WA – Dunsborough WWTP Chlorine Gas Upgrade

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WestWater won a tender with the Water Corporation for the Design, Supply, Installation and Commissioning of a pre-fabricated transportable chlorination building for the Dunsborough Wastewater Treatment Plant in the South-West of Western Australia.

The Dunsborough WWTP previously had sodium hypochlorite for disinfection of final plant effluent. Final effluent was used to irrigate an onsite woodlot during summer and was being discharged to the Station Gully drain during winter (as flows allow). Due to hypochlorite dosing pumping failures, the limited shelf life of hypochlorite, limited PLC control of the disinfection system and limited operational attendance to site, conversion to a gaseous chlorine disinfection system was required to improve disinfection system reliability at this site. This upgrade ensured the final effluent would comply with licence E-Coli requirements and reduce the risk of regulatory authority action.

The project comprised of:

  • Design and construction of a new Chlorination Plant, complete with all associated process, electrical and control equipment installed into a pre-fabricated transportable chlorination building.
  • Installation of a drum rail vacuum system with residual trim control to hold two 920kg chlorine gas cylinders, and complete with two chlorinators, two ejectors, sample pumps, a sample return system, emergency shutdown devices, as well as associated piping, valving and fittings.
  • Installation of a potable water service tank (sized to allow for monthly re-filling) and includes an Electro-chlorination System.
  • Design and installation of a new drainage system to intercept and divert all overland stormwater flow around the chlorination module‚Äôs foundation, and direct it to the Station Gully Drain.