History

Excrement Happens
by Rachel, April 1, 1999

Humans began to lead a settled life, growing crops to supplement hunting and gathering, only about 10,000 years ago. For all time before that, humans "deposited their excreta - urine and feces - on the ground, here and there, in the manner of all other land creatures." The soil and its communities (including plants, small animals and microorganisms) captured almost all of the nutrients in animal excrement and recycled them into new components for soil. In this way, the nutrients were endlessly recycled within the soil ecosystem and largely kept out of surface water. As a result, what we call "pure water" is low in nutrients, particularly the major nutrients nitrogen and phosphorus. Because these conditions have existed for a very long time, life in lakes, rivers, and oceans is accustomed to the relative absence of these nutrients. Over the past couple of billion years, life has flourished in this low-nutrient environment, growing complex and interdependent in the process - an aquatic condition we call "clean" and "healthy."

When a body of water is suddenly inundated with nutrients - especially nitrogen and phosphorus - things change drastically. One or a few organisms flourish and begin to crowd out the others. We can all recall seeing a body of water that is pea-soup green from overgrowth of algae. Such a water body is clearly sick, choked, its diversity vastly diminished. Today, much of the surface water of the planet is in a state of ill health because of misplaced nutrients. And a main contributing culprit is misplaced human excreta. Long ago, human civilizations split into two camps regarding the management of excreta. Many Asian societies recognized the nutrient value of "night soil" (as it became known). For several thousand years, and up until very recently, Asian agriculture flourished by recycling human wastes into crop land. The opposing camp, particularly in Europe, had ambiguous feelings about human waste - was it valuable fertilizer or was it a nasty and embarrassing problem to get rid of?

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For many years, coastal cities dumped sewage sludge into the oceans, where it created large "dead zones" that could not support marine life. Other communities dumped their sludge into landfills, where it could pollute their groundwater. Still others incinerated their sludge, thus creating serious air pollution problems, then landfilled the remaining ash or simply heaped the ash on the ground for the wind to disperse. In 1988 Congress outlawed the ocean dumping of sewage sludge. At this point, many communities faced a real waste crisis. There was no safe (or even sensible) place to put the mountains of toxic sludge that are generated every day by centralized sewage treatment systems. It was at this point in history that U.S. Environmental Protection Agency (EPA) - feeling tremendous pressure to "solve" the sludge disposal problem - discovered that sewage sludge is really "night soil" - the nutrient-rich product that has fertilized crops in Asia for several thousand years. EPA decided that the expedient thing to do with sewage sludge was to plow it into the land. Shortly after 1992, when the ban on ocean dumping went into effect, EPA renamed toxic sludge "beneficial biosolids," and began aggressively campaigning to sell it to the American people as fertilizer.