Helix of sustainability

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The helix of sustainability - the Carbon cycle ideal for manufacture and use Helix of sustainability.png
The helix of sustainability - the Carbon cycle ideal for manufacture and use
The international recycling symbol - not nature identical. Recycle001.svg
The international recycling symbol - not nature identical.

The helix of sustainability is a concept coined to help manufacturing industry move to more sustainable practices by mapping its models of raw material use and reuse onto those of nature. The environmental benefits of the use crop origin sustainable materials have been assumed to be self-evident, but as the debate on food vs fuel shows, the whole product life cycle must be examined in the light of social and environmental effects in addition to technical suitability and profitability.

The helix of sustainability [1] [2] [3] is a concept created as a representation of the total systems approach to gain full advantage from manufacturing with sustainable materials, particularly biopolymers and biocomposites. In 2004 the concept was presented by Professor John Wood, then Chair of the Materials Foresight Panel at a DTI event hosted by the then Secretary of State for Industry (Jacqui Smith). [4] In the same year it was also used in the European Science Foundation exploratory workshop on environmentally friendly composites. [5]

The advantages of working with crop origin raw materials are readily observed if the social and environmental impacts are considered as well as monetary cost (the Triple bottom line), and the helix of sustainability helps to demonstrate this. For the full potential of biopolymers to be realised it is essential that attention is paid to every aspect of the manufacturing process from design (how to cope with the incertainties in properties associated with crop origin materials?), manufacture (can existing technologies be used?), through to end-of-life (can the redundant article be fed back into the materials cycle?). The entire supply chain must be considered because decisions taken at the design stage have significant effects right through the life of an article. Low cost assembly techniques (e.g. snap-fits) may make dismantling or repair uneconomical. However, if say, an easy-to-dismantle car is built, will there be any effect on the ability of the vehicle to absorb energy in a crash? At an even more fundamental level, what will be the social and environmental of the change in crop growing patterns. This low environmental impact approach to manufacturing is seen as an extension of waste reduction techniques such as lean manufacturing.

Conventional cycles of use and reuse are circular. Consider the mechanical recovery of conventional polymers. A complex infrastructure is needed to recover the material at the end of an article's useful life. At the end of an article's life - say a PET carbonated drink bottle, the article must be separated from the waste stream, either by the consumer who throws it away, or by manual labour at the rubbish dump. It must then be transported to some facility to be reprocessed (using more labour and energy) back into a raw material. The heat and shear forces associated with the process of remanufacture tends to produce material with slightly degraded properties compared to the original material.

For sustainable material articles there is not such a great requirement for a dedicated recovery infrastructure. If a litter lout throws a crop origin biodegradable article on the ground, it will ultimately biodegrade into humus, water, and non-fossil CO2. If the article is placed into a compostable waste stream, the humus can then be used as fertiliser for the next generation of crops, there is also no requirement to sort biopolymer articles as there is with fossil polymer recycling. Note difference between landfill and compost - the limited biological activity in landfill is slow, and mostly anaerobic resulting in the production of methane, whereas composting is a rapid aerobic process resulting in humus, water and non-fossil CO2. The energy bill for breaking down biodegradables into the fundamental building block molecules, and then reassembling them into usable raw materials is large, but is uses direct solar energy rather than metered electricity. There is also no loss of properties with successive journeys through the cycle.

See also

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Biopolymer Polymer produced by a living organism

Biopolymers are natural polymers produced by the cells of living organisms. Biopolymers consist of monomeric units that are covalently bonded to form larger molecules. There are three main classes of biopolymers, classified according to the monomers used and the structure of the biopolymer formed: polynucleotides, polypeptides, and polysaccharides. Polynucleotides, such as RNA and DNA, are long polymers composed of 13 or more nucleotide monomers. Polypeptides and proteins, are polymers of amino acids and some major examples include collagen, actin, and fibrin. Polysaccharides are linear or branched polymeric carbohydrates and examples include starch, cellulose and alginate. Other examples of biopolymers include natural rubbers, suberin and lignin, cutin and cutan and melanin.

Compost organic matter that has been decomposed

Compost is organic matter that has been broken down into simpler organic or inorganic matter in a process called composting. This process recycles various organic materials otherwise regarded as waste products and produces a soil conditioner.

Biodegradation Decomposition by living organisms

Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi.

Renewable resource

A renewable resource is a natural resource which will replenish to replace the portion depleted by usage and consumption, either through natural reproduction or other recurring processes in a finite amount of time in a human time scale. Renewable resources are a part of Earth's natural environment and the largest components of its ecosphere. A positive life cycle assessment is a key indicator of a resource's sustainability.

Waste hierarchy

Waste hierarchy is a tool used in the evaluation of processes that protect the environment alongside resource and energy consumption from most favourable to least favourable actions. The hierarchy establishes preferred program priorities based on sustainability. To be sustainable, waste management cannot be solved only with technical end-of-pipe solutions and an integrated approach is necessary.

Bioenergy

Bioenergy is renewable energy made available from materials derived from biological sources. Biomass is any organic material which has absorbed sunlight and stored it in the form of chemical energy. As a fuel it may include wood, wood waste, straw, and other crop residues, manure, sugarcane, and many other by-products from a variety of agricultural processes. By 2010, there was 35 GW (47,000,000 hp) of globally installed bioenergy capacity for electricity generation, of which 7 GW (9,400,000 hp) was in the United States.

Polyhydroxyalkanoates

Polyhydroxyalkanoates or PHAs are polyesters produced in nature by numerous microorganisms, including through bacterial fermentation of sugars or lipids. When produced by bacteria they serve as both a source of energy and as a carbon store. More than 150 different monomers can be combined within this family to give materials with extremely different properties. These plastics are biodegradable and are used in the production of bioplastics.

