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Life cycle assessment of a sewage sludge and woody biomass co-gasification system

Lookup NU author(s): Srikkanth Ramachandran, Professor Ulrich Stimming



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


© 2017 Elsevier Ltd. Replacing a part of energy derived from fossil fuels with bioenergy derived from solid waste streams may be a promising method to tackle the dual crisis of increasing waste pile-up and global climate change. In this study we propose a decentralised sewage sludge and woody biomass co-gasification system for Singapore. We evaluate the greenhouse gas emission of the proposed system and compare it to the existing system through life cycle assessment. The proposed system is expected to provide a net annual emission reduction of 137.0-164.1 kilotonnes of CO2eq. Increase in electricity recovery, carbon sequestration in the biochar produced and the avoidance of the use of supplementary fuel for sewage sludge incineration are the major contributors for the emission reduction. The proposed system is able to increase the net electricity production from sewage sludge and woody biomass by 3-24%. This could lead to an annual increase in electricity recovery of 12.1-74.8 GWh. It is estimated that the proposed system can produce 34 kilotonnes of biochar annually. It is found that decentralisation helps to reduce the annual tonne-km driven by 4.23 million tonne-km which could decrease the number of on-road vehicles required for waste handling.

Publication metadata

Author(s): Ramachandran S, Yao Z, You S, Massier T, Stimming U, Wang C-H

Publication type: Article

Publication status: Published

Journal: Energy

Year: 2017

Volume: 137

Pages: 369-376

Print publication date: 15/10/2017

Online publication date: 25/04/2017

Acceptance date: 24/04/2017

Date deposited: 17/11/2017

ISSN (print): 0360-5442

Publisher: Elsevier Ltd


DOI: 10.1016/


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