School of Civil Engineering

An integrated approach for the sustainable closed loop management of agricultural residues

Australia is currently faced with the challenge of sustainably managing its abundant agricultural residue that has significant potential as feedstock for bioenergy production. Anaerobic digestion (AD) is considered a sustainable technology for treatment of agricultural waste matter resulting in energy generation and a partially stabilised effluent called digestate. However regardless of the energy generation benefits, economic and technological barriers still exist for large scale deployment of biogas technology in decentralised and rural regions. Additionally, there is lack of alternative technologies for the treatment of the digestate waste prior to use as fertiliser for soil conditioning and/or for safe disposal. To solve these drawbacks, integration of AD with an energy efficient form of combustion, termed self-sustaining smouldering (SSS) in a biorefinery system is proposed.

This research project aims to understand the limits at which the operational conditions and parameters of both technologies (SS-AD and SSS) could converge, and the analytical characteristics and quality of the stabilised ash. Therefore, the present study for the first time will assess the possibility of optimising key operational parameters for maximizing energy recovery from SS-AD at a threshold condition necessary for optimal operation of SSS post treatment, and investigate the suitability of SSS post-treatment stabilised ash for recycling as fertilizer for soil conditioning and/or safe disposal, and as source of buffer and nutrient for the AD process without introducing an external material such as inorganic chemicals. Finally, the long-term sustainability of the proposed integrated processes will be evaluated in terms of energy generation and consumption, environmental impact and cost effectiveness. The knowledge from this thesis should allow achievement of a sustainable closed-loop in agricultural waste management vis-à-vis waste management, energy generation and nutrient recycling, aiding the achievement of a circular economy that would result to global economic benefits.

9:30am - 10:30am

Tuesday, 29 January 2019


Room 420
General Purpose South (78)