This article concludes Issue 07. See you next month for the launch of Issue 08!
The sewer is the conscience of the city. Everything there converges and confronts everything else. — Victor Hugo, Les Misérables
In his book What is Life? Schrödinger called humans “entropy machines.” Extracting order from our environment to compensate for our disorder, he said, is what defines us as living beings. The same claim could be made of defecation. We strip the world of the nutrients and substrates we need, leaving only waste behind. Yet even though shitting is one of the few universal human experiences, the topic as a whole suffers from euphemism.
What happens in the loo, restroom, garderobe, privy, house of office, necessarium, Gongfermor’s domain, Jakes, close stool, Spanish house, necessary house, water closet, temple of convenience, or house of harkening is seldom discussed, let alone what happens to the material deposited therein. We in the developed world rarely pause to consider the vast and complicated system designed to make the removal of waste a swift and clean experience.
Historically, however, this has not been the case. Nor is human effluent the only component of the vast stream of waste produced by any large collection of people. Our ancestors had to live alongside animal dung and dirt, household rubbish, and the surface runoff from washing, cleaning, or agriculture. This experience has been so unpleasant that the constant need to dispose of, use, treat, or simply avoid the accumulation of waste has been a major driver of innovation. Indeed, rules to limit and control waste disposal have often been cited as the first forms of urban regulation, a rallying point for centralizers and organizers.
At first glance, then, the course of sewage history would seem the triumph of waste removal and sequestration. As cities grow larger, however, the need for innovation and greater resource efficiency has made sewage worthy of further consideration. Scientists and governments have begun to reexamine what valuable resources and data can be found in this brown gold. The Covid-19 pandemic demonstrated the vast potential of wastewater-based epidemiology, while research into the gut microbiome’s influence on human health and behavior continues to burgeon. Engineers have likewise begun to see sewage not simply as a waste stream but as a resource to be mined for valuable elements or even for energy.
Ancient World
The problem of sewage has existed ever since humans began congregating in large numbers. Whereas nomadic peoples could simply leave their waste behind, settlers face the problem of waste build up and removal. For early farmers, however, sewage was not a curse but a blessing.
While prior wisdom held that manure wasn’t used as fertilizer until the Iron Age and Roman times, there is recently discovered evidence that Neolithic farmers spread dung on their fields as early as 8,000 years ago. The limited manure supply was used strategically to nourish more temperamental cereals and pulses such as Einkorn wheat, peas, and lentils, while hardier hull barley crops were left to fend for themselves on more marginal soils.
The use of manure can also be seen in excavations of the Bronze Age town Ugarit in northern Syria, where many of the houses contain a stone-lined pit, containing “potsherds, bones, and flints … [and] human and animal excrement.” Paleoanthropologists have suggested that waste was composted with organic matter in such pits in order to prevent the degradation of nitrogen, phosphorus, and potash by either fungi or their leaching away by slowing down decomposition. Furthermore, in arid climates, manure and excrement oxidize rapidly, losing their fertilizing power. Composting them in covered pits therefore prevented exposure to sun, air, and moisture, helping to retain key nutrients that could later be used to enrich agricultural soils.
... continue reading