Free sludge to good home
Concerns grow over chemicals in fertilizer
Since 1993, the U.S. Environmental Protection Agency has helped cities across America deal with their mountains of sewage by allowing them to chemically treat the sludge and pass it off as fertilizer.
On the surface, recycling sewage sludge seems like a great idea. When treated properly, it can make a nutrient-rich fertilizer for crops, flowers and plants.
About 60 percent of all the sewage sludge, 5.6 million tons dried out, is spread on farms, yards and fields nationwide each year.
Now, Atlanta is set to jump on the fertilizer bandwagon. Starting in October 2006, the city plans to give out free treated sludge to city residents to sprinkle on their gardens and lawns.
In a 10-year, $200 million sewage recycling deal signed back in August, USFilter Operating Services will build and manage two sewage recycling plants. Construction begins next year.
But the city's ambitious plans come amid a growing chorus of opposition from environmentalists, academics and within the EPA itself to using treated sludge as fertilizer — even sludge treated to the EPA's highest standards.
In terms of chemical contaminants, Class A sludge is tested for levels of nine heavy metals — arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium and zinc. But it's the contaminants that aren't tested for that worry scientists. Dioxins, a family of chemicals not tested for in sludge, are carcinogenic; they don't break down in soil and can be absorbed by plants and through contact.
Currently, the city of Atlanta allows businesses and industries to flush their wastes into the city's sewage system. First, though, the industrial waste has to be brought up to clean water standards. When the new system is up and running, that industrial waste will be combined with human waste, and the mix will be processed, dried out and turned into pellets.
"We made a choice to plumb industry down the same drain as our domestic wastewater and there are obviously many more chemicals that are in sludge than these nine [heavy metals] that are regulated," says Ellen Z. Harrison, director of Cornell's Waste Management Institute. "We even have questions about the protectiveness for those nine metals. We believe they are not adequately protective so we've called into question [using Class A sludge] for home gardening use."
Harrison has testified before Congress about the dangers of using sludge as a fertilizer and helped author a National Academy of Sciences report released in July. The investigation found that EPA's standards were developed using faulty data and outdated methods, and criticized its lack of oversight.
The report said the EPA relied on a 1988 sludge survey when it picked the nine chemicals it chose to regulate. Since then, new chemicals of concern have been identified in sludge, such as flame retardants and pharmaceuticals, the report says.
Harrison says there isn't sufficient outcry against the Class A sludge because "you're unlikely to see the health effects tomorrow, unlike the heath problems related to pathogens where someone is going to get sick."
Even people within the EPA say the current standards aren't protective enough.
David Lewis, who works in EPA's National Exposure Research Laboratory in Athens, says Class A sludge can irritate the skin, mucus membranes and respiratory tracts.
Lewis' criticism of EPA's sludge standards almost got him fired from the EPA. But he fired back with a lawsuit and remains on staff, so far.
Despite the questions surrounding recycled sludge, Mayor Shirley Franklin is enthusiastic about the prospects of the deal. "This public-private partnership will allow the city of Atlanta to maximize the environmental benefits of biosolids. Hopefully, we will take advantage of the opportunity to enhance the beauty of our communities by using biosolids to fertilize our gardens, lawns and plants."
Franklin, it should be noted, once worked as a consultant for USFilter. In 1998, she helped negotiate a deal between Atlanta, Fulton County and USFilter to construct a new water treatment plant. Her business at the time, Urban Environmental Solutions, had a 12.5 percent interest in USFilter's bid, which the company eventually won.
A spokeswoman from the mayor's office says Franklin's work with USFilter concluded in 1999, and pre-dated the company's bid on the sludge contract.