Treated Water Reservoir Vermin Proofing

Treated Water Reservoir Vermin Proofing at a Water Treatment Plant

Overview of Project:

A Water Quality Site Systems Audit Report highlighted the need to repair the existing vermin proofing on the Treated Water Reservoir as it was not fit for purpose. The chemical building on site also required Screens to prevent bugs inundating the facility.

Innovation:  In order to minimise the shutdown time required at the water treatment plant, Metal Maintenance will be pre-manufacturing all screens and components in our Gold Coast workshop prior to works commencing on site

Scope of Works:

Upon award of this contract Metal Maintenance will engage a RPEQ engineer to further develop the design drawings which will be submitted to the client prior to work commencing.  Measurements and specific information will need to be obtained following the award of tender.  

The design will be undertaken in accordance with the Engineering Design Review and Approval Procedure.  A Water Quality Project Management Plan will be developed in conjunction with the Water Quality Coordinator.

Metal Maintenance will develop an inspection, testing and commissioning plan to outline the works to be completed, the methodology and the inspection and test plans to be completed for the works. The plan will be issued for approval prior to works commencing.

Construction Activities:

  • Reservoir
    • There are 2x whirly-birds fitted to the metal roof of the reservoir that will require mesh screens installed with a 1mm nominal gap it is to be fitted between the roof and the reservoir.
    • Screens are to be retrofitted to the existing whirly-birds and ensure all gaps between whirly-birds, roof, and reservoir are sealed.  
    • A spare screen will also be supplied for future whirly birds.
    • Access to this roof will only be available through a boom lift as there is no safe anchor points fitted to the roof.
    • The existing galvanised wire will be removed.
    • Installation of the new vermin proofing will be undertaken in manageable sections to avoid any risk of contamination entering the reservoir.
    • The Treated Water Reservoir must be left secure (from a Drinking Water Quality perspective) whenever Metal Maintenance is away from the asset.
    • New sacrificial screen (so that it blows out in an overflow event) of 1 mm nominal aperture marine grade aluminium or 316 stainless steel construction will be installed over the existing mesh on the soffits.
    • All exposed ends of the roof sheeting will be filled in with aluminium fit for purpose.
    • All gaps around the reservoir will be rectified as best as possible.
    • External colour of any new flashing and screen frames will match the existing colour scheme of the Water Treatment Plant in the location that they are being installed.
  • Chemical Dosing Building
    • New stainless steel “ Invisi-gard “  insect screens will be fitted to the external surface of the windows to prevent unnecessary exposure to chemicals. (Technical Specifications attached)
    • Louvers will still be able to operate with the expected design.
    • Replace any existing missing or broken louvers.
    • Insect screens will have the capability to be removed for future cleaning.
    • The existing white fluorescent lights will be replaced with yellow fluorescent lights. (includes new starters)
    • An industrial clean will occur inside of the building to remove any remaining insects etc. from the floor and walls.

Materials & Cleaning Products:

All materials and equipment will be suitable for their intended use and fit for purpose.  The details and specifications of cleaning products will be provided to the client prior to use. Any material that becomes dislodged during the works will be removed and cleaned in accordance with the client’s procedures and relevant standards.  Timeframes will be arranged with operations to assist minimal disruption to the water treatment plant.

Reporting, Commissioning & Documentation:

Inspections will be undertaken during the works and upon completion of the project. Our quality assurance procedures will be utilised to ensure the agreed level of quality is delivered. All required commissioning documentation will be provided upon completion of the project.


Task was completed ahead of schedule and on budget.  In house fabrication of screens to house vermin proofing saved significant time and minimized shutdown time for the client.

The Client’s Project Manager contacted Metal Maintenance to compliment us on the standard of work that and design.  He also requested a budget figure to enable the client to include the vermin proofing design on other reservoirs.  The client was happy with the works completed.

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