Outlook on Anaerobic Digestion Process and Methods to Evaluate Biogas – A

Nowadays the water treatment plants are assembled with anaerobic digesters for biogas production where the sewage sludge is digested and in turn the energy recovered is used for electricity generation and heat production. Ultimately the sludge volume reduces, which is the major aid to treatment plants and additionally the digestate residue can be reused as a soil conditioner to enhance plant growth and health. Moreover the fossil fuels are dipping to the critical point of exhaustion today which leads to investigations all around the world, to find sources for renewable energy production. Biogas is a renewable, alternative fuel, and to enhance the methane production and to make it as a commercial product, led to the development of innovative techniques and research within the field of anaerobic digestion. There are several methods available to determine methane potential and the automated methane potential test system is the latest among all these methods. On the other hand, gas chromatography is a conventional technique used mainly in this field of science for long time and therefore the whole research on anaerobic digestion and biogas production has been relied on this technology. In this study methane potential of different substrates and substrate mixtures of interest were detected using two different measurement methods, i.e. by Automated Methane Potential Test System (AMPTS) and by gas chromatography (GC). Among the investigated substrates citrus peel seemed to be the most difficult one, therefore the optimal inoculums substrate ratio (I/S ratio) was also determined when utilizing citrus peel. Moreover the characterization of the digestate residue was also performed, to be able to detect any inhibitory effects of the reject water on nitrifying bacteria in the water treatment system [1,2]. As the investigations were connected to the water treatment plant, the determination of heavy metals and the ammonium and phosphorus content was also important to carry out.