Subject and Keywords:
For imaging of the biogas process fast and long-term stable measurement methods misses for certain parts of the process. Thus, it is necessary to know the development of organic acids. These metabolites, which are generated during the bacterial degradation, are important indicators. The process is generally very confusing, not only in terms of the number of occurring bacteria and chemical compounds, but also their variabilities. For the knowledge of such changes a direct, low-wear and permanent monitoring of organic acids would be extremely useful. Upon the occurrence of a change like hyperacidity we could react quickly. There are already some proven methods. However, these methods have several disadvantages: the information gathering is logistically difficult by long journeys, by process conditions information’s are delayed and distorted, quickly worn sensors, etc. Therefore, a innovative development is presented here, which avoids all the disadvantages listed. The sensor unit has been developed in cooperation with KSI Meinberg, Logic Way Schwerin, IBZ Hohen Luckow, University of Rostock and a polish colleague. According to Raoult law a characteristic is used in principle, which is typical of some liquid and gaseous media that are touching. This means volatile substances, which for example, are also in the fermenter broth, among others organic acids, are also detectable in the gaseous phase. If in the gas phase such acids can be detected, conclusions about the acid content in the substrate broth are possible. In different experiments evaluable matches between the developments of organic acids on the one hand in the liquid phase (broth) and on the other hand, in the gaseous phase were found. These results are based on an acid sensor unit with which distant standing biogas plants can be controlled remotely. A project regarding this topic is supported by research programme ZIM. Project executing organization is AiF (Arbeitsgemeinschaft industrieller Forschungsvereinigungen “Otto von Guericke” e.V.).