Department Seminar - Michael Kornaros
Residual biomass, in liquid or solid form, is characterized by high organic load which, in combination with other physicochemical characteristics, make its direct environmental disposal impossible. In order to tackle this serious environmental problem, two approaches will be presented, aiming at the integrated exploitation of (a) liquid agroindustrial wastes for the production of biofuels (hydrogen, methane) and added-value products (soil conditioner, liquid fertilizer), and (b) two streams of solid wastes, i.e. used disposable nappies and expired food products, that are currently disposed of to landfills. Regarding the first case, research and development of the anaerobic digestion process of single or multiple substrates (wastes and agricultural residues) at laboratory and pilot-scale, will be presented along with the optimization and modeling of the individual stages of hydrolysis, acidogenesis and methanogenesis as well as the technico-economic evaluation of the integrated process. In the context of full exploitation of organic substrates, from the development of a bio-refinery point of view, the results of microalgal cultivation in the liquid anaerobic digestate of the aforementioned process, will be presented. The microalgal biomass is used to produce lipids, high added-value products and enhance further the energy efficiency of the integrated system. In the second case, the approach for the integrated management of used disposable nappies and expired food products for the production of biofuels, through a two-stage co-digestion system, and the recovery of recyclable materials with potential for further exploitation, will be presented. The proposed solution was developed by the research team of the Laboratory of Biochemical Engineering and Environmental Technology in the framework of the European project WASTE4THINK “Moving Towards Life Cycle Thinking by Integrating Advanced Waste Management Systems”.