What is the difference between a septic tank and a grease interceptor?

• A. A septic tank handles domestic wastewater; a grease interceptor traps fats/oils before entering the septic system or drainfield.
• B. A grease interceptor handles domestic wastewater.
• C. They are identical.
• D. A septic tank replaces a grease interceptor.

Answer: (A)

A septic tank and a grease interceptor serve different jobs in wastewater management. A septic tank is the on-site treatment unit that receives domestic wastewater from a home—toilets, sinks, showers, and laundry. It separates solids from liquids and begins anaerobic digestion, with scum on top and clarified liquid exiting to the drainfield.

A grease interceptor, on the other hand, is a pretreatment device used to remove fats, oils, and grease from kitchen wastewater before it goes into the septic system or the sewer. It’s designed to prevent FOG from reaching the drainfield or sewer lines, using baffles and settling to trap grease so it can be cleaned out regularly.

So the difference lies in purpose and placement: septic tanks handle general household wastewater and begin treatment on-site, while grease interceptors specifically trap fats/oils before the wastewater enters the septic system or drainfield.