Young Sewage Treatment Plant Upgrade and Reclaimed Water Plant
The existing Trickling Filter Plant was replaced with a new 12,000 EP Sewage Treatment Plant while operational


The Young Sewage Treatment Plant (STP) was a Trickling Filter Plant (TFP) originally constructed in the mid-1930s and augmented in 1974. The effluent was stored in maturation ponds for tertiary polishing and then released to Burrangong Creek.

Leed replaced the existing TFP with a new 12,000 Equivalent Person STP based upon an intermittent decant extended aeration process (IDEA). Reuse water is treated to reclaimed standard and is used to irrigate public parks and fields that were previously supplied from the town's potable water.

The new STP was constructed while the exisiting TFP was operational. The TFP was then decommissioned and demolished to allow completion of the new STP and recycled water plant.


The project works included:


  • bulk earthworks
  • structures
  • process pipework
  • buildings and site works
  • all process plant works
  • all mechanical and electrical works
  • demolition of existing trickling filter plant
  • testing and commissioning.

Reclaimed water plant:

  • 3 ML storage/balance pond
  • UV unit (140 L/s)
  • lift pumping station (65 L/s)
  • chemical dosing facility
  • reclaimed water pump station (16 L/s)
  • reclaimed water buffer storage tank (291 kL).

Wastewater treatment plant:

  • inlet works (248 L/s)
  • two IDEA tanks (2 x 4000 m3)
  • Three sludge lagoons (3 x 3000 m3)
  • aluminium and caustic soda storage and dosing system
  • sludge dewatering (6 m3/hour)
  • supernatant pump station (35 L/s)
  • amenities building
  • control building.

Key features and challenges

This was the first project delivered for NSW Public Works under GC21 General Conditions of Contract.


Commissioning was smooth and successful, due to regular commissioning meetings with the Council's operator and the NSW Public Works design team.

The operation of the exisiting Sewage Treatment Plant was unaffected by the construction and commissioning of the new plant.

Cooperative contracting provided many opportunities for cost savings. For example, Leed's reuse of water during construction meant that Council did not have to supply clean water for the standard oxygen transfer rate test on the aerators.

“Council was able to maintain a good working relationship with the contractor throughout the project which ensured that when issues arose they were promptly dealt with in a cooperative manner in order to minimise time and cost impacts on the project for all parties.”

Nicole Vonarx, Engineering Director, Hilltops Council (formerly Young Shire Council), July 2015.

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