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Recycling is the process of converting waste materials into new materials and objects. It is an alternative to "conventional" waste disposal that can save material and help lower greenhouse gas emissions. Recycling can prevent the waste of potentially useful materials and reduce the consumption of fresh raw materials, thereby reducing: energy usage, air pollution, and water pollution.
System dynamics (SD) is an approach to understanding the nonlinear behaviour of complex systems over time using stocks, flows, internal feedback loops, table functions and time delays.
Industrial ecology (IE) is the study of material and energy flows through industrial systems. The global industrial economy can be modelled as a network of industrial processes that extract resources from the Earth and transform those resources into commodities which can be bought and sold to meet the needs of humanity. Industrial ecology seeks to quantify the material flows and document the industrial processes that make modern society function. Industrial ecologists are often concerned with the impacts that industrial activities have on the environment, with use of the planet's supply of natural resources, and with problems of waste disposal. Industrial ecology is a young but growing multidisciplinary field of research which combines aspects of engineering, economics, sociology, toxicology and the natural sciences.
Life-cycle assessment is a technique to assess environmental impacts associated with all the stages of the life-cycle of a commercial product, process, or service, e.g., in the case of a manufactured product, from raw material extraction and processing (cradle), through the product's manufacture, distribution and use, to the recycling or final disposal of the materials composing it (grave).
Zero Waste is a set of principles focused on waste prevention that encourages the redesign of resource life cycles so that all products are reused. The goal is for no trash to be sent to landfills, incinerators, or the ocean. Currently, only 9% of plastic is actually recycled. Zero waste system, material will be reused until the optimum level of consumption. The definition adopted by the Zero Waste International Alliance (ZWIA) is:
Zero Waste: The conservation of all resources by means of responsible production, consumption, reuse, and recovery of all products, packaging, and materials, without burning them, and without discharges to land, water, or air that threaten the environment or human health.
The recycling of paper is the process by which waste paper is turned into new paper products. It has a number of important benefits: It saves waste paper from occupying homes of people and producing methane as it breaks down. Because paper fibre contains carbon, recycling keeps the carbon locked up for longer and out of the atmosphere. Around two thirds of all paper products in the US are now recovered and recycled, although it does not all become new paper. After repeated processing the fibres become too short for the production of new paper - this is why virgin fibre will be added to the pulp recipe.
Downcycling, or cascading, is the recycling of waste where the recycled material is of lower quality and functionality than the original material. Often, this is due to the accumulation of tramp elements in secondary metals, which may exclude the latter from high-quality applications. For example, steel scrap from end-of-life vehicles is often contaminated with copper from wires and tin from coating. This contaminated scrap yields a secondary steel that does not meet the specifications for automotive steel and therefore, it is mostly applied in the construction sector.
Electronic waste or e-waste describes discarded electrical or electronic devices. Used electronics which are destined for refurbishment, reuse, resale, salvage recycling through material recovery, or disposal are also considered e-waste. Informal processing of e-waste in developing countries can lead to adverse human health effects and environmental pollution.
Precycling is the practice of reducing waste by attempting to avoid bringing items which will generate waste into home or business. The U.S. Environmental Protection Agency (EPA) also cites that precycling is the preferred method of integrated solid waste management because it cuts waste at its source and therefore trash is eliminated before it is created. According to the EPA, precycling is also characterized as a decision-making process on the behalf of the consumer because it involves making informed judgments regarding a product's waste implications. The implications that are taken into consideration by the consumer include: whether a product is reusable, durable, or repairable; made from renewable or non-renewable resources; over-packaged; and whether or not the container is reusable.
Material flow analysis (MFA), also referred to as substance flow analysis (SFA), is an analytical method to quantify flows and stocks of materials or substances in a well-defined system. MFA is an important tool to study the bio-physical aspects of human activity on different spatial and temporal scales. It is considered a core method of industrial ecology or anthropogenic, urban, social and industrial metabolism. MFA is used to study material, substance, or product flows across different industrial sectors or within ecosystems. MFA can also be applied to a single industrial installation, for example, for tracking nutrient flows through a waste water treatment plant. When combined with an assessment of the costs associated with material flows this business-oriented application of MFA is called material flow cost accounting. MFA is an important tool to study the circular economy and to devise material flow management. Since the 1990s, the number of publications related to material flow analysis has grown steadily. Peer-reviewed journals that publish MFA-related work include the Journal of Industrial Ecology, Ecological Economics, Environmental Science and Technology, and Resources, Conservation, and Recycling.
Material flow accounting (MFA) is the study of material flows on a national or regional scale. It is therefore sometimes also referred to as regional, national or economy-wide material flow analysis.
