The Source by Martin Doyle

Author:Martin Doyle
Language: eng
Format: epub
Publisher: W. W. Norton & Company
Published: 2017-02-15T05:00:00+00:00

CHAPTER 8

Burning Rivers

When a toilet is flushed in Durham, North Carolina, John Dodson has to deal with it. Dodson is a gentle giant of a man; tall and broad, but unassuming and patient. Along with wastewater treatment plant operators across the United States, Dodson is always on call, just like a physician with a pager. But when John gets a call from work, the issue involves tens of thousands of people and their unspoken millions of gallons of sewage.

On an average day Dodson supervises the treatment and processing of about half of the wastewater produced in Durham, a city of about a quarter million people. Each day over 8 million gallons of sewage come to his plant—about twelve Olympic-sized swimming pools per day of human waste. Across America others like John Dodson are managing the unseen treatment of human waste: almost 15,000 wastewater treatment plants pepper the country, along with over 700,000 miles of public sewer mains. All of this infrastructure is effectively invisible to the public, assumed to be working sufficiently well to justify being blithely ignored.

The waste from any toilet in Durham is transported through the pipes from the building where it’s housed into larger collection pipes that combine with the many storm sewers of the city. Then it moves on to the sewage main—the large intestine of the city—where, along with the waste in thousands of miles of other pipes connected to countless other homes, buildings, and businesses, the collective waste is routed through ever more miles of pipe and pushed through the pipe system using sixty-six pumping stations spread through the city. Half of this waste eventually reaches Dodson’s treatment plant, which sits innocuously at the edge of town alongside Ellerbe Creek.

The modern wastewater treatment plant is an extension of the work of early twentieth-century sanitary engineers: waste can be naturally processed, given enough time and the right conditions. The right conditions inevitably mean the right microbes, and Dodson is fixated on “the organisms,” as he calls them, for his job is to ensure that the organisms have enough time and the right environment to do their work. When Sedgwick described streams and rivers as “self-purifying,” he was really saying that they naturally contain the necessary microbes to process the waste.

In the early twentieth century, when streams were relied on to purify sewage, it was the distance between cities that made this approach effective. In the time it took for sewage to move from one city to the next along the streams and rivers, the microbes could process the waste. However, as America’s population grew and cities expanded, the distances between communities decreased while the amount of sewage being loaded into the streams increased.

Modern treatment plants use the same fundamental processes to do the work of self-purifying rivers, but they have to do it in much less space. To accomplish this, modern sewage treatment plants use immense tanks that are constantly filling with wastewater. Some treatment plants serving small communities have tanks the size of home swimming pools.

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