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Grease trap for greywater in Lima, Peru

A grease trap (also known as a grease interceptor, grease recovery device, grease capsule, or grease converter) is a plumbing device (a type of trap) designed to intercept most greases and solids before they enter a wastewater disposal system. Common wastewater contains small amounts of oils which enter into septic tanks and treatment facilities to form a floating scum layer. This scum layer is very slowly digested and broken down by microorganisms in the anaerobic digestion process. Large amounts of oil from food preparation in restaurants can overwhelm a septic tank or treatment facility, causing the release of untreated sewage into the environment. High-viscosity fats and cooking grease such as lard solidify when cooled, and can combine with other disposed solids to block drain pipes.

Grease traps have been in use since the Victorian era; in the late 1800s, Nathaniel Whiting was granted the first patent. The quantity of fats, oils, greases, and solids (FOGS) that enter sewers is decreased by the traps. They consist of boxes within the drain run that flows between the sinks in a kitchen and the sewer system. They have only kitchen wastewater flowing through them and do not serve any other drainage system, such as toilets. They can be made from various materials, such as stainless steel, plastics, concrete and cast iron. They range from 35-liter capacity to 45,000 litres and greater. They can be located above ground, below ground, inside the kitchen, or outside the building.

Types

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Manhole covers of a grease trap outside a restaurant.

There are three primary types of devices. The most common are those specified by American Society Of Mechanical Engineers (ASME), utilizing baffles, or a proprietary inlet diffuser.

Grease trap sizing is based on the size of the 2- or 3-compartment sink, dishwasher, pot sinks, and mop sinks. Many manufacturers and vendors offer online sizing tools to make these calculations easy. The cumulative flow rates of these devices, as well as overall grease retention capacity (in pounds or kilograms) are considered. Currently, ASME Standard (ASME A112.14.3) is being adopted by both of the national model plumbing codes (International Plumbing Code and Uniform Plumbing Code) that cover most of the US. This standard requires that grease interceptors remove a minimum of 90% of incoming FOGs. It also requires that grease interceptors are third-party tested and certified to 90 days compliance with the standard pumping. This third-party testing must be conducted by a recognized and approved testing laboratory.[1]

Passive grease traps are generally smaller, point-of-use units used under three-compartment sinks or adjacent to dishwashers in kitchens.

Large in-ground tanks, usually 500–2,000 US gallons (2,000–8,000 L), are also passive grease interceptors. These units, made of concrete, fiberglass, or steel, have greater grease and solid storage capacities for high-flow applications such as a restaurant or hospital store. They are commonly called gravity interceptors. Interceptors require a retention time of 30 minutes to allow the fats, oils, grease, and food solids to settle in the tank. As more wastewater enters the tank, the grease-free water is pushed out of the tank. The rotting brown grease inside a grease trap or grease interceptor must be pumped out on a scheduled basis. The brown grease is not recycled and goes to landfills. On average 300 to 400 pounds (140 to 180 kg) of brown grease goes to landfill annually from each restaurant.[2]

Passive grease traps and passive grease interceptors must be emptied and cleaned when 25% full. As the passive devices fill with fats, oils, and grease, they become less productive for grease recovery. A full grease trap no longer prevents FOG from entering the sanitary sewer system. The emptied contents or "brown grease" is considered hazardous waste in many jurisdictions.[citation needed]

A third system type, hydromechanical grease interceptors (HGIs), has become more popular in recent years as restaurants open in more nontraditional sites. Often, these sites don't have space for a large concrete grease interceptor. HGIs take up less space and hold more grease as a percent of their liquid capacity — often between 70 and 85% of their liquid capacity or even higher as in the case of some "Trapzilla" models. These interceptors are 3rd-party certified to meet efficiency standards. Most are made out of durable plastic or fiberglass, lasting much longer than concrete gravity grease interceptors. They are usually lightweight and easy to install without heavy equipment. Most manufacturers test beyond the minimum standard to demonstrate the full capacity of the unit.[2][3]

Finally, automatic grease removal devices or recovery units offer an alternative to hydromechanical grease interceptors in kitchens. While their tanks passively intercept grease, they are equipped with an automatic, motorized mechanism that removes grease from the tank and collects it in a separate container. These interceptors must meet the same efficiency standards as a passive HGI, but must also meet an additional standard that proves they are capable of skimming the grease effectively.[citation needed]

They are often designed to be installed unobtrusively in a commercial kitchen, in a corner, or under a sink. The upfront cost of these units can be higher, but kitchen staff can handle the minimal maintenance required, avoiding pumping fees. The compact design of these units allows them to fit in tight spaces, and simplifies installation.[citation needed]

Uses

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In-ground grease trap outside of a shop

Restaurant and food service kitchens produce waste grease which is present in the drain lines from various sinks, dishwashers and cooking equipment such as combi ovens and commercial woks. Rotisserie ovens have also become big sources of waste grease.[4] If not removed, the grease can clump and cause blockage and back-up in the sewer.

In the US, sewers back up annually an estimated 400,000 times, and municipal sewer overflows on 40,000 occasions.[5][full citation needed] [6] The U.S. Environmental Protection Agency has determined that sewer pipe blockages are the leading cause of sewer overflows, and grease is the primary cause of sewer blockages in the United States.[7] Even if accumulated FOG does not escalate into blockages and sanitary sewer overflows, it can disrupt wastewater utility operations and increase operations and maintenance requirements.[8]

For these reasons, depending on the country, nearly all municipalities require commercial kitchen operations to use some type of interceptor device to collect grease before it enters sewers.[9] Where FOG is a concern in the local wastewater system, communities have established inspection programs to ensure that these grease traps and/or interceptors are being routinely maintained.[10]

It is estimated 50% of all sewer overflows are caused by grease blockages, with over 10 billion US gallons (38,000,000 m3) of raw sewage spills annually.[citation needed]

Method of operation

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When the outflow from the kitchen sink enters the grease trap, the solid food particles sink to the bottom, while lighter grease and oil float to the top. The relatively grease-free water is then fed into the normal septic system.The food solids at the bottom and floating oil and grease must be periodically removed in a manner similar to septic tank pumping.[11] A traditional grease trap is not a food disposal unit. Unfinished food must be scraped into the garbage or food recycling bin. Gravy, sauces and food solids must be scraped off dishes before entering the sink or dishwasher.

