Valorization of Bio-Waste by Electrochemical Treatment and Beyond

The management and disposal of biomass wastes remains a global challenge due to environmental concerns, public health risks, and substantial operating costs. This dissertation presents innovative approaches addressing critical challenges in waste management while promoting sustainability. The first section explored the treatment and disposal of waste activated sludge (WAS). A novel electrochemical method in alkaline media was developed, achieving a 25% reduction in disposal costs compared to conventional methods. Additionally, a 90% reduction in energy consumption was demonstrated. The generated biosolid showed promise for safe landfilling and agricultural applications (Class A biosolid). The second section focused on electrochemical conversion of biowaste into value-added short chain fatty acids (SCFAs) and hydrogen. Electrochemical conversion (E-WAS) was performed using non-precious metal electrodes (copper, nickel, and stainless steel) in an alkaline environment at low temperature and applied potential. Copper, with Cu(II)/Cu(III) exhibited superior SCFA production capability and WAS disinfection. Additionally, ammonia was produced as a by-product of E-WAS oxidation, with nickel electrodes yielding the highest ammonia concentration of 250 mg L-1. The last part of the dissertation delved into sustainable energy storage, presenting the development of hierarchically porous carbon materials derived from biomass waste sources. These materials, with a high surface area of 1197.91 m2 g-1, were employed in supercapacitors with sodium acetate electrolyte. The supercapacitor exhibited exceptional cycle stability (98.4% retention after 20,000 cycles) and a maximum energy density of 15.9 Wh kg-1 highlighting its potential as an environmentally friendly energy storage solution.

Embargo status: Restricted until 01/2030. To request the author grant access, click on the PDF link to the left.