Food Rights Network

Sewage Sludge in the News

November 1, 2011

• “Summit County digester gets $2 million federal grant”: According to the Beacon Journal (Ohio, 10/28), Sen. Sherrod Brown (D-Ohio) announced the USDA grant to Lime Lakes Energy LLC in New Franklin, Ohio. The facility will ferment high-solids sewage sludge, as well as food waste and grease, using bacteria that do not need oxygen, producing methane to be used as compressed natural gas. Sounds good so far, right? “Leftover wastes from the operation will be used to speed up the reclamation of Lime Lake 6 by PPG Industries.” Using digested sludge for “reclamation”? Sounds a little bit like spreading sludge on the lawns of Baltimore families in poor neighborhoods to see whether or not it cleans up lead.
• “Metal stress and decreased tree growth in response to biosolids application in greenhouse seedlings and in situ Douglas-fir stands”: A study to be published in the January 2012 volume of Environmental Pollution (but available online 10/14) found that “phytochelatins – bioindicators of intracellular metal stress – were elevated in foliage of biosolids-amended stands, and significantly higher in roots of seedlings grown with fresh biosolids. These results demonstrate that biosolids amendments have short- and long-term negative effects that may counteract the expected tree growth benefits.” Highlights include:

► Biosolids amendment increases soil metals over 25 years later.
► Douglas-fir growth benefits fail to materialize from biosolids amendments.
► Phytochelatins are elevated in foliage of trees and roots of greenhouse seedlings after new biosolids are added to soil.
► Biosolids connected to metal stress in Douglas-fir.

• Digested Sewage Sludge Dewatered Using a Centrifuge can Experience Sudden Increase in Bacteria: According to the abstract of this research article in Water Environment Research (published by the sewage sludge industry trade group, the Water Environment Federation, September 2011), “Several investigators have reported higher densities of indicator bacteria after dewatering of anaerobically digested biosolids. The increases appear to occur at two points in the biosolids process: the first, referred to as ‘sudden increase’, occurs immediately after dewatering; the second, ‘regrowth’, occurs during storage over longer periods. The objectives of this study were to examine the effect of digestion and dewatering processes on sudden increase and regrowth of fecal coliform and E. coli.” (Thanks to Maureen Reilly of the Sludge Watch Working Group for pointing this one out.)

Filed under: In the News,Sewage Sludge