Fertilizers Once Marketed

Toxic Metal Flush

Flush Out Toxic Heavy Metals

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Akron, OH

. . . .Akra-Soilite

Battle Creek, MI

. . . .Battle Creek Plant Food

Boise, ID

. . . .B.I. Organic

Charlotte, NC . .

. . . .Humite & Turfood

Chicago, IL . . . .

. . . .Chicagro & Nitroganic

Clearwater, FL . .

. . . .Clear-O-Sludge

Fond du Lac, WI

. . . .Fond du Green

Grand Rapids, MI

. . .Rapidgro

Houston, TX . . .

. . . .Hu-Actinite

Indianapolis, IN .

. . . .Indas

Madison, WI . . .

. . . .Nitrohumus

Massillon, OH . .

. . . .Greengro

Milwaukee, WI . .

. . . .Milorganite

Oshkosh, WI . . .

. . . .Oshkonite

Pasadena, CA . .

. . . .Nitroganic

Racine, WI

. . . .Ramos

Rockford, IL . . . .

. . . .Nu-Vim

San Diego, CA .

. . . .Nitro Gano

San Diego, CA .

. . . .San-Diegonite

S. California . . . .

. . . .Sludgeon

Schenectady, NY

. . . .Orgro & Gro-hume

Toledo, OH . . . .


*Names are registered brand names.

Sources: Rodale, J. I. et al. (Eds.). (1960). The Complete Book

of Composting. Rodale Books Inc.: Emmaus, PA. pp. 789, 790.

and Collins, Gilbeart H.,

(1955). Commercial Fertilizers - Their

Sources and Use, Fifth Edition. McGraw-Hill Book Co., New York

into and concentrate in sewage sludge at wastewater treatment facilities. One study indicated that roundworm eggs could be recovered from sludge at all stages of the wastewater treatment process, and that two-thirds of the samples examined had viable eggs.45 Agricultural use of the sludge can therefore infect soil with 6,000-12,000 viable parasitic worm eggs per square meter, per year. These eggs can persist in some soils for five years or more.46 Furthermore, Salmonellae bacteria in sewage sludge can remain viable on grassland for several weeks, thereby making it necessary to restrict grazing on pastureland after a sludge application. Beef tapeworm (Taenia saginata), which uses cattle as its intermediate host and humans as its final host, can also infect cattle that graze on pastureland fertilized with sludge. The tapeworm eggs can survive on sludged pasture for a full year.47

Another interesting study published in 1989 indicated that bacteria surviving in sewage sludge show a high level of resistance to antibiotics, especially penicillin. Because heavy metals are concentrated in sludge during the treatment process, the bacteria that survive in the sludge can obviously resist heavy metal poisoning. These same bacteria also show an inexplicable resistance to antibiotics, suggesting that somehow the resistance of the two environmental factors are related in the bacterial strains that survive. The implication is that sewage sludge selectively breeds antibiotic-resistant bacteria, which may enter the food chain if the agricultural use of the sludge becomes widespread. The results of the study indicated that more knowledge of antibiotic-resistant bacteria in sewage sludge should be acquired before sludge is disposed of on land.48

This poses somewhat of a problem. Collecting human excrement with wastewater and industrial pollutants seems to render the organic refuse incapable of being adequately sanitized. It becomes contaminated enough to be unfit for agricultural purposes. As a consequence, sewage sludge is not highly sought after as a soil additive. For example, the state of Texas sued the U.S. EPA in July of 1992 for failing to study environmental risks before approving the spreading of sewage sludge in west Texas. Sludge was being spread on 128,000 acres there by an Oklahoma firm, but the judge nevertheless refused to issue an injunction to stop the spreading.49

Now that ocean dumping of sludge has been stopped, where's it going to go? Researchers at Cornell University have suggested that sewage sludge can be disposed of by surface applications in forests. Their studies suggest that brief and intermittent applications of sludge to forestlands won't adversely affect wildlife, despite the nitrates and heavy metals that are present in the sludge. They point out that the need to find ways to get rid of sludge is compounded by the fact that many landfills are expected to close and ocean dumping is now banned.

Under the Cornell model, one dry ton of sludge could be applied to an acre of forest each year.50 New York state alone produces 370,000 tons of dry sludge per year, which would require 370,000 acres of forest each year for sludge disposal. Consider the fact that forty-nine other states produce 7.6 million dry tons of sludge. Then there's figuring out how to get the sludge into the forests and how to spread it around. With all this in mind, a guy has to stop and wonder — the woods used to be the only place left to get away from it all!

The problem of treating and dumping sludge isn't the only one. The costs of maintenance and upkeep of wastewater treatment plants is another. According to a report issued by the EPA in 1991, U.S. cities and towns need as much as $110.6 billion over the next twenty years for enlarging, upgrading, and constructing wastewater treatment facilities.51

Ironically, when sludge is composted, it may help to keep heavy metals out of the food chain. According to a 1991 report, composted sludge lowered the uptake of lead in lettuce that had been deliberately planted in lead-contaminated soil. The lettuce grown in the contaminated soil which was amended with composted sludge had a 64% lower uptake of lead than lettuce planted in the same soil but without the compost. The composted soil also lowered lead uptake in spinach, beets and carrots by more than 50%.51

Some scientists claim that the composting process transforms heavy metals into benign materials. One such scientist who designs facilities that compost sewage sludge states, "At the final product stage, these [heavy] metals actually become beneficial micro-nutrients and trace minerals that add to the productivity of soil. This principle is now finding acceptance in the scientific community of the U.S.A. and is known as biological transmutation, or also known as the Kervran-Effect." Other scientists scoff at such a notion.

Composted sewage sludge that is microbiologically active can also be used to detoxify areas contaminated with nuclear radiation or oil spills, according to researchers. Clearly, the composting of sewage sludge is a grossly underutilized alternative to landfill application, and it should be strongly promoted.53

Other scientists have shown that heavy metals in contaminated compost are not biologically transmuted, but are actually concen trated in the finished compost. This is most likely due to the fact that the compost mass shrinks considerably during the composting process, showing reductions of 70%, while the amount of metals remains the same. Some researchers have shown a decrease in the concentrations of some heavy metals and an increase in the concentrations of others, for reasons that are unclear. Others show a considerable decrease in the concentrations of heavy metals between the sludge and the finished compost. Results from various researchers "are giving a confusing idea about the behavior of heavy metals during composting. No common pattern of behavior can be drawn between similar materials and the same metals . . ."54 However, metals concentrations in finished compost seem to be low enough that they are not considered to be a problem largely because metal-contaminated sludge is greatly diluted by other clean organic materials when composted.55

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