Analysis of the recovery of energy and high-added value chemicals from winery wastewater

Abstract

The growing global demand for energy, water, and chemicals, driven by population growth and industrialization, underscores the urgent need for sustainable technologies to address resource scarcity and environmental degradation. This thesis explores two independent innovative approaches for transforming winery wastewater (WWW) to energy and high-value products through, respectively, microbial fuel cells (MFCs) and chain elongation (CE). Two singlechamber MFCs were operated in parallel. The cells were adapted to domestic wastewater as substrate and then operated with synthetic WWW. The maximum power output was 1238.4 mW/m³, 3.3% of Coulombic efficiency, and 0.09% of Normalized energy recovery based on the treated volume. The headspace gas composition showed methane production as a side reaction when WWW was introduced. Stable carbon isotope analysis points to potential characteristics of environments dominated by acetate-dependent methanogenesis. For the CE essays, nine fed-batch bioreactors were operated. Acetic (C2) and/or butyric acid (C4) were added as source of electron acceptors for e- from ethanol oxidation, and after only real WWW was added as substrate. Heating shocks and 2-bromoethanesulfonate were tested to limit methanogenic activities. The best conversion of short- to medium-chain carboxylic acids was in a reactor without controlling methanogens, while fed with WWW and previously fed with only C2, leading to a high concentration of 15.0 g C6/L. Additionally, a model for chain elongation was proposed. By exploring the potential of MFCs and CE, this thesis contributes to advancing in sustainable practices in viticulture, transforming waste into valuable resources.