San Francisco’s pipes are clogged with FOG—but not the white misty stuff of postcard fame. FOG stands for the fats, oil, and grease dumped down the drain every day by restaurants and residents, which can clog sewer pipes and lead to unsanitary backups, street overflows, foul-smelling odors, and costly damage to sewer infrastructure.
All of this backed-up grease jamming the city’s arteries is taking a heavy toll on the heart of its century-old sewer system, which is nearly at the end of its expected life span. In 2006, the San Francisco Public Utilities Commission (SFPUC) estimated that it received about seven calls a minute due to complaints about fat-clogged sewer lines. The agency says that the city has been spending about $3.5 million a year to clean up sewers blocked by oily wastes illegally or irresponsibly dumped by commercial and residential kitchens. Additional “hidden” costs include lost business (such as when a restaurant can’t operate because of a sewer backup), and expenses to the city’s Health Department, including the rather grim possibility that it will boost the rat population by giving them a food supply. Another problem: in San Francisco, unlike other cities around the bay, storm water and sewage share the same piping. These grease-constricted sewer lines are apt to overflow during winter storms.
Can this organic waste problem actually be a solution to the city’s insatiable need for renewable, clean sources of energy? The PUC thinks so. Its new SFGreasecycle program aims to prevent grease from entering the sewer system in the first place, instead turning it into biofuel. Karri Ving, coordinator of the program, puts it this way: “The best solution is to stop pollution at its source.”
To this end, SFGreasecycle offers restaurants, hotels and schools with large kitchens free collection of waste vegetable oil. The program provides 55-gallon collection drums for high-volume kitchens and encourages the smaller ones to reuse the five-gallon containers the oil originally comes in. SFGreasecycle educates kitchen staff about how to avoid mixing food scraps or water into the waste oil, and about why it’s wiser to use pure vegetable oils than partially hydrogenated ones. (The program may be expanded to collect the waste that winds up in restaurants’ grease traps, which usually contains more animal fats.)
Currently, the program dispatches trucks to pick up vegetable oil and tote it to a transfer facility at the city’s southeast sewage treatment plant. There, the waste oil is filtered and shipped to one of four companies for conversion into biodiesel. SFGreasecycle is also responsible for storing the biodiesel, which will be used to fuel city vehicles.
The program fits neatly with some of the city’s larger environmental goals, including reducing the city fleet’s reliance on petroleum, promoting green practices, and preventing social inequities like allowing waste to be offloaded to landfills in disadvantaged communities. “The only drawback to this program is that we should have been responsibly doing it fifty years ago,” says Ving, who credits “really strong mandates from the top” for pushing it forward.
Specifically, she means directives from Mayor Gavin Newsom, who ordered that by the end of 2007 all city-owned diesel vehicles would be running on a mixture called B20, which contains at least twenty percent biodiesel. The city met that goal and is now required to increase the percentage of biodiesel used, ideally to 100 percent. Currently, most of the city’s biofuel is supplied by San Francisco Petroleum. Although the company is required to buy preferentially from local sustainable biodiesel companies when it can, there’s just not much nearby supply. Instead, San Francisco Petroleum largely produces its biofuel from virgin vegetable oil transported from the Midwest.
Ving hopes this will change in mid-2009, when the city’s three-year master fueling contract is up for renewal. The SFPUC’s new contract is expected to include more stringent requirements for use of local biofuels. While SFGreasecycle can meet some of this demand, the market opportunities opened up by the new contract may also help spur competition among public and private companies for production of alternative fuels.
SFGreasecycle will also provide a springboard for the SFPUC to address other conservation and social equity issues. There are plans for SFGreasecycle to provide education, internships, and jobs, particularly targeting less economically advantaged neighborhoods, such as Hunter’s Point. Ving says the utility may partner with nonprofits, such as Goodwill, and with community colleges to help residents develop job skills and safe, well-compensated employment. In addition to jobs in biofuel production, there are other training opportunities—for example, interns can earn their Class A drivers’ licenses while transporting waste vegetable oil and biodiesel.
The idea that every sewage system can become an energy conservation facility is precedent-setting, and an all-encompassing program like SFGreasecycle is still unique to San Francisco. “No other city is setting a goal to direct all of its organic food waste into biofuel,” says Ving. She hopes that SFGreasecycle can become a model urban zero waste program, not only for US cities, but throughout the world. She notes that many towns—from developed nations to third-world countries to remote places like the Amazon—have trouble both with importing fuel and disposing of their waste. Turning fat into fuel could be an elegant solution to both problems.