To maintain some degree of efficiency, there has been a trend to specify larger traps. Unfortunately, providing a large tank for the effluent to stand also means that food waste has time to settle to the bottom of the tank, reducing available volume and adding to clean-out problems. Also, rotting food contained within an interceptor breaks down, producing toxic waste (such as sulfur gases); hydrogen sulfide combines with the water present to create sulfuric acid. This attacks mild steel and concrete materials, resulting in "rot out", On the other hand, polyethylene has acid-resisting properties. A larger interceptor is not a better interceptor. In most cases, multiple interceptors in series will separate grease much better.[citation needed]

Because it has been in the trap for some time, grease thus collected will be contaminated and is unsuitable for further use. This type of grease is called brown grease.[citation needed]

Brown grease

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Waste from passive grease traps and gravity interceptors is called brown grease. Brown grease is rotted food solids in combination with fats, oils, and grease (FOG). Brown grease is pumped from the traps and interceptors by grease pumping trucks. Unlike the collected yellow grease, the majority of brown grease goes to landfill sites. New facilities and new technology are beginning to allow brown grease to be recycled.[12]

References

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Grease trap

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A grease trap, also known as a grease interceptor in larger installations, is a plumbing device designed to capture and retain fats, oils, and grease (FOG) from wastewater before it enters the sanitary sewer system, primarily in commercial food service establishments such as restaurants and cafeterias. Grease traps have been in use since the Victorian era, with the first patent for a modern design granted to American inventor Nathaniel Whiting in 1884. These devices function by allowing wastewater to flow through a baffled or compartmentalized chamber where lighter FOG materials float to the surface and solids settle, separating them from the cleaner effluent that proceeds to the sewer. The primary purpose of grease traps is to prevent FOG accumulation in sewer lines, which can lead to blockages, sanitary sewer overflows (SSOs), costly repairs, and environmental from untreated spills. By intercepting FOG—organic compounds derived from animal and vegetable sources like cooking oils and meat fats—these devices reduce the risk of sewer backups that cause foul odors, , and health hazards in communities. Under the U.S. Environmental Protection Agency's National Pretreatment Program, including the prohibition on solids or viscous substances causing obstruction in 40 CFR 403.5(b)(3), local regulations often mandate their installation and maintenance in facilities generating significant FOG, with common effluent limits of 100 mg/L or lower for oil and grease to ensure compliance. Grease traps come in various types to suit different scales of operation, including small hydromechanical grease interceptors for indoor use and larger gravity grease interceptors installed outdoors. Proper sizing and regular maintenance are essential for effective operation.

Introduction

Definition and Purpose

A is a device designed to intercept and separate fats, oils, and grease (FOG), along with solids, from streams generated in service establishments before the effluent reaches systems. These devices primarily employ gravity-based separation, where FOG rises to the surface due to its lower compared to , enabling retention while clearer flows onward. Some grease traps incorporate mechanical elements, such as baffles or flow controls, to enhance this interception process. The core purpose of a grease trap is to mitigate the risks posed by FOG accumulation in drainage infrastructure, including pipe blockages, sewer line clogs, backups, and overflows that can result in environmental and hazards. By capturing FOG at the source, these devices safeguard municipal plants from overload and inefficiency caused by greasy buildup, which could otherwise disrupt treatment processes and increase operational costs. This preventive role is essential in commercial settings like restaurants, where high volumes of FOG are produced during preparation and . In common usage, the term "grease trap" often refers to smaller, indoor units—such as under-sink or floor-mounted models with capacities typically ranging from 25 to 75 gallons—installed within to handle moderate flows. In contrast, "grease interceptor" denotes larger, typically outdoor systems with capacities of 250 gallons or more, suited for higher-volume operations and positioned outside the facility to manage substantial loads before discharge to sewers. This distinction highlights their scalable application in protecting sewer systems across various facility sizes.

History

The grease trap was invented in the late as a solution to separate fats, oils, and grease from in systems. In 1884, Nathaniel Whiting of , , received the first U.S. for a grease trap (U.S. Patent No. 306,981), describing a simple gravity-based device consisting of a buried box positioned under sinks to allow grease to float and solidify for removal while permitting cleaner water to drain away. This innovation addressed early urban challenges by preventing grease buildup in sewers, marking the foundational design that relied on the principle of difference between grease and water. Early developments in the centered on basic buried box configurations installed directly beneath sinks or in drain lines, with designs emphasizing passive gravity separation and minimal mechanical intervention. These early grease traps were often constructed from cast iron or coated steel and installed in-floor as passive or hydromechanical interceptors, common before the advent of modern plastic or composite materials, with typical ratings of 20–100 lbs grease retention capacity or 10–50 GPM flow rates. These systems saw little evolution through the early , as the core concept remained focused on static containment. By the 1930s, improvements emerged in gravity-based traps, incorporating increased water volume to slow flow rates and enhance separation efficiency, allowing more time for grease to rise and coalesce before effluent discharge. Advancements in the mid-20th century introduced hydromechanical grease traps, which integrated flow controls, baffles, and compact designs to improve in high-volume commercial kitchens, such as restaurants, while maintaining the unchanged gravity separation principle established by Whiting's patent. These traps, often required in building codes post-World War II, addressed growing demands from urban expansion and food service industries by reducing space needs compared to larger interceptors. Entering the , environmental regulations, including the U.S. amendments and similar international standards, spurred the development of automatic grease removal devices and larger-scale interceptors to minimize fats, oils, and grease discharge into waterways, though the foundational gravity mechanism from the 1884 patent continues to underpin all modern iterations.

Types

Hydromechanical Grease Traps

Hydromechanical grease traps, also known as hydromechanical grease interceptors, are passive devices designed for indoor use to separate fats, oils, and grease () from in commercial kitchens through -based separation enhanced by hydraulic flow control. These units are typically compact, with capacities ranging from 5 to 50 gallons, making them suitable for installation under sinks or inline with plumbing fixtures. They operate without mechanical or powered components, relying instead on differences in specific , , and controlled flow to promote FOG flotation while retaining solids. Key design features include internal baffles that direct and slow the incoming , allowing FOG to rise to the surface, and flow restrictors—often vented devices—that limit the rate of discharge to enhance retention time. and outlet are standard, with the tee positioned to direct flow downward, trapping heavier solids at the bottom of the unit to prevent re-entrainment. Older models were often constructed from cast iron or coated steel, particularly for in-floor installations common before the widespread use of modern plastic and composite materials, while contemporary units are made from materials like , , or . These traps form a single compartment optimized for point-of-use applications near grease-producing fixtures. Certified units comply with standards such as PDI-G101, which tests for flow rates of 2 to 100 gallons per minute (GPM) and grease retention capacities from 4 to 200 pounds; historical variants of these hydromechanical traps typically featured ratings of 20–100 lbs grease capacity or 10–50 GPM flow. In operation, from hot kitchen sources enters the trap, where the drops sufficiently—typically below 140°F—for to solidify and float upward due to its lower compared to . The slowed flow, facilitated by restrictors and baffles, provides the necessary retention time (often 2 to 5 minutes) for separation, with cleaner exiting via the outlet tee positioned below the FOG layer. This process continuously intercepts FOG without interruption to drainage, though performance depends on proper conditions and avoidance of that could emulsify the grease. These traps offer advantages in cost-effectiveness and ease of installation in confined spaces, ideal for low- to medium-volume fixtures such as single pot sinks or prep stations. Their small footprint reduces material and labor costs compared to larger systems, and they effectively prevent from entering building drains when used appropriately. However, limitations include reduced efficiency in high-flow environments exceeding their rated GPM, where insufficient retention time allows bypass. They also necessitate frequent manual cleaning to remove accumulated and solids, as overload can diminish separation effectiveness. Examples of compliant passive units include those rated under PDI-G101 for 20-50 GPM flows in single-compartment designs.

