Tailored waste-derived biochar for energy recovery and environmental applications

Abstract

Utilizing renewable biomass wastes such as lignocellulosic biomass and sludge waste as energy sources is one of the readily available solutions to meet the global energy demand. As a negative emission technology highlighted by the IPCC, biochar is regarded as a sustainable solution for water pollution control and an integrated strategy for simultaneous achievement of at least 11 of 17 Sustainable Development Goals (SDGs). By selecting suitable feedstocks and customizing the science-based production methods, biochar can be tailored with distinct physicochemical properties for different emerging applications for wastewater treatment. To identify the possibility of valorizing local biomass waste for energy recovery and environmental applications. This thesis investigated the co-impact of pyrolysis conditions and activation methods on physicochemical properties of wood waste-derived biochar to minimize the application of harsh conditions. The energy potential of food waste digestate-derived hydrochar was also revealed by enhancing the combustion behaviors and carbon utilization efficiency. The role of inherent Ca in feedstocks in hydrothermal carbonization by recirculating process water was studied, the role of pressure in CO2-assisted pressurized hydrothermal carbonization on energy performance was also investigated. Given the increasing treatment demand of biomass waste in Hong Kong (e.g., Y•park for yard waste and O•park for food waste) and the establishment of T•park for sludge incineration, valorizing renewable biomass waste into high-value-added solid fuel via thermochemical treatment for energy application is regarded as a bioeconomic revolution to close the resource loop and foster the circular economy and sustainable development in Hong Kong.