David Tenenbaum

Abstract

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The answer is yes. Biosolids are not the same thing as sewage. The sewage treatment process metabolizes raw sewage into a form resembling animal manure. Seven million dry metric tons of biosolids are produced daily ; today, 40–50% of that material is buried in landfills. But some biosolids are recycled on the land.

When applied to the land, biosolids improve the soil's structure, increase its water-holding capacity, and feed its resident microorganisms. Says Robert Brobst, one of the EPA's biosolids program coordinators, "With chemical fertilizers, you are feeding the plant directly. With [biosolids], you feed the soil and the soil feeds the plant."

Biosolids are used to rejuvenate abandoned strip mines, forests, and depleted farmlands. Recycling efforts date back to 1929. In one notably successful program, Wisconsin farmers participate in the Metrogro program, in which they pay a per-acre fee to have their farmlands impregnated with biosolids.

Biosolids recycling is governed by a regulation of the Clean Water Act known as "Part 503." The EPA, while encouraging the recycling of biosolids, uses Part 503 to set strict specifications for allowable levels of toxins, pathogens, and heavy metals in recyclable biosolids. The EPA also regulates where and how biosolids may be recycled.

Concerns have been raised regarding air- and waterborne disease and the odors associated with recycling biosolids. However, there are a variety of application methods that circumvent these problems. Soil, water, and air samples are tested regularly and have, to date, shown no indication of toxic build-up. Furthermore, a review of the literature reveals no scientific evidence that using biosolids on the land causes disease.