.

The design capacity of the WFP is 8 ML/d minimum and 30 ML/d maximum production rate. Engineering Functional Design was developed in mid-2019 as a basis for the detailed design and construction. The functional design was developed in sufficient detail to:

• Confirm the space, arrangement, equipment requirements and interfaces with the existing plant
• Develop the Scope of Work for implementation through a D&C Contract
• Enable the preparation of a cost estimate
• Identify key project risks and opportunities

 The Merrimu WFP sodium fluoride system upgrade comprises the following elements:

• New fluoridation plant building, including a new electrical switchroom
• New sodium fluoride upflow saturator and day tank
• New sodium fluoride transfer pumps and dosing pumps
• New sodium fluoride dosing lines and injection point
• Modification to the existing treated water pipework to the Clear Water Storage tanks
• Modification to the existing service water supply pipework and new water softener
• New waste transfer pump and waste collection tank
• New safety showers (including eye wash stations) and service water hose reels
• New background (raw water) fluoride analyser
• New sample line to the existing treated water fluoride analyser
• New CWS feed flow meter
• Electrical and control system integration works
• New suction pipework to the Toolern Vale pumps
• New pipework to allow the 5ML Treated Water tank to be drained and diverted to Djerriwarrh Reservoir
• Modifications to the existing site road for chemical delivery and pedestrian access
• A new Allen Bradley MicroLogix 1400 PLC system. The new PLC will have an ethernet connection to the existing SCADA network switch located in PLC Panel within control room 2. The connection shall be fibre optic between buildings.

The equipment and modes of operation must comply with applicable Western Water standards, the Code of Practice for Fluoridation of Drinking Water Supplies, 2018 and any other relevant industry-wide standards.

While the functional design forms the basis for the detailed design, Western Water allows flexibility for tenderers to develop their offers based on their proprietary equipment and offer more cost-effective solutions. Potential for reductions in building footprint and height have been identified. Functional design specifies features and performance requirements, but allows room for alternative design by the D&C contractor, which may achieve the specification requirements, while offering savings. Early engagement between Western Water and the D&C contractors during the tender period is welcomed in order to explore opportunities for optimisation.

The detailed design, that will be developed by the selected Contractor, will be sent for review and approval by the Department of Health and Human Services (DHHS) to confirm compliance with the Code of Practice for Fluoridation of Drinking Water Supplies, 2018 before Construction begins. The DHHS approval process is anticipated to take several months.

Industry briefings and a site visit will occur one week after tender publishing. Questions during the tender period are encouraged and can be directed via the official tender publication on the Tenders VIC website.  

The contract will be delivered under a D&C model to AS4300. It is expected that tenderers would be able to demonstrate previous experience with design and construction of fluoride dosing systems, and have availability to complete the works within the required timeframe.