New grease trap and interceptor problems can begin after a kitchen upgrade that seems harmless on the surface.

Replacing an old fryer with a newer model of the same size usually does not cause issues, especially if cooking volume stays consistent.

But when new equipment is added, rather than replaced, total grease-laden wastewater volume often increases. If interceptor cleaning frequency is not adjusted to account for that added load, grease traps that were previously compliant can begin to fail between services.

Why “One More Piece of Equipment” Can Change Everything

Grease interceptors are sized based on assumptions made at the time of installation. Those assumptions include menu mix, cooking methods, water volume, and peak discharge patterns. When new equipment is added, the interceptor does not adapt. It continues operating with the same capacity, retention time, and service schedule it always had.

Problems are most likely when:

• The original trap was sized close to the minimum allowed
• Added equipment increases both grease output and water volume
• Cooking methods shift toward higher-FOG production

Even modest changes can push a system past its functional limits.

Replacement Versus Addition Matters

Replacing a fryer with a newer or similar-capacity unit typically does not disrupt interceptor performance. The wastewater profile remains largely unchanged. Adding a second fryer, however, is different. The cumulative load increases, even if each individual appliance seems manageable.

Grease trap performance is about total system input, not individual appliances in isolation.

How New Equipment Disrupts Trap Performance

When equipment is added, three key dynamics often change at once.

Increased grease volume

More cooking surfaces mean more oils, fats, and food solids entering the drain system. Even small increases compound over time.

Higher water volume and heat

Many modern appliances discharge hotter water or create larger washdown volumes. Heat increases emulsification, allowing grease to pass through the trap instead of separating properly.

Shifted usage patterns

Menu changes often accompany equipment upgrades. A kitchen that moves from grilling to heavy deep-frying or adds fried-to-order items creates new prep and cleanup demands that increase discharge frequency and complexity.

Together, these changes reduce effective retention time and overwhelm service intervals that once worked reliably.

Equipment Types That Commonly Increase FOG Load

Certain equipment categories are known to stress grease interceptors more than others, especially when added to an existing layout.

Fryers and Double-Fryer Setups

Additional fryers increase oil usage, boil-out frequency and the volume of grease-laden wastewater entering the system, which can quickly exceed the capacity assumptions used to set cleaning intervals.

Tilt Skillets and Braising Pans

These units discharge large volumes of hot wastewater mixed with grease and food solids during cleaning, placing a heavy load on interceptors in a short period of time.

Combi Ovens

These units discharge high-temperature condensate and wash water during cooking and cleaning cycles. The heat and detergents keep grease emulsified, allowing more FOG to move through the system before separation occurs.

Dish Machines

Commercial dishwashers introduce short, high-volume surges of hot, detergent-heavy wastewater that can disrupt interceptor performance and push emulsified grease downstream.

Sauté or Wok Stations

These stations produce intermittent but concentrated bursts of FOG, which can overwhelm interceptors that were sized and serviced based on steadier, lower-output flow patterns.

Why Interceptors Don’t Always Fail Immediately

Many kitchens operate for weeks or months after adding equipment before problems surface. This happens because:

• Grease accumulation increases gradually
• Retention time erodes slowly
• Service intervals become insufficient without obvious warning

By the time backups, odors or inspection findings occur, the system has already been under stress for some time.

This delay often leads operators to miss the connection between the equipment change and the failure.

The Missing Step in Equipment Planning

Equipment planning usually focuses on electrical load, gas supply, ventilation and hood capacity. Downstream impacts, especially FOG load, are often overlooked. Installers and vendors rarely evaluate:

• Existing interceptor sizing relative to new discharge volumes
• Whether service frequency needs adjustment
• How heat and emulsification will affect separation

As a result, kitchens upgrade successfully on the front end while unknowingly creating problems below the slab.

What Facility Managers Should Do Before Installing New Equipment

Before approving new kitchen equipment, facility managers and operators should take a broader view of system impact. Best practices include:

• Reviewing interceptor size and original design assumptions
• Assessing how new equipment changes water volume, temperature and grease output
• Planning for adjusted service intervals if load increases
• Coordinating with grease management professionals early

Request an Assessment of Your Grease Interceptor Cleaning Frequency in Greater Metro-Atlanta

Southern Green Industries works with food service operators to evaluate interceptor performance after equipment additions, identify accumulative load issues and adjust service plans accordingly. Call us at (404) 419-6887 for a free quote and discuss your grease trap maintenance needs with local professionals.