Ultimate Guide for Cleaning & Maintaining a Grease Trap 

For businesses and industries, maintaining a grease trap is not just about adhering to regulations, but also about ensuring operations run efficiently.

The grease trap is vital for capturing and separating fats, oils, and grease (known as FOG) from wastewater. This prevents these substances from blocking drains and causing environmental issues.

In this comprehensive blog, we will answer what a grease trap is, how it works, the different types available, and the best practices for cleaning and maintenance.

What is a Grease Trap?

A grease trap, also known as a grease interceptor or grease recovery device, is a plumbing fixture designed to intercept fats, oils, and grease (FOG) from commercial and industrial wastewater.

As wastewater flows through the grease trap, the FOG cools and solidifies, separating from the water. The trapped grease accumulates in the web while the treated wastewater continues its journey to the sewer system or a wastewater treatment plant.

How Does a Grease Trap Work?

Grease traps work on the principle of gravity and buoyancy. When wastewater enters the trap, it cools down, causing fats, oils, and grease to rise to the surface due to their lower density than water.
The treated wastewater, which is relatively free of FOG, exits the grease trap through an outlet and continues its path to the sewer system. Meanwhile, solid food particles and other debris settle at the bottom of the trap, where they can be picked up and disposed of.

Different Types of Grease Traps

There are three main types of grease traps: 

Manual/Passive Hydromechanical Grease Interceptors (HGI)

Manual grease trap

Manual or “passive hydrochemical HGI” grease traps have been commonplace in restaurants and commercial kitchens for over a century. Typically made of stainless steel or plastic, these traps need to be cleaned regularly.
HGIs utilize a combination of gravity and mechanical features for grease separation. They are equipped with a series of baffles and separators that enhance the FOG removal process, making them ideal for large-scale industrial operations.

Automatic Grease Recovery Units (AGRU)

automatic grease trap

Automatic grease traps are known as “automatic grease removal units” or “AGRUs” among grease-trap insiders. This system is often located underneath a 3-compartment sink or floor of a kitchen. AGRU systems use mechanical means to separate grease from wastewater automatically. They are equipped with skimmers or augers that continuously remove and store the trapped grease for later disposal or recycling.
AGRUs are more suitable for high-volume food establishments and offer convenience and efficiency in grease removal. The container can be emptied daily and made ready for collection by a hazardous waste disposal service regularly. A manual grease trap, on the other hand, must be emptied and cleaned by a specialist every two to four weeks.

Gravity Grease Traps

gravity grease trap

Gravity grease traps, also called “gravity grease interceptors” or “GGI’s,” are the most common type and are typically installed underground. These traps rely on the force of gravity to separate FOG from wastewater.
Gravity grease interceptors are often made out of concrete but can be made out of steel, fiberglass, or plastic. They come in various sizes to accommodate different flow rates and are ideal for restaurants, cafeterias, and other food service establishments.
Government regulations require them to be pumped out whenever the percentage of grease reaches 25%. Because they are placed in small locations, GGIs are rarely practicable for kitchens that produce modest amounts of fats and oils.

What Happens When Grease Traps Fail?

Maintenance of grease traps, whether manual or automatic, is critical. What might happen if a grease trap is not properly maintained? FOG can harden and begin to seep out. Furthermore, if the pipes downstream from the grease trap become clogged with FOG sludge, the grease trap may become overwhelmed. This will cause your trap to fill with effluent, forcing local sanitary officials to close your restaurant or establishment.
This would cause a huge headache for you and your business. If you maintain a grease trap from the start, you won’t have to deal with issues later on. That is why it is important to know how to properly clean and maintain your grease trap to save you time and money, rather than wasting resources on extra hazardous waste cleanup.

How to Clean and Maintain a Grease Trap

Here are essential grease trap cleaning and maintenance guidelines to follow:

  • Regular Cleaning Schedule: Develop a routine cleaning schedule based on your establishment’s grease production and the size of the grease trap. A professional grease trap cleaning service should pump and remove the trapped grease at least every 30 to 90 days.
  • Scrape Grease Interceptor Walls: During cleaning, scrape the walls and baffles of the grease trap to remove any adhered grease buildup thoroughly. This will prevent further build-up or potential blockages.
  • Dispose of Grease Properly: Ensure that the collected grease is disposed of correctly in compliance with local regulations. Consider recycling options, such as AllSource Environmental Hazardous and Non-Hazardous Waste pickup.
  • Monitor and Inspect: Regularly inspect the grease trap for signs of damage or potential issues. Address any problems promptly to prevent costly repairs and ensure optimal performance. This is also beneficial to the safety of you, your business, your staff, and your customers.
  • Educate Staff: Train your staff on proper waste disposal practices to prevent debris and food particles from entering the grease trap. This is a step we highly recommend putting extra time and care into, especially if you personally aren’t going to be cleaning and maintaining the grease traps regularly.
  • Stay Clear of Chemicals: It is generally advised to stay away from adding chemicals to degrease a trap. Adding bleach, emulsifiers, enzymes, or any other chemicals or degreaser cleaner can kill the natural bacteria that is inside the grease traps– and important to the proper functioning of the grease trap. Also, many of these substances don’t break down FOG, only separate it from the wastewater. This can lead to other issues.

Additional Tips for Proper Grease Trap Maintenance

If you don’t take good care of your grease traps or if you use strong degreasers, you might end up with bad smells, blockages, and spills. These kitchen mishaps can seriously disrupt your business, potentially leading to a temporary closure and damaging your reputation. Here are some additional tips:

  • Install a strainer or basket in sinks and drains to capture large food particles and solid debris.
  • Avoid pouring hot water or chemicals down the drain, as they can dissolve grease, causing it to bypass the grease trap.
  • Keep detailed records of maintenance and cleaning activities, including dates and service provider information, for regulatory compliance.
  • If you fear FOG has clogged the plumbing downstream from your grease trap, line-jetting or sewage line jetting is an excellent approach to clear the blockage. If you fear FOG has clogged the plumbing downstream from your restaurant grease trap, line-jetting or sewage line jetting is an excellent approach to clear the blockage.

At AllSource Environmental, we view industrial waste not as a mere issue to manage, but as a chance to lower costs, boost sustainability, and maintain a competitive advantage. Our expertise extends to both hazardous and non-hazardous cleaning services. Allow us to assist you in turning challenges into opportunities. Reach out to us today for a free consultation.