Biosolid Use Nothing to 'Pooh-Pooh'

Biosolid Use Nothing to 'POOH-POOH'
The Journal Gazette (5/20/07)
By Dan Stockman

FORT WAYNE--Is that nutrient-rich fertilizer you’re spreading on your vegetable garden? Or is it toxic sludge, filled with pathogens, heavy metals and industrial waste?

It depends on who you ask.

There’s no question at one point the material distributed in the city of Fort Wayne’s biosolids program was toxic sludge, regulated as a hazardous waste by the U.S. Environmental Protection Agency. But in the more than three years it takes for the sludge to go from the sewage treatment plant to your rose garden, officials say, it becomes a safe additive that is great for plants.

Biosolids are free for the taking if you load them yourself, or for a nominal charge if you have them loaded for you.

“It’s the ultimate in recycling,” said Greg Meszaros, the city’s director of public works. “Lots of communities put it in the landfill or incinerate it.”

“It” is the leftovers of the sewage treatment process. After the sewage is filtered and then run through settling tanks, it goes to digester tanks, where friendly bacteria eat the organic material out of the water. Lest you think this is an insignificant process, consider this: The bacteria are fed 27 tons of solids a day. When the bacteria are settled out, the result is sludge – heavy with water and filled with all the nasty reasons it was flushed away in the first place.

The sludge is then moved to the city’s 55 acres of drying basins, where it spends three years drying out and being turned to increase exposure to oxygen. State and federal law then requires testing for heavy metals and pathogens to ensure the material is safe before being distributed.

“We take our permit requirements very seriously,” Meszaros said. “That’s something we’re not just going to pooh-pooh.”

City officials say there is little risk from biosolids, but Ellen Z. Harrison, director of the Cornell Waste Management Institute at Cornell University in Ithaca, N.Y., said she cautions people not to use the word “safe.”

“With pretty much everything, the question is, is it an acceptable risk?” Harrison said. “The question of acceptable risk varies from person to person.”

So how does she view biosolids?

“My perspective on the use of sewage sludges in residential settings is there are a number of known and unknown risks that would lead me to personally not use this material,” she said.

Failed tests, state scrutiny

Even following state standards can be challenging, officials said.

The city halted biosolid distribution for nearly a month after the state sent a notice saying the city had violated its permit. Distribution was supposed to resume Friday, but test results did not arrive. The program is expected to resume Monday if test results are available and indicate the material is safe.

Those trying to get biosolids Friday were turned away from the site, a sun-baked parking lot surrounded by piles of brush and grass clippings with a mobile home for an office and two vehicle scales.

The state warning was based on the city’s annual report to the Indiana Department of Environmental Management submitted Jan. 30, which showed that biosolids in January and June of 2006 had elevated levels of fecal coliform but were distributed anyway, and that in May there were too many heavy metals in the soil. State officials also had questions about dates and weights of materials that were unclear in the city’s annual report.

An April 26 response from the city says the failed heavy metals test was because of an improperly calibrated instrument at the independent testing lab. The biosolids were blended with other soils to dilute the metals to safe levels before distribution, officials said, though that wasn’t clear in the annual report. A second test with a properly calibrated instrument showed the material was safe even before blending, Meszaros said.

The problems with the coliform came from confusion among employees regarding which tests had to be passed, he said. The city’s yard waste plant is run by a private vendor, Fox Contractors.

Meszaros said federal regulations allow plants to test either for salmonella or fecal coliform. The samples in January and June failed the fecal coliform tests but passed for salmonella, so employees thought the material was safe to distribute. The city’s permit, however, is through IDEM, which requires only the fecal coliform test.

“We don’t believe there was any danger in any way to the public,” Meszaros said. “In fact, we don’t believe we violated our permit.”

Because federal rules allow either test to be used, he said, the material met the safety requirements. He also cites rules that allow one of three systems to be used to reduce pathogens; the city does all three – digestion, drying and composting.

Still, to ensure there are no problems, the city temporarily halted the program in late April to ensure all employees are trained and to give officials time to review processes to make sure they are adequate. Although the state requires only an annual report – the notice of violation for the failed tests came more than a year after the first failure – the city will voluntarily submit monthly reports for a year.

“We asked for a comprehensive review,” Meszaros said. “We want to make sure everyone is on the same wavelength.”

Don’t eat dirt, either

City officials insist the biosolids they distribute are safe to use as directed.

But that doesn’t mean you should eat them.

“Use the same common sense that you would with any bagged material at Home Depot or Lowe’s,” said Wendy Barrott, the city’s director of energy and environmental services. And common sense would tell you not to eat, say, composted manure or even just plain dirt out of your yard. Biosolids are not much different from dirt, officials said, only they have more organic matter. They also have all the bacteria and germs that dirt carries.

City officials say the biosolids are similar to topsoil but should really be used as a soil additive, rather than a soil substitute. Because it is so rich in organic matter, they say, it really needs to be blended with top soil for use. The city’s biosolid information sheet recommends putting it on vegetable gardens only once a year. It can also be used on lawns, trees and shrubs.

Resident Julie Cox was planning on using biosolids to help fertilize a struggling flower bed but could not because the program was halted. While the former chemistry teacher would use them in the front yard, she said, she wouldn’t use them where her children play.

“Based on the geography of where we live, they probably don’t have much more heavy metals than what we have in our regular soil,” Cox said of her 75-year-old home. “But I don’t think I would ever use it like, say, in a garden. And I would not use it in the backyard or near the sandbox.”

Critics have said biosolids are just a public relations ploy to help cities get rid of toxic sludge, and cite controversies within the EPA over using the material.

According to the 1995 book “Toxic Sludge is Good For You,” much of the work to spread the use of biosolids was done by the Water Environment Federation, the new name of the Federation of Sewage Works Associations – the national trade group for the sewage industry.

Barrott said that may be true, but that those pushing the use of biosolids are also pushing to ensure they are safe and used properly, through the National Biosolids Partnership ( www.biosolids.org). She also said the EPA responded to the controversy in the 1990s by performing a comprehensive risk assessment, studying everything from the rate plants absorb toxics out of the soil to all the possible routes humans could be exposed to pollutants.

“All the numbers were set very carefully by the EPA,” Barrott said. “They want to make sure your processes (for removing harmful materials) are really robust.”

In addition, officials said, there should be little or no pollutants in the biosolids because they are taken out of the waste stream before they ever get into the sludge biosolids are made from.

The city has an industrial pre-treatment program that requires industries to remove chemical pollutants from their sewage before it goes into the sewer lines. Officials said that protects the friendly bacteria at the treatment plant, the Maumee River where the processed wastewater is released, and eventually the users of biosolids.

The Waste Institute’s Harrison, however, said that industrial pre-treatment does not remove all pollutants – and chemical pollutants are not removed at the sewage plant.

“It’s a tremendous overstatement to suggest (industrial pre-treatment) has taken care of all the industrial contaminants in sludge,” Harrison said. “Why should I put industrial waste on my property?”