Composting is the biological process of the nutrient cycle during which organic material that is easily recyclable is broken down by bacteria and fungi under the influence of atmospheric oxygen. In the process, other than carbon dioxide water-soluble minerals such as nitrates, ammonium salts, phosphates, and potassium/magnesium compounds that act as a fertilizer are also released. Nowadays, composting is no longer something which only takes place in people's gardens, but is mainly carried out on a large scale by local municipalities. In Germany, more than 1000 composting plants exist for this purpose.
According to data from the German Federal Statistics Office, in 2011 around 14 million metric tons of biogenic waste was composted or fermented in biogas plants and subsequently re-used on soil in Germany. The German Biowaste Ordinance specifies that the stipulated temperatures for all batches of a composting must be documented. Proof is necessary because dangerous microorganisms are reliably eliminated as a result of the temperature in the material. This data must always be available to the "Bundesgütegemeinschaft Kompost" (Federal Compost Association). The temperature curve must be recorded during hygienic treatment using constant and non-invasive direct temperature measurement in the material being treated. In addition, the temperature must be recorded automatically. Often, this temperature check is carried out manually by the operators of composting plants. The costs for personnel are correspondingly high.
During composting, a temperature of more than 55 °C must act upon the entire mixture for, if possible, a consecutive period of 2 weeks, or 65 °C over 1 week. The treatment temperature must be measured and documented in regular intervals – at least once per work day. Devices used for temperature measurement must be calibrated regularly – at least once a year – and the calibration must be documented. Only if documentation of the indirect process control is verifiable at any time can the manufactured composts be deemed hygienically harmless. Often, this temperature check is carried out manually by the operators of composting plants. The costs for personnel are correspondingly high. Disposal provider "GfA Lüneburg - gkAöR" has chosen the JUMO mTRON T automation system and JUMO Wtrans B wireless temperature probes. As a result, the process is monitored completely automatically and documented in a tamper-proof manner.