Gravity Grease Interceptors

Gravity grease interceptors are large-scale, passive devices designed for high-volume fats, oils, and grease () removal in commercial food service facilities, typically installed outdoors or below floors to handle wastewater from an entire building. These systems utilize compartmentalized tanks, often constructed from , fiber-reinforced polyester (FRP), (HDPE), or materials, with capacities ranging from 500 to 15,000 gallons or more to accommodate substantial drainage fixture units (DFUs). The design incorporates multiple chambers—commonly two or three—divided by baffles that create distinct , separation, and outlet zones, ensuring even flow distribution and preventing short-circuiting of . Baffles, including influent distribution baffles with larger slots, reduce inlet velocity to below 0.6 inches per second, promoting a quiescent environment for effective separation. These interceptors must comply with standards such as IAPMO/ANSI Z1001 for prefabricated units, which specifies testing for hydraulic flow ratings and FOG retention efficiency. In operation, enters the inlet chamber at a controlled low , allowing to drive the without any moving parts. The extended retention time—typically a minimum of 30 minutes at peak flow—enables lighter FOG particles to rise and form a floating layer in the separation zone, while heavier solids settle to the bottom, creating a clear zone in the middle for discharge through the outlet. This passive mechanism relies on and principles, with the multi-chamber configuration enhancing separation by minimizing turbulence and ensuring progressive clarification across zones. For instance, a unit sized for 29 DFUs might hold 1,000 gallons, supporting flow rates up to 100 gallons per minute (GPM) or higher in larger installations serving multiple fixtures. These interceptors offer significant advantages for high-flow applications, including robust storage capacity for accumulated FOG and solids, which supports their use in processing from entire facilities like restaurants. Their durable construction, particularly models, provides long-term structural integrity and suitability for buried or semi-buried outdoor placement, reducing exposure risks in food preparation areas. However, they require substantial space for installation and incur high initial costs due to their size and materials, often exceeding those of smaller indoor alternatives. Additionally, improper sealing or venting can lead to odor issues from formation, particularly if oversized or under-maintained.

Automatic Grease Removal Devices

Automatic Grease Removal Devices (AGRDs), also known as Automatic Grease Removal Units (AGRUs), are powered hydromechanical systems designed to actively separate and extract fats, oils, and grease () from in commercial kitchens. These compact units, typically ranging from 20 to 100 gallons in capacity, feature integrated sensors, pumps, and skimming mechanisms to automate removal into a dedicated storage tank, minimizing manual handling. Many models incorporate heating elements to liquefy and maintain separation efficiency, constructed from durable materials like 304 for corrosion resistance and ease of installation in space-constrained environments such as under sinks or in basements. In operation, AGRDs rely on to power removal cycles triggered by level sensors or timers, ensuring continuous monitoring and extraction of floating without interrupting flow. The process often includes a multi-stage separation involving initial solids retention, followed by FOG skimming via rotating drums or augers at rates up to 5 liters per hour, and a self-cleaning spray system to prevent buildup. Some units integrate coalescing media to enhance capture of finer FOG particles, while examples like the Grease Guardian GGX series comply with standards such as PDI G101 for separation and ASME A112.14.4 for automatic removal functionality, including UL-listed electrical components for safety. The extracted FOG is collected in external containers suitable for into biofuels, producing nearly water-free output. These devices offer significant advantages in busy commercial settings by reducing manual intervention to periodic emptying of storage tanks, potentially cutting pump-out frequency from monthly to twice yearly. They achieve high removal efficiency, often exceeding 90% for free-floating substances, making them ideal for moderate-flow kitchens with limited space where passive systems may underperform. However, AGRDs consume more due to electrical components like 25-1000W heaters and motors, and require regular maintenance of sensors and pumps to avoid failures, rendering them less suitable for very high-volume operations where larger gravity systems are preferred.

Design and Operation

Principles of Operation

Grease traps operate primarily on the principle of separation, exploiting the difference between fats, oils, and grease () and . FOG typically has a specific of approximately 0.89 to 0.90, compared to 's specific of 1.0, causing it to float to the surface when wastewater flow is slowed. This buoyancy-driven process is enhanced by retention time within the trap, which allows hot kitchen —often exceeding 140°F (60°C)—to cool sufficiently for FOG to congeal and solidify, improving separation efficiency. Flow dynamics in grease traps are designed to minimize and promote conditions for effective separation. Incoming enters through inlet structures that reduce velocity, fostering and allowing FOG globules to coalesce and rise without being carried away. Design and performance are often governed by standards such as PDI G101 for hydromechanical units and ASME A112.14.4 for gravity units. Typical retention times are approximately 2 minutes in hydromechanical grease traps, providing adequate dwell time for separation while handling peak flows without overflow. Heavier food particles and solids in the wastewater settle to the bottom due to their greater density, forming a sludge layer that accumulates separately from the floating FOG. This passive stratification occurs without the use of chemical additives in standard operations, relying solely on physical and hydraulic forces. Grease traps can efficiently remove larger FOG particles (≥150 microns) via gravity separation, though performance depends on factors such as temperature differentials and wastewater velocity, which influence coalescence and settling rates. Smaller emulsified FOG particles may pass through, highlighting the importance of proper design for targeted removal.

