Brolton Group partnered with Ventia and Sydney Water to refurbish Clarifier No 2 at Glenfield WRP

System Benefits

  • 25% plant throughput
  • 100% plant uptime
  • 10 years extended life

The clarifier at Glenfield WRP was out of service due to blockage of the scum drain and was due for maintenance.  As it was not in operation, there was increased load on other items of plant.  There was also significant corrosion of metal components as a result of galvanic corrosion caused by inadequate use of isolation. If left unaddressed, this would continue to deteriorate and affect the operating efficiency of the plant, potentially causing major damage to the rotating equipment.

By overhauling the equipment there would be a significant improvement in the efficiency of the plant which would ensure the ability of the plant to meet future demand and allow isolation of other clarifiers if required. There would also be a saving in future equipment repair and the associated coordination involved in bypassing failed equipment. The works carried out also reduced the risk of personal injury while maintaining items of plant and reduced the risk of damage caused by plant failure.

The work was carried out in three phases.

Phase 1

Isolations and general cleanout were provided by the Sydney Water site team.

At this time the clarifier was deemed a confined space work and precautions had to be taken to ensure safe entry once the Clarifier was emptied.

Scaffolding was introduced to the site for access into the tank which removed the confined space state.

Phase 2 

Once the Clarifier was emptied and safe to work in, the repairs and remediation works took place. 

These works included:

  • Cleaning all internals of the Clarifier
  • Addressing degradation of concrete surfaces and joints throughout the tank including, floor and wall seals
  • Removal of all clarifier components for blast and paint
  • Abrasive blasting and repainting all clarifier components including, Bridge & handrail, centre column, scraper rake arm, trusses and scraper drum
  • Site patch repair of baffle plate connection brackets
  • Replacement of all under-baffle plates with Stainless steel equivalents
  • Rectifying leaks on inlet channel
  • Replacing drive & idler wheels, slip rings and bearings on centre column
  • Refurbishing motor and gearbox
  • Replacing scum beach and box with stainless steel
  • Restoring operation to blocked scum beach drain
  • Replacing failed manifold seals on sludge rake arm
  • Replacing rubber scraper blades
  • Addressing corrosion issues across the clarifier
  • Develop test plans
  • Complete testing of clarifier and check off
  • Dry run clarifier and test
  • Wet run clarifier and test
  • Handover clarifier

 Phase 3 


  • Develop test plans
  • Complete testing of clarifier and check off
  • Dry run clarifier and test
  • Wet run clarifier and test
  • Handover clarifier

Solution Overview

Brolton Group were engaged by Ventia on behalf of Sydney Water to complete an overhaul of the No.2 Clarifier at the Glenfield WTP. The purpose of the overhaul was to repair any corrosion and leaking issues of the clarifier that have occurred over its many years of service.

Brolton completed an entire clean of the clarifier components and tank which allowed close inspection of all items. After the clean, all the components were removed offsite for repair, blast and paint to Sydney Water specifications this process shall provide protection to the steel work for years to come.

During the offsite works, Brolton completed general works to repair the tank seals, cement work, and fixed steel components, this work overcame any leak issues with the tank. Upon completion of the offsite works all components were reinstated into the clarifier tank and assembled ready for testing.

Dry testing was completed with Brolton monitoring all movements, seal seats, and drive motion. Once dry testing was satisfied and checked off the clarifier was filled, wet tested and put back online.

Sydney Water Clarifier Project Brief (pdf 3.98 MB)

Case Study Topics: Engineering Mechanical Engineering and Fabrication Water and Waste Water

  • Clarifier 4
  • Clarifier 5
  • Clarifier 3
  • Clarifier 2
  • Clarifier 1
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