We’ve talked previously about how the heat extracted from sewage and wastewater as it flows through pipes is being used to reduce energy requirements associated with heating space or water. But what of the content of those sewage pipes itself? Is there value there?
Despite the yuck factor and centuries of social stigma associated with human waste, the truth is that if you look at the cycle of agricultural production logically it is obvious that removing human waste from the process has led to dire outcomes. As this article from JSTOR states when “we grow our food in location A, but eat and excrete it in location B, we create what scientists call “the metabolic rift”. And because of this gap we end up “replenishing farmlands with chemicals such as synthetic nitrogen—made with fossil fuels and extremely polluting to produce—thus perpetuating this vicious cycle”.
Earlier in human history human excrement might have been applied directly to fields but this is obviously dangerous from a health perspective as well as aesthetically (smell) and largely impractical. But it turns out there are loads of solutions being used all over the world including the Cambi process that is “processing the metabolic output of 114 million people in 26 countries and six continents”.
How is your city or town processing human waste and is there an opportunity to implement something different? As the JSTOR article concludes “if we keep wasting our waste, the earth won’t have the stamina to feed us. The way to close the metabolic rift we’ve wrought is with our metabolic output”.