Composting Toilets and Beyond
Managing feces and urine has been a focus of civilizations for thousands of years. All over the world people have developed systems from as simple as digging a hole in the ground, or using running water to carry it away to a river or stream, to complex interconnected cities of underground pipes that end in sewage treatment facilities. In Asia it is common to recycle feces and apply it back to agricultural ground as “Night Soil”, while in America and Europe it is commonly referred to as “Waste” and thought of only in disgust. Feces and urine definitely should be considered carefully, as feces in particular can harbor dangerous or potentially lethal viruses and bacteria. Handled properly, however, human as well as other animal “Waste” can be recycled through the various processes of nature or applied science.
Advancements in sanitation and hygiene practices are often cited as an integral factor of recent global population boom. Modern western plumbing employs a drain-waste-vent system removing sewage and greywater from a building and venting gases produced by the waste. Running water carries away the waste and joins with a central sewage system often leading to a central sewage treatment plant and eventually a landfill. As the population continues to rise, the feasibility of using more water and land to divert human waste will become more difficult and ultimately fall on the shoulders of a future generation to determine how to reclaim these currently untapped unwanted resources. Over one billion people currently live without consistent access to running water or electricity. Composting toilets offer one alternative, but not without their own drawbacks, and further advances in environmental engineering and chemical engineering are allowing for greater technological advances in the capture and processing of human waste.
The compost toilet can either collect urine and feces together
or separately. If collected separately, the urine may be used directly as
fertilizer or channeled into a small wetland or marshy plant bed to evaporate
or be absorbed. Feces collection can be as simple as using 5 gallon buckets and
swapping them out as the buckets are filled. Some composting toilets have two
or more large collection chambers and when one is full it is closed off while
the second chamber is then used for collection. The closed collection chamber
often remains sitting for a year or more before being used as compost.
Generally the smaller the chamber for collection there is more likely a greater
need for a separately located compost pile.
Some composting toilets try to employ external heat, either
via the sun or electronic heating systems, to dehydrate the fecal collections. The
dehydrated feces often need additional composting to be made useable. Every
year the Bill and Melinda Gates Foundation offer a competitive grant to groups
designing innovative toilets requiring no running water or externally generated
electricity. The winning group in 2014 is from the University of Colorado
Boulder 2014 and was awarded $770,000 for a design that uses concentrated solar
energy to convert collected feces into biochar.
Whether you use a simple 5-gallon bucket to collect your
human waste or a high tech solar toilet to convert into biochar, the design of
the modern toilet will eventually have to change. Fresh drinkable water is a
precious resource that should eventually be excluded from human waste management.
The composting toilet provides the opportunity to turn human waste into fresh
vegetables.
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