4. International Hydrogen Technologies Congress-IHTEC 2019, 20 - 23 June 2019, no.309
Hydrogen is one of the significant promising green energy sources due to its end products as water and heat. In this study, energy conversion and sustainability of the bio-hydrogen and bio-methane production processes from biological sludge is investigated. Therefore, primary and waste sludge are used as substrate in dark fermentation and methanogenic fermentation. Theoretically, it is possible to produce 2 or 4 mol of hydrogen per mol glucose according to butyric acid and acetic acid pathways. However, COD removal and sludge stabilization cannot be achieved with only dark fermentation. Thus, two-stage of methanogenic fermentation supported after dark fermentation process can provide sludge stabilization and theoretically it has more energy potential per unit substrate. Biological hydrogen potential and methane potentials are determined with Clostridium sp. dominated mixed culture and granular sludge respectively. In that purpose, hydrogen and methane production of primary and waste sludge with two stage fermentation and direct methanogenic fermentation processes are compared due to energy feasibility, carbon footprint and treatment efficiencies.
Keywords: Bio-hydrogen, dark fermentation, sludge stabilization, anaerobic treatment