Carbon Neutrality

Deadline for manuscript submissions: 31 March 2024.

Topic Editors (5)

Andrea G.  Capodaglio
Prof. Andrea G. Capodaglio 
Fellow IWA, BCEE, University of Pavia, Pavia, Italy
Interests: Sustainable Development; Energy and Materials Recovery; Innovative Water and Wastewater Treatment; Groundwater Contamination; Bioelectrochemical Systems
Chengcheng  Tian
Prof. Chengcheng Tian 
School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China
Interests: CO2 Capture and Utilization; Pollutant Absorption; Environmental Catalysis; Energy Materials; Energy Conversion; Energy Efficiency; Resource Efficiency; Sustainable Resources Management
Lidong  Wang
Prof. Lidong Wang 
MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, China
Interests: Flue Gas; CO2 Capture; Desulfurization; Catalysis; Absorption
Ming  Xu
Prof. Ming Xu 
School for Environment & Sustainability, University of Michigan, Ann Arbor, MI, USA
Interests: Sustainable Systems; Structural Decomposition Analysis; Carbon Emissions; Material Flow Analysis
Xiuping  Zhu
Prof. Xiuping Zhu 
Department of Environmental Science and Engineering, Fudan University, Shanghai, China
Interests: Water Quality and Treatment; Renewable Energy; Hydrogen and Power Generation; CO2 Utilization

Topic Collection Information

Topic Introduction

Carbon neutrality, as a state of net-zero CO2 emissions, which can be achieved by counterbalanced all worldwide greenhouse gas emissions by carbon sequestration. Another way to reduce emissions and to pursue carbon neutrality is to offset emissions made in transportation, energy production, agriculture, and industry by reducing them through science-based measures such afforestation and energy saving and reduction emission. This can be done through development of renewable energy, energy efficiency or other clean, low-carbon technologies ( In the 75th session of the UN General Assembly President Xi Jinping proposed that China will increase its National Determined Contribution and adopt more powerful policies and measures. We strive to peak CO2 emissions before 2030 and achieve carbon neutrality before 2060 ( ( Till the end of December 2021, net zero targets has been set by 136 countries, 115 regions, 235 cities, and 682 companies, which have covered 88% of global greenhouse get emissions, 90% of global GDP and 85% of the world's population (


  • Carbon Neutral Energy
  • Carbon Neutral Technology
  • Net Zero Carbon
  • Carbon Sink
  • Carbon Offsetting
  • Carbon Footprint
  • Carbon Reduction
  • Carbon Neutral Policy

Published Papers (2 papers)


29 January 2023

Carbon Neutrality and Life Cycle Thinking

Climate change is one of the most critical sustainability challenges facing the humanity. International communities have joined forces to mitigate climate change impact and aim to achieve carbon neutrality in the coming decades. To achieve this ambitious goal, life cycle thinking can play critical roles. Specifically, life cycle thinking helps evaluate the true climate impacts to avoid shifting emissions across processes in a product life cycle. It can also help inform consumers with carbon footprint information to make climate-conscious choices. Finally, it can help identify key processes dominating the carbon footprint of a product so that future improvement can set priorities. High quality data is required for accurate and timely carbon footprint accounting and critical challenges exist to obtain and share such data.

Ruoxi  Xiong
Ming  Xu*
Clean Energy and Sustainability-logo


13 March 2023

Reduced Climate Impacts of Dairy Sludge Management by Introducing Hydrothermal Carbonization

Dairies which produce cheese and milk products can, however, produce large volumes of wastewater that require treatment, usually via activated sludge treatment. Disposal of the resulting activated sludge to land is viewed favorably as the sludge is rich in phosphorus (P) and nitrogen (N) and enables nutrient recycling. Nonetheless, sludge management can significantly influence the greenhouse gas (GHG) emissions to the atmosphere. This manuscript has modelled the GHG emissions arising from two sludge management strategies currently adopted by Danish dairies whereby: (i) sludge is stored and later applied to fields; or (ii) sludge is treated by anaerobic digestion (AD), stored, and the digestate will later be applied to fields. This is compared to (iii) an alternative sludge management strategy with treatment by Hydrothermal Carbonization (HTC). HTC is a technologically simple sludge treatment that could lower the cost for dewatering dairy sludge, forming a biochar-like material known as hydrochar. The produced hydrochar can be applied to the land for the purpose of carbon sequestration, P and N recycling. Our calculations indicate that GHG balances of HTC sludge management can result in a net carbon sequestration of 63 kg CO2eq per ton sludge, as opposed to net emissions of 420 and 156 kg CO2eq per ton sludge for strategies (i) and (ii), therefore offering significant reductions GHG emissions for the dairy sector.

Aidan MarkSmith*
Sven GjeddeSommer
Arezoo Taghizadeh-Toosi
Clean Energy and Sustainability-logo