Proper wastewater management is paramount in the world of commercial sewer systems, where excessive fat, oil, and grease (FOG) pose a significant threat.
The accumulation of these substances can cause clogs and blockages, resulting in environmental hazards and costly repairs. To combat this problem, the installation and correct sizing of grease interceptors play a vital role.
Here I’ll look at the significance of grease interceptors, explore how different municipalities or companies size them, and provide valuable tips on involving engineers in the replacement process.
The role of grease interceptors
Grease interceptors, also known as grease traps or grease chambers, act as a barrier against FOG by intercepting and storing it before it enters the sewer system. These devices function as physical traps, allowing wastewater to flow through while capturing and retaining FOG. By separating FOG from wastewater, grease interceptors play a crucial role in preventing blockages and minimizing the adverse effects on sewer systems.
Sizing grease interceptors
The correct sizing of grease interceptors is vital to address the demands of each commercial establishment effectively. Determining the appropriate size involves considering various factors such as the type of facility, estimated wastewater flow, and local regulatory requirements.
Although different municipalities or companies may employ distinct sizing methods, two commonly used approaches are the hydraulic load method and the plumbing fixture method.
Hydraulic load method
The hydraulic load method focuses on estimating the anticipated grease load based on the facility's daily water usage. This method employs a formula to calculate the FOG load: Flow (in gallons per day) x FOG concentration (in parts per million) x conversion factor. The conversion factor, usually provided by local guidelines, ensures accuracy in calculating the grease load.
For instance, let's consider a restaurant with an estimated daily water usage of 10,000 gallons and a FOG concentration of 150 parts per million. If the conversion factor is 0.0025, the FOG load can be determined as follows: FOG load = 10,000 x 150 x 0.0025 = 3,750 pounds per day.
Plumbing fixture method
The plumbing fixture method estimates the grease load by considering the number and type of fixtures within the establishment. Each fixture category, such as sinks, dishwashers, or floor drains, is assigned a specific grease load value. By totaling the respective loads, the required size of the grease interceptor can be determined.
For example, in a commercial kitchen with three sinks, two dishwashers, and two floor drains, the assigned grease loads may be as follows: sinks (100 gallons per day), dishwashers (200 gallons per day each), and floor drains (50 gallons per day each). The total grease load would be 600 gallons per day, which can be used to size the grease interceptor accurately.
Engineer involvement in grease interceptor sizing
To ensure the accurate sizing and replacement of grease interceptors, the involvement of engineers is crucial. Their expertise will help maintain compliance with local regulations and prevent potential issues. Here are some tips on involving engineers effectively in the sizing process.
Seek professional consultation: When faced with the need to replace a grease interceptor, it is essential to reach out to experienced engineers who specialize in commercial sewer systems. Their technical knowledge and expertise allow them to assess your current setup accurately and determine the appropriate replacement size.
Collaborate with local municipalities: Engaging with local municipalities plays a vital role in understanding their specific sizing requirements. Municipal regulations may differ, and an engineer familiar with those nuances can help navigate the compliance process smoothly.
Conduct a site evaluation: An engineer will conduct a comprehensive site evaluation to assess various factors, such as wastewater flow rates, fixture types, and existing plumbing configurations. They will also consider any physical limitations or space constraints that could impact the sizing and replacement process.
Consider future growth and expansion: Engineers take into account potential future growth and expansion plans when sizing the new grease interceptor. Ensuring that the installation can accommodate increased wastewater demands will save you from undertaking costly modifications in the future.
Stay informed and involved: Through ongoing communication, regularly consult engineers and actively engage with their recommendations during the sizing and installation process. Discuss any modifications or considerations required for the new grease interceptor to cater to your establishment's specific needs effectively.
About the Author
Anthony Pacilla is a registered master plumber for McVehil Plumbing in Washington, Pennsylvania. He has over two decades of experience in the plumbing and HVAC trades and has a bachelor’s in business and economics from Thiel College.
