An overall planning programme for the Hervey Bay sewerage system considered a capacity upgrade at Pulgul Sewage Treatment Plant (STP).

Water Technology was commissioned by Wide Bay Water and Waste Services (WBW) to assess water quality implications concerning the Pulgul STP capacity upgrade works. This study built upon previous results Water Technology provided to WBW and included assessing the discharge from the existing Pulgul STP into Pulgul Creek and the relocation of the discharge to a location offshore of the Urangan marina.

Scope:

Assess the water quality implications concerning the Pulgul STP capacity upgrade works.

Location:

Hervey Bay Queensland

Client:

Wide Bay Water and Waste Services

Bathymetric data, wind and water conditions were sourced and applied to the Mike 3 flexible mesh model as tidal conditions, catchment inflows and wind forcing alongside the Pulgul STP discharge. Calibration took place through a controlled discharge from the Pulgul STP, allowing total nitrogen and total phosphorus levels to be measured and compared to model simulation.

Multiple discharge scenarios for the proposed site were considered and presented concerning water quality objectives as defined by the Environmental Protection (Water) Policy 2009. These were compared with the current water quality conditions associated with the existing discharge location. The most favourable results were identified for WBW. The application of a diffuser was recommended, and further modelling could apply diffuser specifications for improved results.

Key Services Provided