So why, in this growingly competitive business, would a small company rooted in a regional energy cooperative trouble itself with doing things differently? Why would the people behind Philadelphia Fry-o-Diesel LLC dedicate four years of their lives to proving that one particularly sordid variety of waste—restaurant trap grease—can be converted into ASTM spec biodiesel on a commercial scale?
Why? Because trap grease is widely available where they live. And they believe it can be done.
“We believe in using what you’ve got, and what we’ve got is restaurants, Fry-o-Diesel President Nadia Adawi says, explaining that trap grease is cheaper than yellow grease—the recycled vegetable oil that is discarded after making fried foods such as french fries. Yellow grease, unlike trap grease, is already being refined into biodiesel at various plants throughout the United States; it’s also used as an animal feed ingredient. In other words, yellow grease has a market value. Trap grease doesn’t.
However, despite the fact that trap grease is essentially free, there’s a reason biodiesel producers aren’t lining up for it. And perhaps that makes Fry-o-Diesel’s story all the more compelling.
Adawi and her business associates, including Michael Haas, a research chemist with the USDA-ARS Eastern Regional Research Center, have roots in a Philadelphia-based energy co-op simply named The Energy Cooperative. The co-op’s mission is to provide energy cost savings, as well as education and advocacy, on behalf of its members—particularly its low-income, elderly and disabled members—to promote the efficient use of both non-renewable and renewable energy.
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Fry-o-Diesel’s formation conjures up the cliché adage about challenges being opportunities in disguise. Indeed, it was The Energy Cooperative’s own dilemma that led to the creation of Fry-o-Diesel in 2002. At the time, the co-op, which serves thousands of members in the Philadelphia area with renewable electricity and heating oil, was seeking an affordable, renewable alternative to heating oil. Biodiesel—or ”bioheat”—was an attractive option, Adawi says, but it wasn’t produced locally. Trucking in biodiesel (or biodiesel production feedstocks like soybean oil) from the Midwest was doable, but that process seemed to negate the environmental upshot of using the renewable fuel.
And there it was—that adage about finding opportunities within challenges was playing out after all—the idea for Fry-o-Diesel, a company that would produce its own fuel from a locally available waste product, was born.
Four years and an untold amount of intellectual and physical toil later, the company is now on the precipice of making its long-shot plan pay off. Adawi says construction of a 2 MMgy to 3 MMgy commercial-scale biodiesel plant is expected to commence by the end of the year. If that happens, the plant could start up in late 2007. Assuming the project develops as planned, Fry-o-Diesel would be the only source of locally produced biodiesel in the Philadelphia area.
Improving Trap Grease
Disposal Options
The irony of Fry-o-Diesel’s beautiful plan is the repulsive nature of the raw material it’s based on. Trap grease is a waste product in the truest sense. Haas calls it the “the foulest, ugliest” and most chemically challenging crude biodiesel feedstock he has ever brought into his lab. However, that didn’t scare him off, and the scientist’s decade of experience with low-value biodiesel feedstocks has brought a lot to the table for Fry-o-Diesel.
According to the National Renewable Energy Laboratory (NREL), a grease trap works by slowing down the flow of warm greasy water and allowing it to cool. As the water cools, the grease and oil separate and float to the top of the grease trap. The cooler water with less grease continues to flow down the pipe to the sewer. The grease is trapped by baffles, or deflectors, which cover the inlet and outlet of the tank, preventing grease from flowing out of the trap.
The grease, which turns solid at room temperature, must be collected in the trap, or else it congeals on the walls of sewer pipes and restricts flow, explains Debra McCarty, deputy commissioner of the Philadelphia Water Department. To prevent sewer blockage and backflow, food service providers are required by city laws to have their grease traps cleaned out at specific intervals. This service is usually performed by private businesses, such as septic tank service companies, for about 5 cents per pound, according to NREL. By creating value for what is currently a waste product, Fry-o-Diesel’s plan could help both restaurateurs and the city, McCarty says, explaining that grease traps might be cleared more routinely if collecting and disposing of the unsavory material becomes easier and less costly.
Typically, collected trap grease is—or should be—brought to wastewater treatment facilities and processed for landfill disposal. Fry-o-Diesel will harvest the feedstock from traps at restaurants. The company is also negotiating contracts with existing trap grease haulers to have the waste delivered directly to its future biodiesel plant. “Trap grease haulers are thrilled to have a better disposal option for their grease,” Adawi says, adding that restaurants and other producers of trap grease are universally excited to find a use for the waste.
To get a sense of the chemical makeup of the feedstock, Fry-o-Diesel spent a considerable amount of time sampling from traps, trucks and dumping sites. The company discovered that not only is trap grease unpleasant—it’s extremely variable. “We’ve been trying to get a handle on what is typical, and we found there is no such thing as ‘typical’ trap grease,” Adawi explains.
The combination is an assortment of fats, oils and greases (including animal fat, olive oil and vegetable grease), as well as food particles, dirt, water and anything else that falls down drains. The percentage of free fatty acids (FFA) in trap grease varies from 50 percent to 90 percent, although some samples collected by Fry-o-Diesel have come in below 10 percent, according to Process Technology Associates’ Wes Berry, who has been working on the development of Fry-o-Diesel’s process technology for over two years.
Clearly, the primary challenge for this company is tweaking existing process technology to handle this difficult and highly inconsistent feedstock. “By adapting the existing technology and know-how, the technology risks are minimized,” Berry tells Biodiesel Magazine. Fry-o-Diesel uses the same basic steps as conventional biodiesel process technology, but the pretreatment of the feedstock is much more extensive; a methyl ester post-treatment is also involved. Berry says there is as much work involved in pretreating the feedstock as there is in the actual production of the finished product.
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