Urban metabolism is a model to facilitate the description and analysis of the flows of the materials and energy within cities, such as undertaken in a material flow analysis of a city. It provides researchers with a metaphorical framework to study the interactions of natural and human systems in specific regions. From the beginning, researchers have tweaked and altered the parameters of the urban metabolism model. C. Kennedy and fellow researchers have produced a clear definition in the 2007 paper The Changing Metabolism of Cities claiming that urban metabolism is "the sum total of the technical and socio-economic process that occur in cities, resulting in growth, production of energy and elimination of waste." With the growing concern of climate change and atmospheric degradation, the use of the urban metabolism model has become a key element in determining and maintaining levels of sustainability and health in cities around the world. Urban metabolism provides a unified or holistic viewpoint to encompass all of the activities of a city in a single model.
Waste are unwanted or unusable materials. Waste is any substance which is discarded after primary use, or is worthless, defective and of no use. A by-product by contrast is a joint product of relatively minor economic value. A waste product may become a by-product, joint product or resource through an invention that raises a waste product's value above zero.
Economy-wide material flow accounts (EW-MFA) is a framework to compile statistics linking flows of materials from natural resources to a national economy. EW-MFA are descriptive statistics, in physical units such as tonnes per year.
A circular economy is an economic system aimed at eliminating waste and the continual use of resources. Circular systems employ reuse, sharing, repair, refurbishment, remanufacturing and recycling to create a close-loop system, minimising the use of resource inputs and the creation of waste, pollution and carbon emissions. The circular economy aims to keep products, equipment and infrastructure in use for longer, thus improving the productivity of these resources. All 'waste' should become 'food' for another process: either a by-product or recovered resource for another industrial process, or as regenerative resources for nature, e.g. compost. This regenerative approach is in contrast to the traditional linear economy, which has a 'take, make, dispose' model of production.
A nutrient cycle is the movement and exchange of organic and inorganic matter back into the production of matter. Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cyclic. Mineral cycles include the carbon cycle, sulfur cycle, nitrogen cycle, water cycle, phosphorus cycle, oxygen cycle, among others that continually recycle along with other mineral nutrients into productive ecological nutrition.
Social metabolism or socioeconomic metabolism is the set of flows of materials and energy that occur between nature and society, between different societies, and within societies. These human-controlled material and energy flows are a basic feature of all societies but their magnitude and diversity largely depend on specific cultures, or sociometabolic regimes. Social or socioeconomic metabolism is also described as "the self-reproduction and evolution of the biophysical structures of human society. It comprises those biophysical transformation processes, distribution processes, and flows, which are controlled by humans for their purposes. The biophysical structures of society and socioeconomic metabolism together form the biophysical basis of society."
Resource recovery is using wastes as an input material to create valuable products as new outputs. The aim is to reduce the amount of waste generated, thereby reducing the need for landfill space, and optimising the values created from waste. Resource recovery delays the need to use raw materials in the manufacturing process. Materials found in municipal solid waste, construction and demolition waste, commercial waste and industrial wastes can be used to recover resources for the manufacturing of new materials and products. Plastic, paper, aluminium, glass and metal are examples of where value can be found in waste.
Martin Faulstich is a German research scientist. He is a professor at the Clausthal University of Technology, chairman of the German Advisory Council on the Environment and the managing director of the Clausthal Institute of Environmental Technology (CUTEC) in Clausthal-Zellerfeld.
Environmental systems analysis (ESA) is a systematic and systems based approach for describing human actions impacting on the natural environment to support decisions and actions aimed at perceived current or future environmental problems. Impacts of different types of objects are studied that ranges from projects, programs and policies, to organizations, and products. Environmental systems analysis encompasses a family of environmental assessment tools and methods, including life cycle assessment (LCA), material flow analysis (MFA) and substance flow analysis (SFA), and environmental impact assessment (EIA), among others.
References
- ↑ Pauliuk, Stefan; Müller, Daniel B. (2014). "The role of in-use stocks in the social metabolism and in climate change mitigation". Global Environmental Change. 24: 132–42. doi:10.1016/j.gloenvcha.2013.11.006. hdl:11250/2367975.
- 1 2 Müller, Esther; Hilty, Lorenz M.; Widmer, Rolf; Schluep, Mathias; Faulstich, Martin (2014). "Modeling Metal Stocks and Flows: A Review of Dynamic Material Flow Analysis Methods". Environmental Science & Technology. 48 (4): 2102–13. Bibcode:2014EnST...48.2102M. doi:10.1021/es403506a. PMID 24494583.
- ↑ Elshkaki, A (2005). "Dynamic stock modelling: A method for the identification and estimation of future waste streams and emissions based on past production and product stock characteristics". Energy. 30 (8): 1353–63. doi:10.1016/j.energy.2004.02.019.
- ↑ Van Der Voet, Ester; Kleijn, René; Huele, Ruben; Ishikawa, Masanobu; Verkuijlen, Evert (2002). "Predicting future emissions based on characteristics of stocks". Ecological Economics. 41 (2): 223–34. doi:10.1016/S0921-8009(02)00028-9.
- ↑ b. Müller, Daniel (2006). "Stock dynamics for forecasting material flows—Case study for housing in the Netherlands". Ecological Economics. 59: 142–56. doi:10.1016/j.ecolecon.2005.09.025.