Key Components

Grease traps typically feature inlet and outlet pipes designed to manage flow effectively. These pipes are fitted with tees or vents that direct the incoming flow downward into the trap, minimizing and preventing short-circuiting where grease could the . To ensure optimal performance, flow control valves or restricting devices are often incorporated to limit the flow rate to the trap's rated capacity, thereby allowing sufficient retention time for grease separation. Internal baffles and compartments form the core structural elements that facilitate grease interception in most grease traps. These dividers, typically numbering one to three per unit, create sequential zones within the trap where wastewater slows and grease rises to the surface for retention. Baffles are commonly constructed from corrosion-resistant materials such as or (HDPE) to withstand the acidic and greasy environment over time. Access covers and lids provide essential entry points for and of grease traps. These are usually sealed manholes equipped with to prevent odor escape and infiltration, ensuring the trap remains airtight and secure. While basic gravity grease traps rely on the aforementioned components for separation, optional add-ons such as coalescing media or screens can enhance grease capture in certain designs by promoting the coalescence of droplets, though they are not integral to standard units.

Installation and Sizing

Installation Requirements

Installation of grease traps and interceptors must adhere to established plumbing codes to ensure effective operation and prevent system failures. Hydromechanical grease traps are typically installed indoors, positioned near the fixtures generating grease-laden waste, such as kitchen sinks and dishwashers, to capture contaminants before they enter the drainage system. For configurations where the grease trap serves as the fixture trap, the vertical distance from the fixture outlet to the trap inlet shall not exceed 30 inches (762 mm), and the developed length of the waste pipe to the trap shall not exceed 60 inches (1524 mm). However, for optimal grease separation, a minimum horizontal separation of 10 feet (3.05 m) from sinks and dishwashers is often required in certain jurisdictions to allow wastewater cooling below 120°F (49°C). In contrast, gravity grease interceptors are generally installed outdoors or below ground level, upstream from the building's sanitary sewer connection, and at least 5 feet from the building foundation to avoid structural interference. Plumbing connections for both types must integrate seamlessly with the existing system. The inlet should connect directly downstream of the contributing fixtures, while the outlet connects downstream to the sanitary drainage line, ensuring no untreated bypasses the device. Venting is required downstream of hydromechanical units to prevent air binding and maintain flow, typically in accordance with general venting standards. Outdoor installations necessitate stable foundations, such as concrete pads, to support the unit and resist shifting due to soil movement or traffic. Units must be primed with water during initial setup to establish proper hydraulic separation of grease. Safety and accessibility considerations are paramount for long-term functionality. All installations must provide unobstructed access to covers and ports for inspection and pumping, prohibiting paving or burial that would impede maintenance. Elevation should be set to facilitate gravity flow and prevent backflow into fixtures, with inlets positioned below fixture outlets but above potential flood levels. For automatic grease removal devices with electrical components, proper grounding is essential to mitigate shock hazards. Professional installation by licensed plumbers is mandatory to comply with local codes and manufacturer specifications. Following placement and connection, systems undergo testing for leaks, proper flow rates, and seal integrity to verify performance before commissioning. Sizing must align with anticipated wastewater volumes, as detailed in separate guidelines.

Sizing Calculations

Sizing calculations for grease traps, or grease interceptors, are performed to determine the required capacity in gallons, ensuring the device can accommodate peak flows while providing sufficient retention time for grease separation. These calculations typically involve assessing the flow rate from connected fixtures, applying a retention time based on the interceptor type, and incorporating a factor to handle surges. Standards such as the & Drainage Institute's PDI-G101 for hydromechanical interceptors and the International Code (IPC) for gravity types guide the process, emphasizing fixture-specific data over generalized estimates. The basic formula for capacity is Capacity (gallons) = Flow rate (GPM) × Retention time (minutes) × Safety factor (1.5–2.0). Retention time varies by interceptor type and application: 2–10 minutes for hydromechanical units depending on grease load (e.g., 2 minutes for low-risk beverage shops, up to 10 minutes for high-fried-food operations), and 30 minutes for gravity interceptors to allow settling. The safety factor accounts for intermittent high flows, such as during peak kitchen rushes, and is commonly 1.5 for moderate surges or 2.0 for high-variability environments. Flow rate is derived from fixture volumes or drainage fixture units (DFUs), with 75% of fixture capacity used as the effective drainage load to account for solids displacement. Fixture-based sizing assigns DFUs to each connected appliance to estimate total flow. Standard DFU values include 2 for a standard kitchen , 3 for a service or prep , 6 for a commercial pot , and 2–6 for dishwashers depending on connection (often combined with sinks). For multi-fixture systems, sum the DFUs and convert to GPM using tables from PDI-G101 or IPC Section 709 (e.g., a 3-inch pipe at 1/4-inch handles approximately 48 DFUs at 58 GPM). Then apply the capacity ; for instance, a with total 72 DFUs (e.g., one pot at 6 DFU, two dishwashers at 6 DFU each, and multiple sinks at 2 DFU each) might yield a 100 GPM flow, requiring per the basic . PDI-G101 and IPC tables provide rated flows for DFU totals, ensuring the interceptor matches or exceeds the calculated rate. In applications, sizing may adjust for meal equivalents to estimate daily grease load and flow, using approximately 1 of per as a baseline for peak-hour calculations. Total meals per peak period (e.g., seats × turnover rate) inform the flow rate, which is then fed into the capacity with retention time. PDI-G101 tables rate hydromechanical units by this flow (e.g., 100 GPM requires a unit with at least 200 pounds grease retention). An example for a high-flow : with 100 GPM peak flow and 2 minutes retention for a hydromechanical unit, capacity = 100 × 2 × 1.5 = 300 gallons minimum, selected from PDI-rated models. This ensures compliance and performance without over- or under-sizing. Additionally, sizing calculations can be performed using dedicated online calculators provided by plumbing suppliers, engineering firms, and municipal resources, which often incorporate standards like PDI-G101 and IPC guidelines.

Maintenance and Cleaning

Routine Maintenance Procedures

Routine maintenance of grease traps focuses on preventive measures to monitor performance and avoid failures, such as backups or overflows, through regular observations and minor interventions. These procedures help ensure the trap effectively separates fats, oils, and grease (FOG) from without requiring full cleanouts. Visual inspections form the core of routine upkeep, typically conducted weekly to detect early signs of issues. Operators should check for unusual odors, signs of backups, or overflows around the trap, which may indicate accumulation or malfunction. Additionally, monitor the depth of the layer using a measurement tool; if it exceeds 25% of the total trap depth, initiate cleaning to prevent grease escape into downstream systems. Employee practices play a vital role in minimizing grease trap loading and supporting long-term functionality. Install and maintain strainers on all drains to capture food solids before they enter the trap, reducing sludge buildup. Staff must avoid pouring grease, oils, or hot liquids directly into sinks, instead directing such waste to designated collection containers for proper disposal. Maintaining logs of cleaning and maintenance activities helps track performance and comply with regulations. Basic servicing tasks include periodic checks to maintain trap integrity, such as pumping out accumulated quarterly if inspections reveal significant buildup beyond routine levels. Test for clarity by observing for visible particulates or , which signals incomplete separation and potential need for adjustment. Always ensure trap covers are tightly secured after any access to contain odors and prevent unauthorized tampering. Essential tools for these procedures include a or core sampler for accurately measuring and levels without full evacuation. Full cleaning schedules, including major pumping, are addressed separately based on observed needs from these routine checks.

