An industrial site in Geebung needed a wash bay to handle oily runoff and meet trade waste rules. The project called for concrete cutting, deep excavation, and a full pre-treatment system inside a working factory.
Citi Industries delivered a complete wash bay system that helped the Geebung site meet trade waste requirements.Â
Project Overview
The project sat inside a live factory, with tight access and existing services running beneath the wash bay footprint. Approximately 8 metres by 6 metres of concrete had to come out. In turn, the crew needed to work around the tenant’s daily operations without disrupting production. Additionally, the finished system had to satisfy Urban Utilities trade waste requirements and pass a council inspection before backfill.
Scope at a glance:
- Â 8m x 6m wash bay slab replacement in 32 MPa concrete
- 1200-litre holding tank with Class D sealed lid
- 1000-litre oil separator with diaphragm pump and control panel
- Â 250-litre sewer pump station on the outlet
- 20mm RPZD backflow valve on the cold water service
- 40mm pressure discharge line back to the sewer connection
Challenges
Wash bays produce water that carries oil, grease, and solids from equipment cleaning. This water is classed as trade waste under Queensland regulations, which means it cannot flow directly to the sewer. Instead, it must pass through a pre-treatment system that separates the hydrocarbons before discharge. The Geebung site added several complications on top of the standard rules.
Live services beneath the proposed footprint had to be identified before any excavation. Additionally, the client’s operations could not stop, which meant staged access and pedestrian control across the working site. Council also required inspection of the in-ground tanks and pipework before backfill could go ahead.
Specific constraints at the Geebung wash bay site included:
- Â Â Â Live production running throughout the works, with no shutdown windows
- Â Â Â Multiple existing services beneath the wash bay footprint
- Â Â Â Trade waste compliance under Urban Utilities acceptance standards
- Â Â Â Council inspection required before backfill of tanks and pipework
- Â Â Â Vehicle-rated finish needed for equipment traffic across the slab
The compliance plan drew from Urban Utilities trade waste approval and QBCC regulated plumbing work requirements.
Solutions
Citi Industries scoped and completed the full civil, plumbing, and electrical package on-site. Each deliverable is set out below.
Concrete Cutting and Site Preparation
The first task cleared the 8 metre by 6 metre wash bay zone. Citi Industries cut and removed the existing slab, then excavated for the tank pits and pipework. The team then compacted the affected areas before pouring the new slab.
Below-Ground Tank and Pipework Installation
A 1200-litre holding tank went in first, fitted with a Class D sealed lid rated for heavy vehicle traffic. The team then installed a 1000-litre oil separator with a diaphragm suction pump to remove hydrocarbons before the treated water entered the sewer system. Additionally, a 250-litre sewer pump station moves outlet water across to the factory’s sewer connection. The council inspected all in-ground works before backfill.
Venting to Atmosphere
Sealed trade waste systems must vent gases to the atmosphere to prevent pressure build-up therefore, Citi Industries installed an Air Admittance Valve, or AAV, at the oil separator outlet. A separate 100mm vent line runs off the holding tank and terminates outside the building.
Cold Water Supply and Backflow Protection
The wash bay needed a clean potable water supply and mandatory backflow protection. A Reduced Pressure Zone Device, or RPZD, prevents contaminated water flowing back into the mains supply. Citi Industries installed a 20mm RPZD on the cold water service and completed the council registration paperwork.
New Concrete Slab and Bund Edge
The finished slab measured 150mm thick and reached 32MPA strength for vehicle loading. The crew doweled single mesh reinforcement into the existing slab. They also formed a roll-over bund edge to contain runoff within the wash bay. Additionally, Citi Industries installed a 750mm x 750mm stormwater manhole lid and frame for the existing pit.
The plumbing and drainage scope meets the standards set out in the Business Queensland plumbing and drainage laws and codes.
Electrical and Control Panel
Every oil separator needs a control panel with alarm functions in case the water level rises above safe limits. Citi Industries wired in the suction pump, water level float, and alarm as part of the scope. As a result, the system flags issues before they escalate into spills.
Sewer Pump Discharge Line
The pump station needed a discharge line to the main sewer connection on the far side of the factory. A 40mm pressure line runs around the factory wall to that point. This routing kept the trench short and avoided crossing high-traffic zones inside the site.
Final Outcome
The site now operates a compliant wash bay from day one. It captures oily runoff at source, treats it on-site, and discharges cleanly to sewer. Facility staff can wash down plants and equipment during normal shifts without breaching trade waste conditions. This helps the operator meet trade waste requirements while reducing the risk of non-compliant discharge.
Key outcomes:
- Â Â Â Trade waste approval maintained through correct pre-treatment before sewer discharge
- Â Â Â Vehicle-rated slab and bund containment across the full wash bay footprint
- Â Â Â Alarmed control panel that flags separator issues before they escalate
- Â Â Â No disruption to factory production during the concrete cut, excavation, or install
Final Thoughts
A wash bay’s compliance does not end on the day the concrete cures. The oil separator, pump station, and alarm system must keep working long after handover. However, a rushed install tends to surface its faults early, through a failed inspection or a spill alarm.
Citi Industries completed the installation with long-term operation, maintenance and compliance in mind. A properly planned installation can also reduce the likelihood of callbacks, failed inspections and additional rectification work. The team reads the survey, works to plan, and satisfies council conditions before signing off.
So whether you are building a new wash bay or fixing a non-compliant one, talk to the team. The team can arrange a trade waste site assessment and provide the required documentation for council and trade waste approvals.Â
Call Citi Industries on 1300 002 484 to discuss your project.
1300 002 484
