Could Waste Fuel Houston’s Future?
by Charles Stillman, May 2007
The problem of backed-up and overflowing sewage is not exclusive to Houston. The issue costs municipalities across the country millions of dollars every year while creating serious health risks to their residents. Houston is, however, unique in the amount of overflows it experiences. It has the greatest number of sewage overflows – by a factor of four or five - of any other city in the country. Jeff Taylor, deputy director of Public Utilities for the city, reports that Houston's waste water lines average 30,000 obstructions annually. At least 50 percent of these blockages are caused by the accumulation of fats, oils and greases, known collectively as FOG. When FOG enters the sewer system it cools and congeals, forming a solid-like mass that constricts the flow of waste water. If FOG and other debris are not removed from the system, sewage can backup and overflow into
homes and businesses. The Public Works and Engineering department spends some $4 to $5 million a year just unclogging sewers. The city has also been penalized in recent years by the state's environmental agency, the Texas Commission on Environmental Quality, receiving fines in excess of $1 million due to excessive sewage overflows.
Some fifteen years ago the city mandated that certain commercial facilities install grease traps in an effort to curtail the FOG issue. Traps act to separate FOG from the waste water stream by slowing its flow, which allows it to cool and rise to the surface of the trap. There, it is captured and prevented from flowing into the sewer system with the remaining waste water. Although the city forced facilities to install the traps, in contrast to other cities, it never passed any corresponding legislation requiring trap owners to clean them out. A 2005 Health Department survey found that during the course of a year, 60 percent of restaurants either failed to clean their traps or only cleaned them once. Taylor says, "Simply having a grease trap [was] not solving the problem. Grease traps must be maintained to some degree." The same Health Department survey also revealed that 90 percent of the establishments with grease traps were found to be in violation of city health standards.
Earlier this month, the City Council finally passed legislation to address
the FOG problem. The ordinance requires Houston-area restaurants, as well as
car washes and other maintenance facilities, to clean out their grease traps
four times a year. It will also require establishments to pass annual
inspections and obtain yearly permits.
So what is to be done with all the grease that will now be collected from
Houston-area restaurants? Many businesses already have arrangements with a
grease pumping/hauling company to have their FOG vacuumed out of the trap
and carted away. Most haulers usually dispose the trap grease in a landfill.
There are some though, that have come to see value in waste grease, particularly as a source, or feedstock, for biodiesel. For years now, yellow grease, a high quality form of waste grease, has been carted away from restaurants and used to make products like animal feed, soap, and cosmetics. Yellow grease is essentially waste vegetable oil that has been used to fry foods like french fries and chicken. With the push to find less expensive, more sustainable means of producing alternative fuels, companies, including Houston-based Nova Biosource Fuels, Inc., and several municipalities are using yellow grease to produce biodiesel.
This fall, San Francisco will begin to retrieve yellow grease from area restaurants and transfer it to a processing facility where it will be
turned into biodiesel. City officials expect this program to yield 1.5 million gallons of biodiesel per year. San Francisco restaurants currently
have to pay about $45 a month to have their yellow grease picked up by grease haulers. This new arrangement is a win-win for both parties. The city
provides the pick-up service free of charge to the restaurants, while securing for itself essentially cost-free feedstock for biodiesel production
for use in its municipal fleet.
Up to now, trap grease has not been considered for biodiesel production because of its high water content and the amount of impurities it contains. But, due to its low cost and advances in refining, some are beginning to see promise in using trap grease as a feedstock. A company based in Philadelphia called Fry-O-Diesel is building a commercial scale plant with a biodiesel production capacity of 2 to 3 million gallons per year. The company has arranged to suck up the grease from local restaurants and has also negotiated contracts with waste grease haulers to have the grease they collect trucked to its plant.
Another company, North American Biofuels Corporation (NABC), has teamed up with Russell Reid, a wastewater management company that serves over 4,000 customers in the New Jersey, Pennsylvania, and Long island, New York areas, to secure a constant supply of trap grease for use in producing biodiesel.
Even municipalities are involved in efforts to utilize the trap grease in their sewers. Working with the city of Kalamazoo, Michigan, professors at Western Michigan University are producing biodiesel using FOG from the city's restaurants. The Kalamazoo facility can produce as much as 100,000 gallons of biodiesel which they use to fuel a percentage of their city buses.
The city of Rialto, California, has partnered with Chevron Energy Solutions and Fuel Cell Energy to build the nation's first system using FOG to power a hydrogen fuel cell employing methane created from the decomposing waste. The energy created will go to power the town's wastewater treatment plant. The effort is expected to save the municipality $800,000 a year in energy costs.
Houston's recent efforts to deal with its FOG problems will result in greater amounts of recovered trap grease. Mayor White and the City of Houston have shown a commitment to using wind energy and efficiency to reduce dependence on fossil fuels and slow global warming. Diverting trap grease from the city's sewers and from city landfills by using it to produce biodiesel fuel or other forms of energy are other ways Houston can reduce its dependence on fossil fuels while cleaning up the environment.
Photo courtesy of Fry-O-Diesel