Cleaning Frequency and Methods

The frequency of cleaning grease traps is determined by the volume of fats, oils, and grease () generated, with industry standards recommending intervals of to 90 days to prevent overflows and maintain functionality. For high-use establishments such as restaurants with frequent operations, monthly is often necessary, while lower-volume sites may extend to every three months; however, must occur before accumulation reaches 25% of the trap's total capacity to avoid violations and backups. Professional cleaning protocols involve a systematic process to fully restore the trap's capacity. The procedure begins with draining the contents using a to remove FOG, solids, and , typically handling 500 to 2000 gallons depending on the trap size. Baffles and interior surfaces are then scraped to dislodge adhered buildup, followed by an inspection for structural damage, , or leaks; any issues are noted for repair. The trap is then rinsed thoroughly with or an enzyme-based cleaner to remove residue, and all components are rinsed before reinstallation to ensure proper sealing. Cleaning must be performed by licensed haulers who comply with local regulations, including the use of manifests to document waste volume, transport, and disposal destination for . These services track exact volumes removed during each clean to inform future scheduling and ensure adherence to capacity limits. Post-clean verification includes a flow test to confirm unrestricted passage and a check of seal integrity to prevent leaks, with all details recorded in logs for compliance audits by authorities.

Applications

Commercial and Industrial Applications

In commercial settings, particularly restaurants and food service establishments, grease traps are mandatory installations to manage from kitchen sinks, dishwashers, and food preparation areas, capturing fats, oils, and grease (FOG) before it enters municipal sewer systems. Requirements vary by local regulations and . These devices are required for facilities producing significant FOG-laden , such as those serving over 1,000 meals per day in some areas, where sizing is based on factors such as peak flow rates or meal volumes, following local guidelines. For instance, high-volume restaurants often require interceptors of 1,000 gallons or more to handle demand without overflow. In industrial contexts, grease interceptors are essential for high-volume operations like food processing plants, hotels with on-site kitchens, and cafeterias, where multi-unit or multi-interceptor setups are often deployed to address diverse FOG sources across production lines. Breweries and meat packing facilities, for example, integrate these systems to treat wastewater from cleaning processes and rendering areas, with case-by-case approvals allowing multiple interceptors to handle segmented flows from brewing vats or slaughter lines. Such configurations ensure compliance with pretreatment standards by isolating FOG from solids and integrating with broader wastewater management. At scale, grease traps in commercial and industrial applications significantly reduce the risk of overflows (SSOs). Grease is responsible for 47% of sewer blockages and overflows (per EPA), and properly maintained traps help mitigate these risks by capturing that could otherwise cause blockages. They integrate seamlessly with pretreatment systems, lowering maintenance costs for sewer infrastructure and protecting treatment plants from accumulation that leads to corrosion and odors. Case examples illustrate their efficiency in fast-food chains, where automatic grease removal units (AGRUs) have been adopted for streamlined ; for instance, a location in upgraded to a Grease Guardian D3 automatic grease removal device in 2023 to automate collection and reduce manual pumping frequency, aligning with broader programs that emphasize compliance and . Similarly, a chain implemented grease trap enhancements to cut levels, supporting municipal programs that monitor and enforce trap performance in high-traffic outlets.

Residential and Other Uses

In residential settings, grease traps can be used in kitchens, particularly under the , to manage fats, oils, and greases () generated from frequent cooking activities such as frying or preparing greasy meals, though they are not typically required. These compact units intercept FOG before it enters the household , thereby reducing the risk of in and protecting septic systems in rural or off-grid homes where municipal sewers are unavailable. For instance, households relying on septic tanks may benefit from these traps, as they prevent excessive grease accumulation that could otherwise lead to system failures and costly repairs. Beyond homes, grease traps find application in institutional and mobile environments, including schools and hospitals where cafeterias produce moderate volumes of FOG-laden , as well as on marine vessels to comply with onboard requirements. In schools, these devices help maintain hygienic drainage in dining areas, while hospitals use them to safeguard in food service operations. Portable variants are particularly suited for food trucks and temporary setups like campsites, allowing for easy transport and connection to low-flow drains to capture FOG without permanent infrastructure. These residential and niche applications typically involve smaller grease traps with capacities ranging from 5 to 20 gallons, designed for low-flow rates of 5-15 gallons per minute, which accommodate intermittent use rather than continuous high-volume discharge. Installation often emphasizes simplicity, with many under-sink models supporting DIY setups using basic connections, provided local codes permit, to minimize disruption in space-constrained areas. However, users must account for frequent manual cleaning due to the limited retention volume. Emerging uses in eco-friendly homes integrate grease traps with systems to promote sustainable management, where kitchen effluent is pretreated to remove before reuse in or subsurface dispersal. This approach is common in off-grid or tiny home designs, enabling the diversion of treated away from septic systems while adhering to environmental standards that require grease separation to prevent . Such integrations enhance by up to 50% of household , though they necessitate compatible biodegradable products to avoid system fouling.

Byproducts and Management

Brown Grease Characteristics

Brown grease, also known as trap grease, is the byproduct recovered from grease traps that capture fats, oils, and greases () from wastewater, primarily in commercial kitchens and food processing facilities. It consists of a complex mixture of fats, oils, greases, , water, and sometimes detergents derived from wastes. The composition varies by source but typically features high levels of free fatty acids (FFAs), often exceeding 15% and reaching up to 61% of the fraction due to hydrolytic degradation during accumulation. Triglycerides form the primary component, alongside polar lipids and neutral lipids, with solids content ranging from 0.9% to 8.2% and ash from 1.5% to 9.1%. Physically, brown grease exhibits a semi-solid or greasy texture at room temperature, transitioning between and states depending on its profile and temperature. It is notably odoriferous owing to the breakdown of organic components into volatile compounds. typically measures around 0.86 g/cm³, reflecting its -rich nature, while varies significantly based on FFA content and source, often requiring heating for handling. Due to its high lipid concentration, brown grease holds substantial content, approximately 17,000 BTU/lb on a dry basis, making it suitable for conversion to biofuels like . Brown grease accumulates as the buoyant top layer in grease traps, where reduced flow velocity allows FOG to separate from via flotation. This process distinguishes it from , which is cleaner used with lower FFA levels (<15%) and minimal solids contamination, rendering brown grease more degraded and impure. Generation volumes are variable but significant; in the United States, brown grease production is estimated at 1.5 million metric tons annually, largely from urban food service operations. In commercial kitchens, FOG concentrations in untreated wastewater average 100–200 mg/L, representing a minor volumetric fraction of total flow yet posing challenges for separation and management.

