Grease Trap Upgrade | Mt Gravatt, QLD

When grease traps fail in a busy retail environment, the consequences extend well beyond plumbing. Food court tenants face compliance deadlines, and centre management fields complaints about odours. As a result, every day of delay compounds the problem. A shopping centre in Mt Gravatt faced exactly this situation. Their ageing system could no longer handle wastewater volumes from multiple food tenants. Consequently, a full grease trap upgrade was required.

Why Citi Industries Was Brought In

Citi Industries was engaged to design and deliver the grease trap upgrade and sewer pump station replacement. The project required coordination across active retail operations. Additionally, strict adherence to Queensland Urban Utilities trade waste requirements was essential. Furthermore, the new infrastructure needed to meet both current and future demands.

Project Overview

The scope covered removal of the existing below-ground grease trap and sewer pump station. Additionally, it included installation of new compliant infrastructure and slab reinstatement. Importantly, the centre’s continuous operation was a key constraint. Work areas sat adjacent to high-traffic pedestrian zones. Therefore, food tenants required minimal disruption to their trading hours.

The project delivered:

2,000-litre Halgan below-ground grease trap with Class D vehicular-rated lids
1,200-litre REEFE dual sewer pump station with controller and high-level alarm
100mm atmospheric vents for all wastewater components
20mm RPZD backflow valve on washdown tap
Full decommissioning of existing tanks with lime treatment and backfill
Concrete replacement across all affected areas
Pedestrian barricading throughout the works

Challenges

Grease traps at commercial food premises must satisfy requirements set by water service providers. Specifically, these are outlined under Queensland’s water regulatory framework. In this case, the existing infrastructure had reached the end of its service life. Consequently, it no longer met trade wastewater compliance standards. Meanwhile, the centre’s food tenants collectively generated substantial fats, oils, and grease volumes. As a result, this placed ongoing pressure on an undersized system.

Adding to the complexity, the discharge line could not follow the original below-ground route. Existing services and structural constraints blocked the path. Therefore, Citi Industries needed to engineer an alternative route. Ultimately, this path had to satisfy hydraulic requirements while remaining practical for the site.

The main challenges included:

Regulatory deadline pressure: the existing system risked non-compliance with wastewater release requirements. Consequently, this created urgency around project delivery.
Active retail environment: installation occurred alongside daily foot traffic and tenant operations. As a result, robust pedestrian safety management was required.
Constrained discharge routing: the pump discharge line needed rerouting above ground. Specifically, it ran along the building’s external wall to the undercroft connection point.
Slab works: significant areas of existing concrete required cutting, removal, and replacement. Therefore, careful planning was essential.

What Was Delivered

Citi Industries managed the full scope of works from initial concrete scanning through to final slab reinstatement. The project involved commercial plumbing wastewater infrastructure and decommissioning of redundant assets. Furthermore, coordination with centre management ensured safe pedestrian access throughout.

Grease Trap Upgrade and Installation

Citi Industries installed a 2,000-litre Halgan below-ground grease trap as part of the grease trap upgrade. Essentially, this commercial unit intercepts fats, oils, and grease from wastewater. As a result, it prevents blockages and ensures trade wastewater compliance before discharge enters the sewer system.

The interceptor featured Class D lids rated for vehicular traffic loads. Notably, this specification was essential for the trap’s location. Delivery vehicles and maintenance equipment regularly access this area.

Sewer Pump Station Installation

A 1,200-litre REEFE dual sewer pump station replaced the original unit. Importantly, dual pump configurations provide redundancy. If one pump fails or requires servicing, the second maintains operation. As a result, wastewater flow from the premises continues without interruption.

The station included an electronic controller and high-level alarm. Specifically, the alarm triggers when wastewater levels exceed normal operating range. Consequently, maintenance teams receive alerts before overflow occurs. Additionally, a Class D vehicular-rated lid matched the access requirements of the adjacent grease trap.

The grease trap outlet connected directly to the sewer pump station inlet. From there, the discharge line ran above ground along the building’s side wall. Subsequently, it passed through the undercroft area and reconnected to the existing sewer.

System Ventilation

Each component required dedicated ventilation to manage gases and maintain consistent drainage flow. Accordingly, the grease trap, pump station, and trade waste drain line each received a 100mm vent pipe to atmosphere. Proper venting prevents airlock issues and controls odours. Additionally, it keeps wastewater moving through the network without obstruction.

Backflow Prevention Plumbing

Citi Industries installed a 20mm RPZD (Reduced Pressure Zone Device) backflow valve on the nearest hose tap. These backflow prevention devices stop contaminated water from flowing back into the potable supply. Notably, Queensland commercial plumbing regulations require a washdown tap with backflow protection. This must be within five metres of every new grease trap installation.

This tap allows staff to wash down access points during routine maintenance. In turn, this supports ongoing Urban Utilities compliance for the grease trap upgrade.

Decommissioning and Site Reinstatement

Before installing new infrastructure, the existing tanks required safe decommissioning. First, the team broke the base of both old units and applied lime treatment. Subsequently, the voids were backfilled. Meanwhile, relevant pipes were capped to prevent any future ingress or contamination.

Concrete scanning identified existing services before cutting began. Next, all affected slab areas were saw-cut, removed, and replaced with new concrete. The new surface matched the original specification. As a result, the reinstated areas support the same vehicle and pedestrian loads.

Throughout the works, barricading protected pedestrians from the active work zone. Safety barriers remained in place until concrete curing was complete. Finally, the area was cleared for public access.

Final Outcome

The shopping centre now operates with compliant trade wastewater infrastructure. Importantly, the system is sized for current tenant volumes and future growth. Centre management has confidence that the grease trap upgrade meets Urban Utilities requirements. As a result, the risk of enforcement action or tenant disruption is significantly reduced.

The completed grease trap upgrade delivered:

Full trade wastewater compliance achieved on schedule
Zero disruption to food tenant trading hours throughout the installation
Redundant sewer pump station providing operational continuity during maintenance
Reinstated surfaces matching original load ratings and finish

Ready to Upgrade Your Grease Trap System?

For shopping centre managers and commercial food operators, ageing grease traps present compliance risks and tenant disruption. Replacing an ageing grease trap before it fails avoids compliance notices, odour complaints, and unplanned disruption to tenants.

Citi Industries handles the full scope of hydraulic design, Urban Utilities approval, installation, and concrete reinstatement. Centre managers have one point of contact from start to sign-off. A correctly sized and installed system keeps trade waste approval current and reduces the frequency of pump-outs, lowering ongoing maintenance costs over time.

Call Citi Industries on 1300 136 036 to discuss your project.