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A brief explanation of aerobic compost formationCompost formation is the oldest recycling process in the world for organic waste and was already used by the Romans in ancient times.
In the course of aerobic composting, organisms in the soil decompose biological waste with oxygen. In the process, primarily carbon dioxide, water, heat and a decomposition product resembling humus, which is used as fertilizer, are created. The decomposition can be attributed to microorganisms in the soil (e.g. funghi, bacteria) and soil animals (e.g. earthworms). | |  | | | Characteristic rotting processThe rotting process with its characteristic temperature profile is divided into three phases:
- 1st phase: Intensive or preliminary composting
Splitting up and mineralization of easily degradable organic substances (e.g. sugar, starch, hemicellulose).
Intensive bacterial activity with high metabolic rate.
First above all mesophyllic bacteria degrade the organic substances, causing the temperature in the compost pile to rise; then thermophyllic bacteria take over the work.
Temperature up to over 65° C. - 2nd phase: Main composting
Decomposition of complex organic substances (e.g. lignine, cellulose). Mixed population with actinomycetane, mould and thrus funghi with low metabolic activity.
Temperature 50 to 25° C. - 3rd phase: Final composting
Production of humic acid and clay-humus complexes.
Mixed population with actinomycetane, invertebrates.
Temperature drops up to below 20°C.
Fig. 1 : Characteristic rotting process | | | | | Only the intensive composting phase can be controlledContrary to that of funghi and invertebrates, the metabolic activity of bacteria is easily influenced. Since bacteria primarily are active during the intensive composting phase, this is the only phase in industrial compost formation that can be controlled by means of the following parameters:
- Water content
Bacteria absorb nutrients only from aqueous phase. If the compost pile is too dry, the bacterial metabolic activity and the rate of decomposition decline. If it is too wet, the oxygen is increasingly displaced from the pores of the rotting material , the bacteria work anaerobically. - Oxygen concentration
If there is not sufficient oxygen available for the aerobic decomposition of the rotting material, the bacteria population switches over to an anaerobic decomposition program. Then such smelly and unhealthy sludge gas as mercaptane, hydrogen sulphide and ammonia as well as methane are generated. If the compost is ventilated excessively, it dries out too much. - Temperature
During the composting process, the bacteria population works optimally only at a certain temperature. A constant high temperature over a certain period of time kills morbific germs, which are unhealthy for people, animals and plants, as well as undesired wild seed and ensures appropriate hygienization of the compost.
For controlling the temperature and oxygen concentration in a compost pile, the temperature measuring system MF420-5T-100 and the oxygen measuring system MF420-O-M are available. |
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