This month, BlackGold Biofuels, a Philadelphia-based company, turned an 800-pound butter sculpture into diesel fuel. It was part of an experiment led by Michael J. Haas, a research biochemist at the United States Department of Agriculture (USDA). The sculpture, shaped like Benjamin Franklin and the Liberty Bell, was made for the Pennsylvania Farm Show.
BlackGold doesn’t usually work with rancid butter; the company specializes in turning fats, oils, and grease–known in the cooking industry as FOG–into biofuel. FOG, also called brown grease, is more commonly comprised of used cooking oils or sewer grease. Brown grease is typically disposed at sewage treatment plants and then transferred to incinerators or landfills. BlackGold has developed and demonstrated the process of converting FOG to biodiesel at its pilot-scale plant in Philadelphia.
Now, BlackGold is working with San Francisco’s public utilities commission (SFPUC) to operate a biodiesel plant there, which, when completed, is expected to extract 330 gallons of biodiesel a day out of 12,000 gallons of wastewater. Getting rid of FOG in the city’s sewers has been an ongoing problem for the city; San Francisco spends upwards of $3.5 million annually responding to grease-clogged pipes, due in large part to its popular restaurant trade. Earlier this year it was estimated that nearly four million gallons of FOG are released into the wastewater system each day.
The SFPUC has already passed a law requiring restaurants and other food-serve establishments meet limits for the amount of grease and oil that can be discharged into the city’s sewer system. And restaurants must also install grease traps that block sewer-blocking compounds with full compliance expected by mid-2012. Some establishments are also testing out automated grease-removal machines that separate out fats, oils, and grease from solid food waste so the solids can be composted and the grease recycled and then turned into biofuel.
According to the SFPUC, the city is currently running tests of brown grease using BlackGold technology at its Oceanside Water Pollution Control Plant, and the agency is hoping to have the plant up and fully functional within the next few months.
Article by Julie Mitchell, appearing courtesy Celsias.