Disposal and Recycling

Brown grease from grease traps is collected by certified haulers using specialized trucks or portable sealed containers to prevent spills and odors during extraction and initial handling. These haulers must be registered with environmental agencies, such as the Texas Commission on Environmental Quality (TCEQ), and transport the material in dedicated compartments to avoid mixing with other wastes. A required manifest accompanies each load, documenting the generator, transporter, and destination facility to ensure traceability and compliance during transit. For short-term holding before transport, brown grease is stored in approved, watertight tanks or drums that meet local regulatory standards to minimize leakage risks. Direct discharge of brown grease into sewers is strictly prohibited to avoid and treatment disruptions, with violations leading to fines under food service establishment (FSE) ordinances. As a last resort, disposal occurs via at permitted facilities or landfilling after testing for contaminants like , though these methods forgo potential . Preferred management emphasizes to reduce . One key pathway converts brown grease to through acid-catalyzed esterification followed by base-catalyzed , yielding up to 99% from pretreated feedstocks under optimized conditions. If contaminant levels are low—such as minimal pesticides or pathogens—processed brown grease may serve as an additive in , though this use is limited due to quality concerns and regulatory scrutiny. Another viable option is , where brown grease undergoes microbial breakdown to produce , achieving yields of approximately 354 mL CH₄ per gram of (COD) at mesophilic temperatures. Recycling brown grease generates economic value, with biodiesel producers having paid around $0.10 to $0.20 per pound for suitable feedstock, depending on market conditions, offsetting collection costs for haulers and FSEs. Programs diverting brown grease to biofuels or can significantly reduce reliance in participating regions, lowering and disposal fees that otherwise range from $0.25 to $1 per . As of October 2024, partnerships like that between Greasezilla and aim to capture and convert brown grease waste into biofuels, enhancing recycling efforts.

Regulations and Environmental Impact

Regulatory Standards

Grease traps, also known as grease interceptors, are governed by various building codes and standards that mandate their use in facilities generating fats, oils, and grease (FOG). The International Plumbing Code (IPC), in Section 1003.3, requires grease interceptors to receive drainage from fixtures and equipment discharging grease-laden waste, such as kitchen sinks and dishwashers in food service establishments, with specific provisions for design, installation, and restrictions on connections like food waste disposers. Additionally, the Plumbing & Drainage Institute (PDI) Standard G101 establishes testing and certification criteria for hydromechanical grease interceptors, ensuring they meet performance requirements for grease retention efficiency, flow rates up to 100 gallons per minute (GPM), and grease storage capacity based on standardized evaluations. These codes typically apply to commercial kitchens, restaurants, and other food preparation facilities, where installation permits are required to verify compliance with local plumbing authorities. Sizing and installation regulations emphasize flow-based criteria to ensure effective FOG capture without impeding drainage. For food establishments, grease traps must be sized to handle the peak flow rate from connected fixtures, with a common guideline requiring a grease retention capacity (in pounds) of at least twice the anticipated flow rate in gallons per minute, allowing sufficient hydraulic detention time (typically 2 minutes) for grease separation. Installation must position the trap as close as possible to the FOG source, often outside the building or in accessible locations, and include flow control devices to maintain rated performance; permits from local health or building departments are mandatory prior to setup to confirm adherence to these parameters. Maintenance mandates focus on regular servicing to prevent overflows and sewer blockages, with requirements for pumping records to demonstrate compliance. In jurisdictions like , , grease traps must be cleaned at least every 90 days by a permitted transporter, or more frequently if accumulation exceeds 25% of capacity, under local ordinances enforced by departments. Non-compliance, such as failing to maintain management plans or records, can result in fines, service suspensions, or corrective action orders, with penalties varying by jurisdiction under programs like the Clean Water Act. Industrial users are often required to develop comprehensive control plans outlining monitoring, cleaning schedules, and spill response as part of pretreatment programs. Regulatory variations exist across federal, state, and international levels to address local infrastructure. At the federal level in the United States, the Agency's (EPA) National Pretreatment Program under 40 CFR 403.5 prohibits excessive FOG discharges into sanitary sewers, requiring significant industrial users to comply with local limits and pretreatment standards through approved plans. State and municipal codes may impose stricter rules, such as mandatory interceptor sizing for all food service operations. Internationally, the EN 1825 specifies design principles, nominal sizes, performance testing with diesel oil simulations, and quality controls for grease separators, ensuring at least 95% separation efficiency in commercial applications across member states.

Environmental Considerations

Grease traps are essential for mitigating environmental by intercepting fats, oils, and grease (FOG) from , preventing their entry into municipal sewer systems. Well-designed and maintained grease interceptors can achieve up to 95% removal for FOG, substantially decreasing the formation of fatbergs—massive blockages composed of congealed FOG and debris—and reducing the incidence of overflows. These overflows release untreated directly into waterways, introducing harmful pathogens such as and viruses, as well as excess nutrients like and that degrade and threaten and aquatic life. Beyond immediate sewer protection, unmanaged FOG contributes to broader ecological disruptions, particularly in rivers and coastal areas. Overflow events from FOG-induced blockages deliver nutrient-laden that fuels excessive algal blooms, leading to hypoxic "dead zones" where dissolved oxygen levels drop, suffocating and other organisms while altering balances. Conversely, effective grease trap implementation supports sustainability by enabling FOG recycling into , which offsets approximately 74% of lifecycle relative to petroleum diesel, thereby curbing contributions to . In terms of , the of brown grease—the viscous FOG byproduct from traps—has potential to divert portions of the approximately 1.7 million tons produced annually in the from landfills, avoiding production from and promoting production. Yet, lapses in trap amplify risks, with FOG-related blockages accounting for roughly 50% of U.S. sewer issues and imposing annual cleanup and repair costs estimated at $25 billion nationwide. Emerging trends emphasize enhanced ecological integration, including the incorporation of grease traps into green infrastructure like bioretention cells, which use soil and vegetation to further filter and degrade FOG through natural processes, achieving 80-95% pollutant removal. Microbial additives, such as bioaugmented bacteria consortia, are also gaining traction for accelerating FOG biodegradation within traps, potentially minimizing waste volumes and operational demands while fostering more resilient wastewater systems.

