Making Modern-Day Night Soil
While the practice of collecting “night soil” from urban households in China to be repurposed as fertilizer in rural rice paddies might be somewhat outdated, the idea of using excrement to maintain soil fertility continues to be promoted by environmentalists around the world.
Over the last fifteen years, humanure has become a more mainstream topic – with community groups throughout the United States urging their neighbours and municipal governments to consider collecting waste and recycling it, instead of using clean drinking water to flush it through our sewer systems. Many eco-minded individuals are even beginning to embrace the concept in their own homes.
“Human waste is a perfectly good source of an important resource, nitrogen,” said Los Angeles-based blogger Erik Knutzen. “Water is a valuable resource, too. Why mix the two and turn all of it into a problem?”
Knutzen was inspired to incorporate a humanure system into his home after reading Joseph Jenkins’ Humanure Handbook: A Guide to Composting Human Manure. The book, currently in its third edition, has been translated into six languages to deliver the humanure message to ecologically-minded city dwellers around the world.
“When properly used and managed, a humanure toilet system requires virtually no water, produces no waste, creates no environmental pollution, attracts no flies, costs very little, requires no urine diversion, and produces no odor,” said Jenkins. “Instead of waste, the toilet produces humus, a valuable resource that can safely grow food for human beings.”
These toilets use organic materials like sawdust, coffee grounds, or peat moss to help eliminate smells, and collect excrement in a bucket that users can then transfer to a compost pile. With additional covering materials like hay, grass, leaves, or pine needles, you can eliminate odours and avoid attracting flies while encouraging microbial activity. Eventually, the compost can be spread throughout the garden as fertilizer.
“The purpose of thermophilic composting is to subject the toilet materials to robust microbial activity, which produces heat generated by thermophilic microorganisms,” Jenkins said. “This process has been scientifically proven to destroy human pathogens, rendering the toilet material hygienically safe and achieving the true essence of ‘sanitation.’”
In fact, the process is similar to the concept of “biosolids,” with some important differences. While biosolids are made up of everything that gets disposed of in sewer systems – including industrial waste like heavy metals, toxic chemicals, and other pollutants – humanure contains nothing but pure human excrement.
Still, the idea of collecting human waste and repurposing it remains an unattractive idea to many city dwellers. Jenkins hopes to change these attitudes through education and eventually, hopefully, the implementation of municipal humanure systems.
“Humanure toilets are not for everyone,” he said. “They are limited to situations where adequate and appropriate cover materials are available. They are a knowledge-based sanitation system and are sometimes referred to as the ‘thinking person’s toilet.’”
However, he added that when the system is properly executed and managed, users will benefit from a low-cost, hygienically safe, environmentally friendly, waste-free ,and pleasant sanitation alternative – and one that also produces a wealth of soil fertility.