Automatic Grease Removal Units (AGRUs): Pros, Cons & Melbourne Applications

What Are Automatic Grease Removal Units?

Automatic grease removal units — commonly known as AGRUs — are the most technologically advanced grease management systems available to Melbourne commercial kitchens. Unlike traditional passive grease traps that simply hold wastewater and rely on gravity separation, AGRUs actively skim, heat and remove grease on a programmed cycle, typically once or twice per day. The result is consistently high separation efficiency, reduced odour and significantly less manual maintenance.

AGRUs are recognised under AS 4674 and are approved by Melbourne Water as an alternative to conventional grease traps for many commercial applications. For a comparison of all grease trap types, see our complete guide to grease trap types.

How AGRUs Work

An AGRU is typically installed inside the kitchen, connected to specific drainage fixtures. Here is the basic operating cycle:

• Collection phase: Wastewater flows into the unit and FOG separates from water by gravity, rising to the surface
• Heating cycle: A built-in heating element warms the collected grease layer, making it liquid and easier to remove
• Skimming cycle: A motorised skimming mechanism sweeps across the surface, collecting liquefied grease and directing it into an external collection container
• Drainage: Treated water exits the unit to the sewer. The grease container is emptied periodically — typically weekly or fortnightly

The entire cycle is automated and programmable, usually set to run during off-peak hours (overnight or between services). This means the unit is always operating at near-optimal efficiency when your kitchen opens each day.

Advantages of AGRUs

Consistently High Grease Removal Efficiency

Because grease is removed automatically on a regular cycle, an AGRU never reaches the overloaded state that passive traps experience between pump-outs. Studies show AGRUs maintain 90% or higher grease removal efficiency throughout their operating cycle, compared to passive traps which can drop below 50% as they fill.

Reduced Odour

One of the biggest complaints about passive grease traps — particularly above-ground units — is smell. Because AGRUs remove grease daily, there is far less decomposing organic material in the unit at any time. This is a significant benefit for Melbourne restaurants and cafes where the trap is located inside or near the dining area.

Lower Ongoing Maintenance

AGRUs eliminate the need for regular vacuum truck pump-outs. Kitchen staff simply replace or empty the grease collection container as needed. This can substantially reduce annual maintenance costs for high-volume kitchens.

Smaller Footprint

AGRUs are typically more compact than equivalent-capacity passive traps. This is valuable in Melbourne’s inner-city kitchens where space is at a premium.

Better Compliance Record

Because AGRUs maintain consistent performance, businesses using them tend to have fewer trade waste compliance issues with Melbourne Water. The units also include monitoring capabilities — some models log operating data that can be presented to inspectors as evidence of proper maintenance.

Disadvantages of AGRUs

Higher Upfront Cost

AGRUs are significantly more expensive to purchase and install than passive grease traps. Depending on capacity and brand, expect to pay $5,000 to $20,000 or more for the unit alone, plus installation costs. Passive traps of equivalent capacity may cost a third to half as much.

Mechanical Complexity

With heating elements, motors, timers and electronic controls, AGRUs have more components that can fail. Regular servicing by qualified technicians is essential. If the unit malfunctions and is not repaired promptly, grease removal stops and you are effectively operating without a trap.

Power Requirements

AGRUs require an electrical connection, adding to operating costs and installation complexity. This is not a significant expense, but it is an additional consideration compared to passive traps that require no power.

Not Suitable for All Premises

AGRUs work best with consistent, moderate FOG loads. Kitchens with extremely high or highly variable grease output — such as large-scale deep-frying operations — may still require a large in-ground trap for primary treatment, with an AGRU as a secondary polishing unit.

Cost Comparison: AGRU vs Passive Grease Trap

Here is a realistic cost comparison for a medium-sized Melbourne restaurant over five years:

• Passive in-ground trap (2,000L): $6,000 installation + $3,000/year maintenance = $21,000 total over 5 years
• AGRU (equivalent capacity): $12,000 installation + $1,200/year maintenance + $500/year power and parts = $20,500 total over 5 years

The numbers converge over time, and for high-FOG kitchens the AGRU can actually be cheaper over its lifetime due to reduced pump-out costs. The break-even point is typically 3 to 5 years.

Ideal Melbourne Applications for AGRUs

• Inner-city restaurants and cafes where space is limited and odour control is critical
• Hotels and convention centres with high-volume kitchens and strict hygiene standards
• Hospitals and aged care facilities where consistent compliance is non-negotiable
• Multi-storey buildings where in-ground installation is not feasible
• New builds where the higher upfront cost can be factored into the construction budget

AGRU Brands Available in Melbourne

Several reputable manufacturers supply AGRUs to the Australian market, including Grease Guardian, Goslyn, Thermaco Big Dipper and FM Environmental. All units sold in Melbourne should comply with AS 4674 and be approved by the relevant water authority. We can advise on the best unit for your specific application.

Is an AGRU Right for Your Business?

AGRUs are an excellent choice for many Melbourne food businesses, but they are not the right fit for everyone. The decision depends on your FOG volume, available space, budget and maintenance preferences. Our team can assess your kitchen, compare options and recommend the most cost-effective grease management solution. Learn more about our AGRU services or contact us for a free consultation.