Sunday, June 28, 2015

EcoPot

As global climate changes, we reconsider the inappropriate technological choices that have led us down this path. As a society, we need to stop digging up and burning fossil fuels and begin to efficiently utilize the natural abundance of sunlight. As individuals, there are three specific techno-mistakes we must, IMHO, let go of – cars, TVs, and flush toilets. This article describes a simple modern replacement for the third of these, the crapper.

Water is beginning to be recognized as a precious resource. Humans are the only land animal that routinely defecates in water, an innovation of urbanization in Europe that was foisted upon the world in colonial days in the name of sanitation. It doesn't make sense today. Besides wasting fresh water, this practice pollutes natural waterways and robs nutrients from the soil. A simple dry composting system restores the nutrient cycle while minimizing pathogens.

People have been crapping on the ground for so long that if we fail to squat for a minute or two each day, our lower backs get tense. The problem is when we live in dense communities, we tend to step in each others' poop before it has a chance to turn into healthy soil. Short circuiting fecal microbes can cause disease, biologically designed to limit our population.

Aerobic composting with an appropriate carbon to nitrogen balance can restore the vital bioculture in soil which can sequester massive amounts of carbon, repairing the damage done by humanity over the last century or so. If we understand this natural cycle and work with it, very little effort is required. A cubic yard of feces composting aerobically will naturally host thermophilic microbes that kill pathogens. Nested in straw, humanure can become soil with no muss or fuss.

I've been imagining the Cascadian Composting Crapper, a dry porta-potty with a strong, lightweight structure, designed to be put in the yard of any home where the residents don't want to use a flush toilet, but prefer to recycle their waste nutrients safely into soil. The CCC can accommodate any number of people indefinitely.

The framework is a welded lattice of 1/4” rebar (almost 50' total) based around a geodesic half of a dodecahedron – 18 edges 18.5” long support 10 triangular faces on a pentagonal base about 4.3' wide. A toilet seat is mounted on the top face. This structure is covered with a fine mesh (22 ft2) to keep insects in and bigger critters out. For privacy the dome is surrounded by a seven pole teepee (1/2” furniture grade PVC tubular poles range from 10' - 16') offset from the dome by 30” rebar ground runners, two of which are doubled to create an entryway. About 368.5 ft2 of light canvass covers the teepee in an involute spiral from about 1' above the ground to 1' from the apex. Two normal people should be able to lift the complete unit and plunge the 6” rebar anchors, which extend downward from each of the five outer poles, into the soil wherever they have prepared a nest of small sticks and straw.

Two of the 16' poles suspend a broad triangular waterproof sheet above the entire structure, which is roughly 12' wide by 12' high. The broad, sweeping roof funnels rainwater (or hose water in a pinch) through a simple mesh filter into a two gallon tank built into the south wall. The tank has a variegated, flat black surface exposed to sunlight to heat the water a bit and gravity feeds into a small wash basin inside the teepee, which drains through a hose fitting outside just tall enough to fit a five gallon bucket under it, so grey water can be stored or used for drip irrigation easily. At initial set-up the prevailing winds are taken into consideration while orienting the entrance, solar tank, and rainwater collection sheet.

The waste chamber is about one cubic yard, cross ventilated through insect proof mesh. The outer shell with no door provides constant airflow to prevent any smell or flies. Ideally, there is a nest of sticks and straw in the bottom of the chamber, which sits on top of the ground, no pit. The design will facilitate aerobic decomposition. Each time a person enters, optionally latching the string with the “occupied” sign, dumps a load, covers with straw, and washes up at the sink.

Besides the sink and toilet, there could be a baby changing hammock and three storage spaces inside. One is for clean diapers, cloth sanitary napkins, and assorted butt rags. There's a removable bin for used cloth (ask about design for the Cascadian Clothes Cycler washing machine) and a space for straw, which is used to cover each deposit in the toilet. Toilet paper is optional. Another option is a magazine rack and a fiber optic solar reading light, but we don't want to get carried away.

The unit is lightweight (probably less than 20 lb) so that when the chamber gets full, it can be lifted off easily. Just drain the water tank, lift the whole thing off the waste pile, sink the anchors around a new nest of sticks and straw, and hose it down if you want to. Within six months without any further attention the old pile will be usable topsoil. An attentive observer will note that the pile gets warm, similar to fever in eliminating pathogens. If dogs or other critters might dig in it, you could set a second mesh dome, without seat, sink, or teepee, (24.5 ft2 mesh + 30' rebar) around the pile as it works naturally.

The soil built with the EcoPot is ideal for no till permaculture. When you move the dome off, as weeds begin to set root, you can plant the pile with a collection of compatible vegetables seasonally appropriate for your location. For example, I might plant spinach, onions, beets, cabbage, carrots, strawberries, and tomatoes, mixing seeds randomly. Soil should always be covered with diverse plants or mulch. If you can see bare soil, the microbes in it are starving. Healthy soil will absorb floods, withstand drought, and sequester carbon from the atmosphere, but the microbes need a constant diet. 

Building and using a composting toilet is one important step toward a world that will provide for our progeny. Together we learn to grow our own food, pedal our own bikes, and care for our neighbors.

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