References

  1. https://www.portland.gov/bes/preventing-pollution/fats-oil-and-grease/grease-interceptors
  2. https://www.epa.gov/system/files/documents/2023-10/fog-slides.pdf
  3. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-N/part-403/section-403.5
  4. https://www.osha.gov/sites/default/files/publications/OSHA3986.pdf
  5. https://www.ocsan.gov/wp-content/uploads/2024/05/Grease-Interceptors-v20220.pdf
  6. https://nyc-business.nyc.gov/nycbusiness/description/grease-interceptor-information
  7. https://pw.lacounty.gov/epd/industrial_waste/pdf/misc/restaurantpretreatmentguidelines.pdf
  8. https://www.austintexas.gov/department/pretreatment-frequently-asked-questions
  9. https://www.carync.gov/services-publications/water-sewer/sewer/pretreatment/fats-oils-and-grease-control/faq
  10. https://patents.google.com/patent/US306981A/en
  11. https://avantuglobal.com/2020/05/04/history-of-the-grease-trap/
  12. https://www.jstor.org/stable/25029790
  13. https://www.ebay.com/itm/116077764972
  14. https://moongreasetrapcleaning.com/history-of-the-grease-trap/
  15. https://www.greasetrapstore.co.uk/grease-trap-history/
  16. https://schierproducts.com/blog/the-evolution-of-flow-control
  17. https://www.fox16.com/business/press-releases/ein-presswire/827437246/fat-traps-and-fatbergs-the-history-and-consequences-for-nycs-sewers
  18. https://www.aquamundus.co.uk/blog/news/the-history-of-the-grease-trap-where-did-it-all-begin/
  19. https://pcwasa.org/wp-content/uploads/2020/08/PDI-G101-Revised-2017.pdf
  20. https://deltadiablo.specialdistrict.org/files/0ca0a0eed/HydromechanicalGreaseInter.pdf
  21. https://www.zurn.com/content/dam/zurnv49/resources/technical-resources/grease-interceptors/grease-interceptors-engineering-guide.pdf
  22. https://www.deq.nc.gov/environmental-assistance-and-customer-service/fog/bmps-fog2/download
  23. https://precast.org/wp-content/uploads/072825_Products_GravityGreaseInterceptorDesign.pdf
  24. https://webstore.ansi.org/standards/iapmo/ansiiapmoz10012021
  25. https://westchesterlegislators.com/images/committees/2014_2015Term/SEPTIC/2012%20Design%20Standards%20for%20Inter-Sized%20Wastewater%20Trmt%20Sys.pdf
  26. http://www.pdionline.org/grease-removal-devices-grd/
  27. https://www.greaseguardian.com/wp-content/uploads/2024/01/Grease-Guardian-AGRU-Range.pdf
  28. https://standards.globalspec.com/std/544529/asme-a112-14-4
  29. https://www.greaseguardianusa.com/2024/10/04/5-reasons-to-switch-to-an-automatic-grease-removal-device/
  30. https://www.247cateringsupplies.co.uk/ffd-info-centre/buying-guides/grease-traps-everything-you-need-to-know
  31. https://www.buildingincalifornia.com/wp-content/uploads/2014/01/Guide-To-Grease-Interceptors.pdf
  32. http://www.redhookvillage.gov/272/FOG-in-Restaurants
  33. https://pocatello.gov/DocumentCenter/View/131/BMP-Fact-Sheet-PDF?bidId=
  34. https://canplas.com/wp-content/uploads/2024/02/technical-guide-en-endura-specifications-guide.pdf
  35. https://www.pdionline.org/standards
  36. https://cms7files.revize.com/lakeportca/public%20works/sewer/FOG%20Documents/Interceptor%20Whisperer%20Grease%20Interceptor%20Sizing_Selection%20Guide%202018.pdf
  37. https://www.septicblue.com/how-do-restaurant-grease-traps-work.html
  38. https://www.sciencedirect.com/science/article/abs/pii/S0043135422010879
  39. https://ossf.tamu.edu/grease-trap/
  40. https://www.waterboards.ca.gov/rwqcb7/water_issues/programs/pretreatment/docs/intro_fog_inspections.pdf
  41. https://www.newarkohio.gov/wp-content/uploads/2022/08/Gease-Interceptor-How-It-Works.pdf
  42. https://www.dothan.org/DocumentCenter/View/8961/GGI-Design-and-Installation-Specifications
  43. https://www.springfieldmo.gov/DocumentCenter/View/69414/FOG--Mgmt-Plan_2020
  44. https://www.centralsan.org/sites/main/files/file-attachments/approved_materials_list.pdf?1659480130
  45. https://serviceauthority.org/wp-content/uploads/2024/12/FOGMaintGuidelinesContractors02212022.pdf
  46. https://precast.org/wp-content/uploads/041924_Resources_BPGravityGreaseInterceptor.pdf
  47. https://louisvillemsd.org/sites/default/files/inline-files/MSD_FOG_Design_Specs.pdf
  48. https://www.epa.gov/sites/default/files/documents/W6_KyleSorenson_OilAndGreaseTechnology.pdf
  49. https://www.pdionline.org/storage/publications/Guide-To-Grease-Interceptors.pdf
  50. https://codes.iccsafe.org/content/IPC2018/chapter-10-traps-interceptors-and-separators
  51. https://up.codes/s/grease-traps
  52. https://www.fortworthtexas.gov/files/assets/public/v/1/water/documents/grease-trap-installation-guidance-doc.pdf
  53. https://docs.legis.wisconsin.gov/document/administrativecode/SPS%20382.34%285%29%28c%292.b.
  54. https://www.bothellwa.gov/DocumentCenter/View/18638/Appendix-F---Grease-Interceptor-Sizing-and-Selection-Requirements
  55. https://aa.iapmo.org/?code=UPC&chapter=10
  56. http://static1.1.sqspcdn.com/static/f/1395156/27911530/1526888927933/Standard_PDI-G101_revised_2017.pdf
  57. https://ncsd.sc.gov/wp-content/uploads/2020/06/Sizing-Grease-Traps.pdf
  58. https://codes.iccsafe.org/content/IPC2018/chapter-7-sanitary-drainage
  59. https://www.engineeringtoolbox.com/drainage-fixture-unit-values-d_1077.html
  60. https://cms7files1.revize.com/starkcountyoh/Document_center/food-safety/Fats%2C%2520Oils%2C%2520and%2520Grease%28FOG%29/GREASE-TRAP-SIZING-WORKSHEET-1.pdf
  61. https://www.tampa.gov/wastewater/programs/grease-ordinance/education/calculate-grease-trap-size
