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4 Profit vs. Purification: “Sewage Is Something to Be Got Rid Of”1 In 1927, the Milwaukee Sewerage Commission took to the airwaves to publicize an “epoch making achievement.” “For the first time in the history of sanitation,” the radio broadcast claimed, “the valuable plant food elements contained in sewage and trade wastes are being converted into a marketable fertilizer.”2 The Milwaukee fertilizer project was “being watched in all parts of the world,” the Sewerage Commission declared. This was not hyperbole. Sanitary scientists internationally were paying rapt attention to Milwaukee’s experiments in turning sludge into fertilizer, for they revived hopes held since the early days of sewage treatment that sewage could “be converted into gold.”3 For almost sixty years, sanitarians had been pursuing the idea that the nutrients retained in domestic and industrial waste could make sewage treatment pay for itself by recycling sewage sludge into fertilizer. Towns could purify their sewage and make a profit too. Processes were patented, companies capitalized, franchises granted, all with the hopes of making money from sewage. But by 1916, when Milwaukee began experimenting with activated sludge, it had become clear to many, if not most, sanitarians that profit and purification were inherently contradictory goals. It might be possible to make money from sewage, they concluded, but only at the expense of the goal of sanitation. Conversely, sewage could be purified, but cities must expect to pay for it. It was not that sewage lacked valuable components. Rather, the expense of separating the valuable from the worthless was greater than the market value of the sewage. “The valuable constituents of sewage are like the gold in the sand of the Rhine; its aggregate value must be immense, but no company has yet succeeded in raising the treasure,” stated German chemist A. W. Hoffman in 1857.4 Yet when the originators of the activated sludge process measured the elevated nitrogen content of activated sludge, they revived the hope of profitable utilization of sewage. “We have the master key with which to unlock the treasure stored up in sewage sludge,” according to an editorial in the Engineering Record.5 Now, the Milwaukee Sewerage Commission had appeared to finally raise that treasure and was marketing it over the radio “at a very reasonable price put up in 100 lb. bags.” 126 Chapter 4 The “Search for ‘El Dorado’ in the Cities’ Sewers” Beginning in the 1840s, chemists and sanitarians began emphasizing the huge potential value of the fertilizing components of sewage. With the importing of guano from Peru, fertilizer had recently become an important component of farming in Britain. Agricultural chemists like J. von Liebig had developed the idea of limiting nutrients, and emphasized the possibility of artificial fertilizers to maintain soil fertility and increase crop yields, while British chemist John Bennet Lawes had invented and patented a process for making superphosphate fertilizer. These chemical theories, which had replaced earlier vitalistic concepts of soil fertility that emphasized humus, were applied to the analysis of sewage and suggested that the wastes of towns and cities might be worth fortunes.6 The high expectations, on the part of both cities and the firms they contracted with, relied on the chemical analysis of sewage. Applying the conceptual framework of the new agricultural chemistry pioneered by Liebig in Germany and by Lawes and Joseph Gilbert in England, chemists attempted to calculate the fertilizing value of sewage as they had analyzed the value of guano.7 Chemists calculated the concentration of nutrients in feces and urine, measured the volume of excrementitious waste and “fluid voidings”8 of a typical Londoner, and extrapolated huge quantities of nutrients in the sewage of cities. Using these techniques, analysts suggested various values of sewage, based on the equivalent fertilizing power of guano. Estimates ranged from less than 1d. to 2d. per ton of sewage or 6d. to 16d. per person per year. Lawes concluded that “the intrinsic value of the sewage of London, considered in this merely chemical point of view, is therefore enormous,” equivalent to “nearly one-third of the wheat consumed by its population.”9 Other estimates of the monetary value of London sewage ranged from £1,385,540 as calculated by Corfield,£2,793,551 as calculated by Ellis,10 or even £4,081,430 as estimated by Liebig.11 There had already been culturally powerful arguments for recycling sewage on land. The process grew out peasant practices and had its...

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