Tuesday, August 25, 2015

Civilization and Sludge

The emergence of domestication and agriculture allowed humankind to produce more food per area of land, but this innovation also resulted in myriad unintended consequences, many of which were unsustainable.  One of my favorite essays is Civilization & Sludge, by Abby A. Rockefeller.  It describes the evolution of how people dealt with the production of human excrement, a process that never ends.  Like everything else in the human saga, the history begins simple and sustainable, and over time degenerates into a system that is complex and energy-guzzling.  The following is mostly a summary of her 16-page essay.

Rockefeller learned that the simplest and most sustainable sewage treatment system was developed by nomadic foragers.  They utilized the same time-proven system used by non-human animals — depositing their feces and urine on the ground, in a widely dispersed manner.  This recycled vital nutrients, cost nothing, required no staff or infrastructure, did not pollute the water, kill the fish, encourage the spread of contagious water-borne diseases, or produce a single spoonful of toxic sludge.  This brilliant system works very well in societies having low population density.

With the advent of agriculture, the supply of food increased, the population increased, the output of sewage increased, and the old system failed completely.  This inspired the clever invention of smelly outhouses and cesspools.  This new technology recycled nutrients less effectively than the nomadic forager system.

The flush toilet grew in popularity during the nineteenth century, as municipal water systems came into fashion.  Municipal water systems increased the production of wastewater, which overwhelmed the old cesspools.  The cheap and dirty solution was open sewers — ditches beside the streets where sewage from the cesspools was drained.  It’s no coincidence that cholera became a very popular disease at this time.

This inspired the development of closed-pipe sewage systems, which moved the wastes out of town — into lakes, streams, and oceans, where nature would (in theory) purify it all.  On the plus side, cholera rates dropped.  On the downside, typhoid became popular among downstream residents who got their water from sewage-laden streams.  Once upon a time, the Thames River of England was filled with salmon, and supported a thriving fishery.  Then came the new and improved sewage systems, which killed the fish, and turned the Thames into one of the most polluted rivers on Earth.

This inspired cities to filter the drinking water pumped from tainted waterways.  Typhoid rates dropped.  But filtering did not remove the sewage from the rivers, and rapid growth in the industrial sector was adding large quantities of other pollutants, including toxics.

This inspired cities to treat waste before dumping it into waterways.  Treatment systems have been evolving over the years — each new design is more complex, expensive, and energy-intensive than its predecessor.  The wastes and nutrients that used to go into the river are now concentrated into toxic sludge.

Because the waste discharged from industry varies from place to place, and day to day, the toxicity of the sludge varies from moderate to extremely poisonous.  The sludge was dumped into the ocean, where the poisons created dead zones on the ocean floor.  Ocean dumping was outlawed in 1988.  At this point, sewage industry propagandists began presenting toxic sludge as a wonderful fertilizer — beneficial biosolids!  This was given to farmers free of charge.  Rockefeller has actually seen stores selling bags of sewage sludge pellets labelled “natural organic fertilizer.”

Toxic sludge is low in nitrogen, so it has to be applied in large quantities to serve as fertilizer.  Heavy metals and other toxins in the sludge move into the soil.  These toxins are absorbed by plants, and the animals that eat them.  In the soil, thousands of industrial chemicals can interact, creating a countless opportunities for unintended and undesirable consequences.

Following the application of toxic sludge at a Georgia dairy farm, the milk was contaminated with high levels of toxic thallium.  Another Georgia farmer watched his herd of 300 cattle die — his free beneficial biosolids happened to contain high levels of arsenic, heavy metals, and PCBs.  Sludge is a hazardous waste.  What do we do with it?  Answer: stop making sludge.  Human wastes need to be returned to the soil, and production of toxic industrial wastes needs to end.

What is the moral of this story?  Thou shalt keep society small and simple.  Ants and bees live well in large complex civilizations.  But humans are not insects.  This is an important fact to remember.

Rockefeller owns Clivus Multrum, a manufacturer of composting toilets.  Other Rockefeller essays:

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