  62. https://www.centralsan.org/sites/main/files/file-attachments/grease_trap_maint_fact_sheet.pdf?1511394382
  63. https://www.nachi.org/grease-trap-inspection.htm
  64. https://phoenixpumping.com/grease-trap-maintenance/
  65. https://www.bgmu.com/wp-content/uploads/2025/02/Grease-Trap-Maintenance.pdf
  66. https://evergreengrease.com/posts/preventative-measures-for-industrial-grease-trap
  67. https://ace1965.com/2024/12/grease-trap-maintenance-how-to-prevent-grease-trap-clogs/
  68. https://www.sacramentogreasetrap.com/blog/effluent-sampling-testing-grease-interceptors
  69. https://www.usabluebook.com/dipstick-pro-10-ft-long-grease-trap-1-tank-core-sa-64247
  70. https://greaseconnections.com/how-to-clean-a-grease-trap-and-how-often-you-should/
  71. https://www.centralsan.org/sites/main/files/file-attachments/grease_interceptor_maint_fact_sheet.pdf?1511394375
  72. https://www.fcs-inc.org/how-often-should-grease-traps-be-cleaned/
  73. https://www.imperialdade.com/blog/how-to-clean-a-grease-trap
  74. https://www.aldevra.com/articles/cleaning-grease-traps-in-commercial-kitchens-what-you-need-to-know
  75. https://www.mrrooter.com/oneida/about-us/blog/2015/july/how-to-properly-clean-a-grease-trap/
  76. https://www.toronto.ca/services-payments/water-environment/water-sewer-related-permits-and-bylaws/sewers-by-law/mandatory-grease-traps-for-food-service-establishments/
  77. https://www.jea.com/about/wastewater/fats%2C_oils_and_grease/preferred_hauler_program/
  78. https://premiercontractcleaning.ie/how-to-clean-a-commercial-grease-trap/
  79. https://www.mass.gov/guides/nonresidential-septic-system-users
  80. https://files.santaclaracounty.gov/exjcpb1761/migrated/PC_Requirements%2520v07-2023.pdf?VersionId=aw6lyYn3XMFEY.0UF4n7J5jumLgAThzP
  81. https://www.epa.gov/sites/default/files/2017-01/documents/iuinspect.pdf
  82. https://www.miamidade.gov/environment/library/guidelines/fats-oils-grease-control-program.pdf
  83. https://raleighnc.gov/stormwater/services/spot-report-and-stop-water-pollution/fats-oils-and-grease-stormwater-pollution
  84. https://www.greaseguardian.com/2024/02/14/burger-king-grease-guardian-upgrade/
  85. https://qmes.eu/library/case-studies/fog-control-cleaning-in-restaurant-kitchens/
  86. https://todayshomeowner.com/plumbing/guides/grease-trap/
  87. https://www.poophappens.com/the-role-of-grease-traps-in-protecting-your-septic-system/
  88. https://www.southerngreen.com/blog/the-importance-of-regular-grease-trap-cleaning-in-schools
  89. https://www.mahoneyes.com/grease-traps-vs-grease-interceptors/
  90. https://www.greaseguardianusa.com/marine-grease-traps/
  91. https://www.akamaipumping.com/food-truck-grey-water-grease-trap
  92. https://www.homedepot.com/p/8-GPM-Cast-Iron-Grease-Trap-MIF-MI-GO-1/100138583
  93. https://ecoflo.com.au/about-greywater/
  94. https://greywater.net.au/blogs/greywater-blog/greywater-systems-for-tiny-homes-off-grid-living-made-sustainable
  95. https://greenloo.org/greywater/
  96. https://doi.org/10.3390/catal10101189
  97. https://www.nrel.gov/docs/fy20osti/74355.pdf
  98. https://www.diva-portal.org/smash/get/diva2:944380/FULLTEXT01.pdf
  99. https://www.energy.gov/sites/default/files/2024-03/beto-2023-billion-ton-report_3-waste.pdf
  100. https://energy.gov/sites/prod/files/2017/02/f34/biofuels_and_bioproducts_from_wet_and_gaseous_waste_streams_full_report.pdf
  101. https://farm-energy.extension.org/used-and-waste-oil-and-grease-for-biodiesel/
  102. https://www.tceq.texas.gov/assets/public/compliance/compliance_support/regulatory/ossf/TexasRestaurantWastewaterAnalysis.pdf
  103. https://www.tceq.texas.gov/downloads/assistance/publications/rg-389.pdf
  104. https://www.mdpi.com/2076-3298/11/8/159
  105. https://www.mdpi.com/2073-4344/10/10/1189
  106. https://www.frontiersin.org/journals/environmental-engineering/articles/10.3389/fenve.2024.1354582/full
  107. https://www.biobased-diesel.com/post/brown-grease-smells-like-money
  108. https://www.sciencedirect.com/topics/engineering/brown-grease
  109. https://industrytoday.com/wp-content/uploads/2021/11/Value-of-Brown-Grease-for-the-Biofuels-Industry-Greasezilla-Whitepaper.pdf
  110. https://greasezilla.com/merging-net-zero-with-zero-waste-press-release-cloned/
  111. https://codes.iccsafe.org/s/IPC2024P1/chapter-10-traps-interceptors-and-separators/IPC2024P1-Ch10-Sec1003.3
  112. http://www.pdionline.org/pdi-standards
  113. https://codes.iccsafe.org/content/IPC2024P1/chapter-10-traps-interceptors-and-separators
  114. https://www.webstaurantstore.com/guide/503/grease-trap-sizing-guide.html
  115. https://up.codes/viewer/louisiana/ipc-2021/chapter/10/traps-interceptors-and-separators
  116. https://www.houstonpublicworks.org/protect-our-pipes
  117. https://standards.iteh.ai/catalog/standards/cen/c1153b41-58da-4eb4-94b3-f20ba61ebea8/en-1825-1-2004
  118. https://srpmic-nsn.gov/wp-content/uploads/2025/11/FOG-Program-BMP-Sizing-Guidelines-102225.pdf
  119. https://doi.org/10.1016/j.scitotenv.2023.166761
  120. https://green.uw.edu/files/lcy/envh545_wastewater_web.pdf
  121. https://www.susana.org/_resources/documents/default/3-4409-7-1632235529.pdf
  122. https://afdc.energy.gov/vehicles/diesels-emissions
  123. https://www.sciencedirect.com/science/article/pii/S004896972305386X
  124. https://www.researchgate.net/publication/7211808_Sustainable_Oil_and_Grease_Removal_from_Synthetic_Stormwater_Runoff_Using_Bench-Scale_Bioretention_Studies
  125. https://www.mdpi.com/2673-8007/5/4/116
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