Graduated trash rack GPT under construction
05 · Case Studies

Proof, not promises — GPTs designed, built and rescued.

Two projects delivered for Logan City Council: a full GPT design-and-construct, and a complex rectification of a failed custom unit. Both show the engineering depth and delivery capability behind the RenewQEST partnership.

RSN23377 DESIGN & CONSTRUCT CITY OF LOGAN

Woodridge Adventure Park GPT

173 Kingston Rd, Woodridge, QLD

A complete design-and-construct of a graduated trash-rack stormwater treatment system — from RPEQ-certified engineering design through to constructed asset. Renew coordinated the design; QEST-style civil delivery executed the build.

Rigorous QA underpinned every stage: subbase density (compaction) testing, concrete strength and thickness testing, non-destructive concrete scanning to verify reinforcement, and staged trash-rack inspections — all documented and RPEQ-signed.

Completed graduated trash-rack screen along the channel
GRADUATED TRASH RACK · COMPLETED
Design
RPEQ-certified civil & structural, incl. wing-wall reinforcement
Testing
Compaction, concrete strength & thickness, concrete scanning
Inspections
Staged trash-rack inspections across the build
Reinstatement
Sandstone headwall, footpath & turf reinstated
Installed graduated trash-rack screen, front view Completed GPT with sandstone headwall Completed asset with rock rip-rap and reinstated fencing
RSN21927 COMPLEX RECTIFICATION LOGAN CITY COUNCIL
Inside a damaged Ecosol GPT
ECOSOL GPT 4450 · ASSET SE195

152 Haig Road GPT rescue

Loganlea, QLD · Apr–May 2022

A custom Ecosol GPT 4450 was found with major damage to its internal steel filtration screens — the result of a non-standard design and poor installation. Inlet and outlet pipes sat at base-slab level (rather than ~900 mm above), starving the unit of bypass and blowing out the steel internals under hydraulic load. A mass concrete pour had blocked maintenance access, and access covers sat non-compliant in a pedestrian footpath — an OH&S hazard.

Renew isolated and rebuilt the asset to a compliant, serviceable standard.

Rectification works
01 · Expose

Site isolated with temporary fencing and pedestrian diversion; footpath and mass concrete pour demolished down to the cover slab; slab lifted to expose the blown-out steel internals.

02 · Refurbish

Vacuum-cleaned and stripped; steel internals workshop-refurbished with extra vertical supports, new oyster-mesh screens, structural weirs to direct low flows, and reinforcing angles against hydraulic blow-out.

03 · Reinstate

Internals re-secured with Trubolts, penetrations rendered and sealed, cover slab and concrete risers recast, genuine Ecosol cast-iron covers & frames fitted, footpath and turf reinstated.

Before · failed & non-compliant
Failed cover slab and exposed chamber before rectification Blocked outlet and debris in the GPT internals
During · isolate, rebuild & recast
Cover slab lifted out to expose the chamber Structural support brackets fitted to the chamber walls Reinforcement mesh and access covers set before the pour Refurbished stainless-steel filtration screen internals New screen basket installed and sealed into the chamber Installed filtration screens and baffles, top view
Completed · compliant & serviceable
Completed access slab with compliant cast-iron covers Reinstated site with turf and compliant access covers
Why it matters for Geelong

These are exactly the failures a routine, transparent maintenance program catches early — before a GPT stops working and a council carries the risk.

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