Sustainable Future Waste Management and Recycling Strategies

Dear Colleagues,

Waste management and recycling are strategically important parts of a sustainable society. They have links both to resource efficiency and to ecological and environmental factors such as air and water pollution, and not least to increasing CO₂ levels in the atmosphere and global warming. The collection of recycling and waste fractions should also take place as efficiently as possible in order to minimize emissions of fossil carbon dioxide from transport. This can, e.g., be obtained through various forms of “collection on demand” solutions. Unnecessary transports to customers who may have nearly empty waste or recycling bins are avoided.

When it comes to treatment methods for residual waste, biological solutions are often preferred because these harmonize with natural ecological processes. This can apply to both composting and biological fermentation for the production of biogas. Biogas is a very useful and flexible raw material that can be used both in the chemical industry and for power and heat production. At the same time, a bioresidue remains that can have great value as a soil improvement in both forestry and agriculture, as well as in horticulture.

The technology for the landfilling of waste has developed greatly in recent years, and a well-controlled landfill can today be seen as a biological treatment method, where biogas can be extracted and the leachate can be used as a nutrient in, for example, energy forest cultivations within the defined landfill area. At the same time, plastics and other fossil-derived material are stored for a long time in the fermentation residues in the landfill and may constitute a material resource in the future, when there may be a shortage of raw materials. From a carbon dioxide point of view, the landfill can be compared to nature’s peatlands or lake and sea sediments, where excess organic carbon can be stored as long-lived organic materials. A well-controlled landfill can thus counteract elevated CO₂ levels in the atmosphere. Provided that the formed biogas is collected efficiently and used as, for example, a renewable fuel, the well-controlled landfill can thus also constitute “a measure against global change”. New scientific knowledge about methane gas oxidation potential is also important to minimize the risk for diffuse leakage of methane from landfills to the atmosphere.

From an ecological point of view, direct incineration of MSW and light industrial waste should only take place for waste that is so unpolluted that the ash can be used as a fertilizer or soil improver, e.g., non-treated wood, some coarse garden waste, and so on. In this way, an eco-cycling of nutrients is created, and conditions for a circular economy are stimulated. Incineration of mixed municipal solid waste with contaminating pollutants such as heavy metals means that the nutrients in the ashes become contaminated and the ashes will be regarded as hazardous waste, and the opportunities for reuse of the nutrients are lost. Incineration of fossil-derived material, such as plastic, synthetic rubber or synthetic textiles, causes fossil CO₂ emissions into the atmosphere in the same way as with the combustion of coal and oil. In addition to this, heavy metals from stabilizers or used dye in the plastics will be bound to submicrone particles in the stack gasses during combustion and hard to separate with existing stack gas filters. These small particles are also respirable and can easily go down into the pulmonary system of humans.

In general, the manufacturing industry should strive to manufacture products that are easy to recycle. This is to be able to extend the life of the materials and enable efficient reuse or recycling, which is important from a life cycle analysis point of view. In a circular economy, recycling of materials and nutrients has a very high priority.

The issue focuses on research on future smart waste management techniques. Thus, the scope is to present and evaluate new results concerning environmental, technical, and social aspects of different options for a low waste and eco-cycling society. This includes issues from minimizing residual waste through material recycling at source, and smart collection systems to minimizing transportation and fossil CO₂ emissions. It also includes developing and refining techniques for extraction of biogas and nutrients from residual solid wastes using different biological treatment options, including controlled bioreactor cell landfills as well as reactor fermentation. Some of the highlights include the effects on climate change and CO₂ balances, such as methane gas oxidation in landfill surface layers. The issue also focuses on new strategies for the collection of waste and recycled products to minimize the total transportation work and, thus, exhaust emissions.

Prof. Dr. Torleif Bramryd
Dr. Michael Johansson
Guest Editors

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• material recycling
• biological treatment
• circular economy
• sustainable landfilling
• biogas
• landfill gas
• carbon sequestration
• methane oxidation
• leachate treatment
• leachate irrigation
• on demand collection
• landfill gas oxidation
• transfer station