Grease Trap Additives, Enzymes and Bacteria: What They Actually Do

The claim and the chemistry

Additives promise to “digest” or “dissolve” grease so the trap stays empty. Some are enzymes, some are bacterial cultures, some are solvents. What all of them do in practice is break the grease cap into smaller droplets or emulsify it into the water column. The grease does not disappear. It leaves — through the outlet, into your lateral, and into the city sewer. The trap looks cleaner because the grease is now the city’s problem.

Why that is the wrong trade in Richmond

Richmond’s standard is 100 ppm of fat, oil and grease in what you discharge (Sec. 28-907). A trap is a device for keeping grease out of that number. An additive is a device for putting it back in. If the city samples your discharge, an emulsified trap is the one that fails, and the code lets the city bill you for treatment costs and, for violations, discontinue service. Downstream, emulsified grease re-congeals in cooler pipes — which is how a kitchen that “never has trap problems” ends up named in a sewer blockage.

What works instead

• Scrape plates into the trash before they hit the sink. Solids are half of what fills a trap.
• Dry-wipe fryer baskets and pans before washing.
• Keep the dish machine off the trap line if your plumbing allows — or size up.
• Pump on the interval the calculator gives you, with full evacuation every time.

If a vendor sells you an additive

Ask them to put in writing that it will not increase the fat, oil and grease in your discharge. They will not, because it does. Then ask for the gallons-removed figure on your last receipt. If there is not one, that is the problem the additive was hiding.