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Charcoals were produced from spruce and beech wood under laboratory conditions at different pyrolysis temperatures (300–1300 °C). Characterization of these charcoals was conducted using eight analytical methods. Each method describes specific changes in the temperature range until 1300 °C. Therefore, the combination of these methods provides comprehensive information on different pyrolysis stages. Fourier transform infrared (FTIR) spectroscopy, NMR spectroscopy, and thermogravimetry display changes until 700 °C. A prediction model for pyrolysis temperature until 800 °C is presented based on FTIR spectra with an R 2 of 0.98. He-pycnometry resolves the temperature range between 500 and 890 °C. Small angle X-ray scattering (SAXS) describes precisely the evolution of the porous structure and completes the set of techniques by a description of the physical properties of the charcoal. X-ray diffraction (XRD) reveals the crystallographic change of the lignocellulosic structure toward precursors of graphite. The formation of calcite out of CaO and CO2 becomes evident.

Conventional parameters (loss on ignition, total organic carbon, total nitrogen, C/N-ratio, respiration activity (RA₄), compost status (= 'Rottegrad'), NH₄-N and NO₃-N) are not correlated to humification. At best, they provide information on the biological stability (status of degradation) of composts. Humic substances which are a source of stable organic matter and nutrients are discussed as a parameter describing compost quality. Thus, in the present research project a photometric method evaluating humic acids was used to characterize the quality of 211 Austrian and foreign composts made from source-separated collected biowaste or sewage sludge. Furthermore, parameters influencing the formation of humic acids during the rotting process were investigated by implementing rotting experiments in the laboratory as well as in composting plants. The analysed composts showed humic acid contents between 2.5 and 47 %, calculated on a organic dry matter (oDM) basis. In addition to the duration of treatment the main influence on humification was the feedstock used. Stabilized sewage sludge, biowaste after intensive anaerobic pre-treatment or biowaste with low reactivity (RA₄) or uniform composition (e.g. mainly grass) showed a low formation of humic acids. For optimum humification the feedstock needed to contain components that are well balanced from scarcely to easily degradable compounds. Processing also influenced humification. Open windrow systems and reactor systems allow the same quality to be produced when operated well, but optimizing mineralization (e.g. very intensive aeration) showed negative effects. The positive condition required for humification is an unhurried (not too intense) degradation with long-lasting biological activity in which microbes have enough time to use the metabolic products of degradation for humification.