Compost definitions

Although a united compost quality system of the European Union does not exist, the European Compost Network (ECN), as an initiative of the ORBIT Association developed a Quality Assurance System providing the necessary background information and documentation to build up a European Quality Assurance System (ECN-QAS). Product definitions and characterizations of this system are shown in Table 12.7. 

Boelens, J. De Wilde, B. De Baere, L. Comparative study on biowaste definition effects on biowaste collection, compost process and compost quality. Compost. Sci. Util. 1996, 4, 60-72. 

These definitions were essentially the same as those put forward by Berzelius. Mulder considered, however, that, besides humus substances, products from the decomposition of organic residues, such as leucine, butyric acid, valeric acid, and formic and ethanoic acids, could exist in soil. These observations are of interest because of the information that has emerged in the past half-century about growth inhibitors and stimulators from low-molecular-weight extracts from SOM and composts. 

This report uses the American Society for Testing and Materials (ASTM) definitions of biodegradable and compostable plastics. 

For all practical purposes of applying a definition, material manufactured to be biodegradable must relate to a specific disposal pathway such as composting, sewage treatment, denitrification, and anaerobic sludge treatment. 

As a result, specified periods of time, specific disposal pathways, and standard test methodologies were incorporated into definitions. Standardisation organisations such as CEN, ISO, and ASTM were consequently encouraged to rapidly develop standard biodegradation tests so these could be determined. Society further demanded undebatable criteria for the evaluation of the suitability of polymeric materials for disposal in specific waste streams such as composting or anaerobic digestion. Biodegradability is usually just one of the essential criteria, besides ecotoxicity, effects on waste treatment processes, etc. 

For the composting environment, specification standards with definite pass / fail criteria requirements are available as ASTM, ISO, and EN standards. All the standards are harmonized and have very minor differences but the basic principles and requirements are the same. EN 13432 and ISO 18606 are specification standards for packaging. The specification standards are as follows ... 

Sustainability has many definitions. One way to think of it is meeting the needs of the present without compromising the ability of future generations to meet their needs (defined by the World Commission on Environment and Development held by the United Nations in 1983). The concept of sustainability is that we should synchronize our consumption of natural resources with the Earth s production - in other words, using up natural resources at the same rate at which they are produced. Compared to traditional polymers typically made from petroleum and other fossil resources such as natural gas, sustainable polymers are fuUy or partially biobased and/or biodegradable or compostable. They are bioplastics made from renewable resources (biomass) and can be broken down faster than traditional plastics. Sustainable polymers could also protect our Earth by offering a reduced carbon footprint, a reduced use of fossil resources, and improved end-of-life options. 

The state-of-the-art in the field of lightweight compostable packaging has been reviewed (5). The review starts with an overview of compostabdity, biodegradabihty and presents some definitions. A brief summary of the current use of synthetic commodity polymers used in packaging is followed by an analysis of commercially available, renewable polymers. An overview of the technology of production has been presented, as well as existing and emerging producers (5). 

Another point of confusion has been the reasonable time part of the definition. As is also true for photodegradation, the time required for biodegradation is a function of exposure conditions (as well as a function of the extent of degradation defined as the end point). Time to reach the defined end point after disposal can be markedly different if the object degrades in sewage sludge, in a compost pile, or in a landfill, even under the same climatic conditions. To this variation, then, must be added differences in ambient temperatures, rainfall, etc. 

Definitions. Standardization of definitions, test methods, and performance criteria are required for degradable, biodegradable, and compostable plastics (as for other plastics), to allow product stewardship, to enable regulatory programs, and to support consumer confidence. In the United States these responsibilities lie with the American Society for Testing and Materials (ASTM). 

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