Why Does My Grease Trap Smell?

Grease traps are essential components of commercial kitchens’ plumbing systems. They are designed to prevent fats, oils, and grease (FOG) from entering the sewer system, which can cause blockages and backups. However, grease traps can sometimes emit unpleasant odors. In this blog post, we will discuss the reasons why your grease trap might smell and what you can do to prevent it.

What is a Grease Trap?

A grease trap is a plumbing device that intercepts fats, oils, and grease (FOG) from wastewater. It is typically installed in commercial kitchens, restaurants, and other food service establishments. The grease trap works by slowing down the flow of wastewater, allowing the FOG to cool and solidify. The solidified FOG floats to the top of the grease trap, where it can be easily removed or pumped out.

Why Do Grease Traps Smell?

There are several reasons why your grease trap might smell. The most common reason is a buildup of FOG in the trap. When FOG is not removed regularly, food particles  can decompose and produce foul-smelling odors. Other reasons for grease trap odors include:

• Lack of maintenance: Grease traps need to be cleaned and maintained regularly to prevent odors.
• Improper installation: If the grease trap is not installed correctly, it may not function properly and can lead to odors. This happens alarmingly often.
• Damaged baffles: Baffles are the internal components of a grease trap that help to separate the FOG from the wastewater. If the baffles are damaged, the grease trap may not function properly.
• Food debris: Food debris can also contribute to grease trap odors. It is important to scrape plates and dispose of food scraps in the trash before washing dishes.
• Clogged drain lines: Clogged drain lines can also cause grease trap odors.

How Grease Traps Work

Grease traps work on the principle of density. FOG is less dense than water, so it floats to the top of the grease trap. The wastewater flows through the trap and exits through the outlet pipe (Outflow Tee.). The FOG is trapped in the grease trap and can be removed during cleaning. A grease trap pumper inserts a vacuum hose through a manhole cover (or grease trap access cover) and sucks the grease out near the manhole cover.

Maintenance of Grease Traps

Regular maintenance is essential to prevent grease trap odors and ensure proper functioning. The frequency of maintenance will depend on the size of the grease trap and the amount of FOG generated by the establishment. However, it is generally recommended that grease traps be cleaned at least once every three months. More specifically, most municipalities require adherence to the 25% rule which says that “the total depth of the floating grease layer plus the settle-able solids layer cannot exceed 25% of the total liquid depth of the interceptor.” Determination is made by taking a core sample with something like a Sludge Judge or Dipstick Pro, pictured here. 

Maintenance tasks include:

• Cleaning: The grease trap should be cleaned by a professional grease trap cleaning company. The cleaning process involves removing the accumulated FOG and other debris from the trap.
• Inspection: The grease trap should be inspected regularly for any signs of damage or malfunction.
• Repairs: Any damaged or malfunctioning components should be repaired or replaced promptly.

How Often Should Grease Traps Be Pumped Clean?

The frequency of grease trap pumping will depend on several factors, including the size of the trap, the amount of FOG generated, and the local regulations. However, as a general rule of thumb, most grease traps should be pumped clean every 1-3 months but the best schedule is to regularly apply and test with the 25% rule.

Things That Can Go Wrong with Grease Traps

Several things can go wrong with grease traps, leading to malfunctions and odors. These include:

• FOG buildup: Excessive FOG buildup can overload the grease trap and cause it to malfunction.
• Baffle damage: Damaged baffles can reduce the efficiency of the grease trap and lead to FOG escaping into the sewer system.
• Clogged inlet or outlet pipes: Clogged pipes can restrict the flow of wastewater and cause damage, plumbing issues and backups.
• Sewer line blockages: FOG that escapes the grease trap can solidify in the sewer lines and cause blockages. The cost of remediation and fines can be expensive.

Importance of a Professional Grease Trap Cleaning Partner

It is important to partner with a professional grease trap cleaning company to ensure proper maintenance and prevent odors. A professional company, such as Phoenix Pumping will have the experience and equipment to clean your grease trap or interceptor thoroughly and efficiently. They can also provide valuable advice on how to prevent future problems.

Preventing Grease Trap Odors

There are several things you can do to prevent grease trap odors:

• Train employees: Train your employees on the proper disposal of FOG and food scraps.
• Scrape plates: Scrape plates and dispose of food scraps in the trash before washing dishes.
• Dry wipe pots and pans: Dry wipe pots and pans before washing them to remove excess grease.
• Use drain strainers: Install drain strainers in all sinks to catch food scraps and other debris.
• Regular cleaning: Clean the grease trap regularly according to the manufacturer’s recommendations.
• Professional cleaning: Hire a professional grease trap cleaning company to clean the trap at least once every three months or more frequently if needed.

By following these tips, you can help to prevent grease trap odors and keep your kitchen smelling fresh and clean.

Additional Tips:

• Avoid using harsh chemicals: Harsh chemicals can damage the grease trap and the sewer system.
• Do not pour grease down the drain: Pouring grease down the drain is a major cause of grease trap problems.
• Dispose of FOG properly: Collect FOG in a separate container and dispose of it according to local regulations.
• Consider a grease interceptor: If your establishment generates a large amount of FOG, you may want to consider installing a grease interceptor. Grease interceptors are larger and more efficient than grease traps. Typically grease traps handle up to 50 gallons per minute. But interceptors are of two types and are sized differently. Gravity interceptors are not sized on flow but on capacity (volume) while hydromechanical interceptors are sized by volume of flow.

OCSD (Orange County Sanitation District) typically requires interceptors to be a minimum of 750 gallons and a maximum of 1500 gallons. In LA County the minimum capacity for a HGI interceptor is a 25 gallon per minute flow rate.

By following these tips and working with a professional grease trap cleaning company (Phoenix Pumping), you can ensure that your grease trap is functioning properly and prevent unpleasant odors.