Sustainable Sludge Management in China: Quantifying GHG Emissions and Exploring Its Reduction Strategies

• Published in: Processes 2024-07, Vol.12 (7), p.1481
• Main Authors: Hu, Dongming, Jiang, Peng, Chen, Yipei, Gao, Fuyan, Liu, Shuai
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Anaerobic treatment; Carbon dioxide; China; Cities; Climate change; Combustion; Costs; Emission analysis; Emissions; Energy consumption; Environmental factors; Evaluation; Feasibility studies; Gasification; Geographical variations; Greenhouse gases; Hydrothermal treatment; Incineration; Industrial efficiency; Land application; Landfill; Landfills; Life cycle assessment; Municipal landfills; Municipalities; Natural resources; Pathogens; Principal components analysis; Pyrolysis; Regional development; Regions; Sludge; Sludge digestion; Sludge drying; Sustainable development; Technology application; Water treatment; Wet oxidation
• ISSN: 2227-9717; 2227-9717
• DOI: 10.3390/pr12071481

This study aims to evaluate the emissions of greenhouse gases (GHGs) stemming from the sludge treatment sector in China and to investigate the feasibility of novel technologies in curtailing these emissions, with the aim of fostering sustainable sludge management methodologies. Employing a life-cycle assessment (LCA) methodology, the research computed the comprehensive GHG emissions resulting from sludge treatment, taking into consideration diverse elements such as treatment techniques (e.g., landfills, incineration, and land application) and the geographical variations among China’s 660 municipalities. Findings indicate that the total amount of GHG emissions from sludge treatment amounted to 18.54 Mt CO2-eq in 2017, with incineration registering the highest emissions (10,011.53 kg CO2-eq/t dry sludge (DS)), followed by landfills (717.51 kg CO2-eq/t DS) and land application (276.41 kg CO2-eq/t DS). The geographical dispersion of emissions characteristics reveal notable regional disparities, with the top 1% of cities responsible for 34.2% of the overall emissions. The concentration of emissions in the top 1 percent of cities underscores the necessity for tailored mitigation measures that consider localized sustainable development challenges. Principal component analysis (PCA) demonstrates that economic determinants and treatment scales exert substantial influence on emissions, underscoring the imperative of aligning Sustainable Development Goals (SDGs) with economic advancement. To curtail the carbon footprint associated with sludge treatment and enhance sustainability, the study evaluated the emission mitigation potential and expenses of diverse technologies, encompassing thermal conversion, anaerobic digestion, hydrothermal treatment, and wet oxidation. These technologies have the capacity to slash GHG emissions by 0.09–0.46 t CO2-eq/t DS in comparison to traditional approaches, while concurrently advancing resource recuperation and principles of circular economy. For instance, gasification could diminish GHG emissions by 0.33–0.46 t CO2-eq/t DS, whereas anaerobic digestion could yield reductions of 0.09–0.30 t CO2-eq/t DS. The implementation of these innovative technologies across 660 Chinese municipalities could potentially curtail total GHG emissions from sludge treatment by 15–40%. Nevertheless, further enhancements are imperative to refine their environmental and economic efficiency and guarantee enduring sustainability. By deploying these technologi