The Green Cone - How Does It Work?
The system works best in fertile, well-drained soil, which means that areas of solid rock or with a high water table are unsuitable. In heavy clay soils, drainage can be improved by using a mixture of gravel and compost around the digestion basket. Soil fertility can be enhanced by the addition of suitable natural bacteria, as described below.
The smallest and most numerous micro-organisms are bacteria, with one gram of fertile soil containing around a billion bacteria. Bacteria are unicellular micro-organisms and amongst the smallest living creatures known. There are three bacterial cell shapes, spherical (coccus), rodlike (bacillus) and spiral (spirillum). Under favorable conditions bacteria numbers grow rapidly. Some survive in a dormant or spore state when conditions are not suitable, reviving when they become favorable again.
Bacteria are grouped according to their temperature requirements for growth:
Bacteria within each group exhibit specific minimum, maximum and optimum temperatures for growth. For example, mesophiles grow best in the temperature range 77° - 104°F. To ensure a healthy population of bacteria, we recommend the use of our Accelerator Powder when the system is first installed, and if the decomposition process slows because of an imbalance of organic material and bacteria.
Most bacteria grow in a near neutral environment (neither acidic nor alkaline) and without light. Atmospheric oxygen is required by some bacteria, but inhibits others. Bacteria are classified as aerobes when they require oxygen to grow and anaerobes when they cannot grow in the presence of oxygen. Facultative anaerobes do not require oxygen but can grow in its presence; obligate anaerobes are poisoned by free oxygen. Under poor oxygen conditions some micro-organisms can produce toxins that inhibit the growth of higher plants and other micro-organisms. These toxins include methane, hydrogen sulfide, phosphine, skatole, indol and various organic acids. It is for this reason that the Green Cone is designed to maintain aerobic conditions. The temperature gradients in the double walled solar chamber create air movement and ensure these ideal conditions.
In addition to bacteria, other soil micro-organisms are intimately involved in the natural decomposition process. Actinomycetes resemble both bacteria and fungi. Their spores, although similar to those of bacteria, germinate into very fine colorless threads (mycelia) that resemble those of fungi. Fungi such as molds, mildews or mushrooms are usually more variable in form than either bacteria or actinomycetes. There are also algae, which are found as motile single cells or non-motile filaments.
Soil fauna ranges from microfauna, usually defined as animals less than .004 inches long, through macrofauna to megafauna, which are the largest soil organisms. Microfauna include single-celled protozoa, some smaller nematodes, small flatworms, rotifers and tardigrades. Many microfauna only exist in the water films on the organic matter. The most common macrofauna are the small white segmented enchytraeidae that feed on fungi, bacteria and decaying matter. Soil macrofauna play a valuable role in fragmenting organic waste, thus increasing its surface area. In addition, with the help of symbiotic organisms in their guts, some also break down complex substances such as cellulose, keratin and chitin. Megafauna include the larger earthworms, which also pass both soil and organic matter through their guts. The fragmented organic waste and soil fauna excretions create an environment ideal for the growth of micro-organisms. The continuous cycle of consumption, digestion and excretion by soil fauna alternates with increases in the population of micro-organisms.
Heterotrophic soil micro-organisms, which derive their carbon and energy from organic materials are concerned mainly with the breakdown of organic matter, the carbon cycle and nitrogen fixation. Autotrophic micro-organisms, which obtain carbon from carbon dioxide and energy from the oxidation of simple organic compounds, form nitrites and nitrates and oxidize sulfur and iron compounds. Most micro-organisms produce carbon dioxide, which dissolves in water to form carbonic acid. Mineral elements such as sodium, potassium and magnesium are released to the soil during the decomposition process. The weak carbonic acid dissolves relatively insoluble soil minerals.
The different bacteria outlined above produce different enzymes, which are the protein catalysts responsible for the metabolism of organic waste. The principal enzyme types important in the decomposition of food waste are:
When conditions are desirable for decomposition, such as within the Green Cone, only a small residue of humic substances (consisting of lignin and protein) remains.