The Mareeba Wastewater Treatment Plant Upgrade project is funded through a $6 million grant from the Australian Government’s National Stronger Regions Fund, a $1.5 million grant from the Queensland Government’s Building our Regions program, with the remainder funded by Mareeba Shire Council.

Downer Utilities Australia Pty Ltd were awarded the contract for the design and construction of the Mareeba Wastewater Treatment Plant in late 2015.

The new Mareeba Wastewater Treatment Plant is a dual basin Sequence Batch Reactor (SBR) system designed to treat up to 3.8 ML/day dry weather flow and up to 10.6 ML/day peak wet weather flow. The system is an activated sludge process providing biological nutrient removal. The effluent from the SBR flows to a polishing clarifier and a chlorine contact tank before being discharged to the nearby creek.

A brief description of the project scope of works is as follows:

  • A new dual basin SBR-type bioreactor (each 33 m long x 13 m wide x 6m), each with a 9 m decanter.
  • Three new bioreactor aeration blowers, and two aerobic digester blowers and a compressed air system in a blower building.
  • Re-use of the existing secondary clarifier for treated effluent suspended solids polishing.
  • A new chlorine contact tank with inclusion of a de-chlorination chamber.
  • New service water system, drawing from the chlorine contact tank.
  • New chemical dosing systems for alum, caustic, liquid sugar, sodium hypochlorite and sodium metabisulphite.
  • A new aerobic digester (diffused aeration and supernatant off take).
  • New dewatering system, comprising liquid polymer dosing and belt press.
  • New switch room and switchboards.
  • New amenities buildings.
  • New standby generator.

Construction is approximately 75% complete with the majority of civil and concrete construction work now finished.  Testing and commissioning is due to commence in April 2017, with the plant scheduled to be handed over to Council’s operators by the end of June 2017.

The upgraded Wastewater Treatment Plant will provide for the current population and into the future whilst also providing significant environmental benefits for the receiving waters of Two Mile Creek; a tributary of the Mitchell catchment. The new treatment plant will have a capacity of 12,500 equivalent persons and allows for future expansion to increase the plant’s capacity to 16,500 equivalent persons.

21 December 2016 – Aerial photograph of SBR construction with old plant in background
21 December 2016 – Overall site aerial photograph
16 January 2017 – Admin, MCC, Blower and Biosolids Dewatering Buildings
16 January 2017 – Downer’s Project Manager and MSC Manager W&W inspect the SBR construction
21 February 2017 – Aerial photograph of the project site
17 March 2017 - Installation of belt to sludge dewatering press
20 March 2017 – Decanter installed to SBR
10 April 2017 - Installation of pre-cast concrete panels to bioselector
26 May 2017 - Council staff witnessing diffuser bubble testing
26 May 2017 - Installation of road drainage
29 July 2017 - Official Opening
29 July 2017 - Official Opening