Sustainability analysis of implementing sludge reduction in overall sludge management process: Where do we stand?. (October 2022)

• Record Type: Journal Article
• Authors: Liu, Xiaoming; Huang, Hao; Iqbal, Asad; Chen, Jing; Zan, Feixiang; Jiang, Chengchun; Chen, Guanghao
• Is Part Of: Waste management. Volume 152(2022)
• Page Start: 80
• Page End: 93
• Publication Date: 2022-10
• Subjects: Waste management -- Sludge reduction -- Life cycle analysis -- Sludge management -- Economic analysis; AO Anoxic-aerobic -- AD Anaerobic digestion -- BOD Biological oxygen demand -- CA China 1A -- CB China 1B -- COD Chemical oxygen demand -- CJ Class JB-A level of Beijing effluent standard in Beijing -- DS Dewatered sludge -- DOC Degradable organic carbon -- EC Energy consumption and recovery -- FE Freshwater eutrophication -- FU Functional unit -- GHG Greenhouse gas -- IN Incineration -- LA Land application -- LCA Life cycle assessment -- LCC Life cycle cost -- LF Landfill -- ME Marine eutrophication -- OF Ozone formation -- OSA Oxic-settling-anaerobic -- PAM Polyacrylamide -- SSR Side-stream reactor -- SR Sensitivity ratio -- TA Terrestrial acidification; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2022.08.013
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: Whether to use sludge reduction was environmentally and economically assessed. Nine scenarios of sludge management involving different technologies were evaluated. COD flows from wastewater influent to final sludge destination were revealed. Direct incineration without sludge reduction has the least environmental impact. The economic impacts highly depend on the region-specific situations. Abstract: Sustainable sludge management has significance due to the great potential of recovering energy and resources, potentially achieving carbon neutrality and energy positivity in the process. However, whether the sludge reduction strategy really benefits the aim of a sustainable sludge management process requires a holistic analysis. In this study, nine scenarios involving different sludge management strategies with or without sludge reduction methods were environmentally and economically assessed to clarify the necessity of adopting a sludge reduction or not. Results reveal that direct sludge incineration without prior in-plant sludge reduction generates the least environmental impacts (less than 25–120 %), but it increases operation costs by 103–110 % compared to landfilling with prior in-plant sludge reduction. Chemical Oxygen Demand flows indicate that direct sludge incineration is superior in converting organic matter into energy compared to employing sludge reduction followed by landfilling or land application. This converted energy offsets environmental impacts from electricity consumption, but these electricity benefits are insignificant in the overall cost. Case studies suggest that direct sludge incineration could facilitate potential nutrient and energy recovery, especially for metropolis. While sludge reduction strategies are more suited for developing regions relying on landfills or land application, to lower the economic burdens. The findings of this study tend to shed light on the decision-making of adopting sludge reduction strategies and sustainable sludge management.