Bioplastic

Bioplastics are plastic materials produced from renewable biomass sources, such as vegetable fats and oils, corn starch, straw, woodchips, sawdust, recycled food waste, etc. Bioplastic can be made from agricultural by-products and also from used plastics by using microorganisms. Bioplastics are usually derived from sugar derivatives, including starch, cellulose, and lactic acid. Common plastics, such as fossil-fuel plastics are derived from petroleum or natural gas.

Polyethylene or polythene film biodegrades naturally, albeit over a long period of time. Methods are available to make it more degradable under certain conditions of sunlight, moisture, oxygen, and composting and enhancement of biodegradation by reducing the hydrophobic polymer and increasing hydrophilic properties.

Green waste, also known as "biological waste," is any organic waste that can be composted. It is most usually composed of refuse from gardens such as grass clippings or leaves, and domestic or industrial kitchen wastes. Green waste does not include things such as dried leaves, pine straw, or hay. Such materials are rich in carbon and considered "brown wastes," while green wastes contain high in concentrations of nitrogen. Green waste can be used to increase the efficiency of many composting operations and can be added to soil to sustain local nutrient cycling.

Biodegradable plastic Plastics that can be decomposed by the action of living organisms

Biodegradable plastics are plastics that can be decomposed by the action of living organisms, usually microbes, into water, carbon dioxide, and biomass. Biodegradable plastics are commonly produced with renewable raw materials, micro-organisms, petrochemicals, or combinations of all three.

Biocomposite

A biocomposite is a composite material formed by a matrix (resin) and a reinforcement of natural fibers. Environmental concern and cost of synthetic fibres have led the foundation of using natural fibre as reinforcement in polymeric composites. The matrix phase is formed by polymers derived from renewable and nonrenewable resources. The matrix is important to protect the fibers from environmental degradation and mechanical damage, to hold the fibers together and to transfer the loads on it. In addition, biofibers are the principal components of biocomposites, which are derived from biological origins, for example fibers from crops, recycled wood, waste paper, crop processing byproducts or regenerated cellulose fiber (viscose/rayon). The interest in biocomposites is rapidly growing in terms of industrial applications and fundamental research, due to its great benefits. Biocomposites can be used alone, or as a complement to standard materials, such as carbon fiber. Advocates of biocomposites state that use of these materials improve health and safety in their production, are lighter in weight, have a visual appeal similar to that of wood, and are environmentally superior.

Upcycling Recycling waste into products of higher quality

Upcycling, also known as creative reuse, is the process of transforming by-products, waste materials, useless, or unwanted products into new materials or products perceived to be of greater quality, such as artistic value or environmental value.

This is a glossary of environmental science.

Sustainable packaging

Sustainable packaging is the development and use of packaging which results in improved sustainability. This involves increased use of life cycle inventory (LCI) and life cycle assessment (LCA) to help guide the use of packaging which reduces the environmental impact and ecological footprint. It includes a look at the whole of the supply chain: from basic function, to marketing, and then through to end of life (LCA) and rebirth. Additionally, an eco-cost to value ratio can be useful The goals are to improve the long term viability and quality of life for humans and the longevity of natural ecosystems. Sustainable packaging must meet the functional and economic needs of the present without compromising the ability of future generations to meet their own needs. Sustainability is not necessarily an end state but is a continuing process of improvement.

Disposable food packaging

Disposable food packaging comprises disposable items often found in fast food restaurants, takeout restaurants and kiosks, and catering establishments. Food-serving items for picnics and parties are very similar. Typical disposable foodservice products are foam food containers, plates, bowls, cups, utensils, doilies and tray papers. These products can be made from a number of materials including plastics, paper, bioresins, wood and bamboo.

Biodegradable bag

Biodegradable bags are bags that are capable of being decomposed by bacteria or other living organisms.

Biodegradable additives are additives that enhance the biodegradation of polymers by allowing microorganisms to utilize the carbon within the polymer chain as a source of energy. Biodegradable additives attract microorganisms to the polymer through quorum sensing after biofilm creation on the plastic product. Additives are generally in masterbatch formation that use carrier resins such as polyethylene (PE), polypropylene (PP), polystyrene (PS) or polyethylene terephthalate (PET).

Danimer Scientific

Danimer Scientific, formerly known as Meredian Holdings Group Inc. and MHG, is a biopolymer manufacturer headquartered in Bainbridge, Georgia.

Biodegradable athletic footwear is athletic footwear that uses biodegradable materials with the ability to compost at the end-of-life phase. Such materials include natural biodegradable polymers, synthetic biodegradable polymers, and biodegradable blends. The use of biodegradable materials is a long-term solution to landfill pollution that can significantly help protect the natural environment by replacing the synthetic, non-biodegradable polymers found in athletic footwear.

References

  1. "Nature’s way – sustainable polymers and composites" K Kirwan, N Tucker, MR Johnson, Materials World, Vol. 11, No. 10, October 2003
  2. Kirwan, K., "Life’s Work", Engineering, Vol. 246, No.3, pp. 30-31, May 2005
  3. Tucker, N., Kirwan, K., Jacobs, D., Johnson, M., "Addressing the Polymer Waste Mountain – the helix of sustainability and the flowering cell phone", Third International Workshop on Green Composites, March 16–17, 2005, Shin-Daigaku Kaikan of the Imadegawa Campus, Doshisha University, Kyoto, Japan
  4. "Opportunities in Horticulture: A Proposal for Academic Posts in WMG", WMG Report, David Mullins, 26 April 2004
  5. "Environmentally Friendly European Composites Workshop", K Kirwan, N Tucker, M Johnson, C Halstead, D Jacobs, Report, European Science Foundation, April 2004