According to the EC (19 November, 2008) “waste means any substance or object which the holder discards or intends or is required to discard.” Recycling materials and products – that are considered waste - is an ancient practice which shows that in times of resource scarcity (i.e. shortage of virgin materials) societies attach more economic and societal value to their own waste. This implies that throughout time the definition of waste can change as well. Generally speaking longer use or re-use of materials and products this is often mainly to cover a society’s needs.
To put it differently, recycling is a process which reconsiders the current life cycle of creating products and materials and associated process and final waste. Ideally, products and materials should be designed, produced, used and disposed in such a way that they can be completely re-used and/or recycled effectively and efficiently. There are many waste types , such as basic materials (i.e. glass, paper, steel, aluminum, construction minerals and plastic but also water), hazardous and chemical wastes, but also end-of-use waste products (i.e. e-waste , furniture, cars and textiles) that can be re-used or recycled.
Although recycling as part of the waste management predominantly is a question of which technologies or procedures to deploy, real world practice shows that recycling is even more a socio-economic question of how much a society is willing and able to pay for sanitation, waste collection and waste processing as around the globe there already has been extensive experience with recycling processes and technologies.
There are a number of technologies that can be integrated into a waste management strategy. For waste collection waste bins, garbage bags and containers can be used, for waste transport logistics , trucks, trains and ships are generally applied. Waste processing technologies/processes vary from re-use outlets (e.g. second-hand furniture, clothing and other consumer products), waste component and material re-use (e.g. plastics and metals), organic waste composting , waste incineration, waste gasification  to waste disposal in land-fills .
In trying to establish a proper waste management system that is geared towards optimal recycling rates many international bodies and governments promote the application of a so-called waste hierarchy.
In its Waste Directive 2008/98/EC  the European Commission applies the following hierarchy:
(a) prevention; the formulation of a product eco-design policy addressing both the generation of waste and the presence of hazardous substances in waste, with a view to promoting technologies focusing on durable, re-usable and recyclable products;
(b) preparing for re-use; to promote the re-use of products and preparing for re-use activities, notably by encouraging the establishment and support of re-use and repair networks,
(c) recycling; to promote high quality recycling and, to this end, shall set up separate collections of waste where technically, environmentally and economically practicable and appropriate to meet the necessary quality
standards for the relevant recycling sectors. Separate collection shall be set up for at least the following: paper, metal, plastic and glass
(d) other recovery; waste incineration, and other energy recovery techniques, such as pyrolysis, combined with energy recovery;
(e) disposal; where recovery in is not undertaken, waste undergoes safe disposal operations which safeguards the protection of human health and the environment.
In most industrialized economies waste management is increasingly geared towards recovery/recycling, instead of incineration and disposal. In some economies there already are well-organized recycling businesses and processes in place for a range of products (e.g. furniture, clothing textile, etc.) and materials (e.g. paper, iron, glass and steel there are already existing recycling). Such practice shows that many of the technologies and processes used are technological feasible. However, this largely depends on the type and composition of waste being processed. For instance hazardous waste (e.g. chemical and nuclear) processing is costly and often not a type of luxury that every country can afford. Other types of waste such as municipal solid waste are highly heterogenic and more difficult to recycle as it is economically not (yet) feasible to separate or filter out all recyclable waste fractions with a positive market value so that the recycled product cannot compete with virgin materials or products.
Operational barriers for recycling processes are thus often of non-technical nature and demands a high degree of coordination and organization of the waste management chain. However, simply copying and pasting recycling advanced recycling technologies and practices from abroad does not necessarily lead to optimal results. One of the factors that is crucial for waste processing is the composition of the waste being processed. Simply stated, this means that not all recovery technologies can be used for processing all types of waste. To illustrate a couple of the main differences in the composition of waste between industrialized and developing countries is that the density of the waste in developing countries is 2-3 times greater than in industrialized countries as well as the moisture content. Also developing country waste has a significantly higher fraction of organic waste, dust and dirt as well as a smaller particle size than in industrialized economies.
For some specific wastes many dedicated so-called ‘end-of-pipe’ recycling lines have been developed. Examples of such dedicated lines are, plastic bottles (i.e. PET), and the ones difficult to recycle paper-aluminium liquids container recycling lines (i.e. tetra pak), glass recycling, aluminium, steel, copper, etc. Each of these recycling lines has to meet specific operational requirements in order to function properly. In response to the often great technological end-of-pipe recycling challenges posed by certain difficult-to-separate waste types is that technology developers are moving more upstream in the waste cycle so as to produce those products and materials that more easy to separate, re-use and recycle. In the waste hierarchy this would imply a higher focus on waste prevention.
Given the wide array of individual technologies and processing lines that can be potentially used for recycling of specific waste streams it is difficult to provide a clear-cut description of the status of recycling technologies. However, on a global level there is extensive experience with waste recovery technologies, like composting (1 , 2 , 3 ), glass- (1 ,2 ,3 ), metals- (1 , 2 , 3 ), plastics- (1 , 2 ,3 ) and water-recycling (1 ,2 ) as well as waste incineration and landfilling (see, image below) which shows that recycling as a technological concept can be considered proven.
Source: EUROSTAT, 2010.
Future market potentials for waste recovery and recycling technologies can be partially based on current recycling rates. Theoretically a 100% recycling rate to satisfy demand would imply that when a product or material enters its end-of-life stage at virtually the same time it will be recovered and re-used in the usage cycle. However, with growing global demand such a ‘one unit out and one unit in’ principle (i.e. 100% recycling rates) is unlikely as end-of-life dates are difficult to predict. Metals for instance have a high durability and and could remain embedded in construction materials for decades before becoming available for recycling. Nonetheless, higher recycling rates are generally associated with a higher level of sustainability as re-use reduces the environmental pressure on usage of virgin materials and resources.
The European Copper Institute in 2008 published a communication with data suggesting that “42% of the copper usage in Europe is met via recycling”, whereas Asia and North America had recycling rates of respectively 38 and 32%. Subsequently, there is still a considerable potential to copper increase recycling rates and thus to introduce new and innovative copper recycling processes and technologies into this sector. In the European paper industry recycling rates are up to 66% in 2010 from 53% in 2000 (ERPC , 2010). For the destination of post-consumer PVC (polyvinyl chloride ) waste in the EU data suggests a recycling rate of only 3%, with the rest of the PVC waste either being incinerated (17%) or landfilled (80%).
For the European glass industry collection and recycling rates are presented in the figure below. Optimizing re-use and recycling of glass at some point goes beyond standard collection methods (i.e. glass-collection bin). An EU funded research project attempted to use innovative technologies to separate the cathode tube from the other parts of the television, cutting the tubes along the line where its two different types of glass are joined. After a glass cleaning process about 90% of the resulting glass proved to be recyclable.
Source: FEVE, 2010
Data for household packaging recycling in Flanders, Belgium (EC, 2008) show large increases in recycling rates from 1995 to 2006. Where in 1995 28,1% of household packaging was recycled (25,6% incineration with energy recovery and 46,3% disposal in landfills) in 2006 the recycling rate was up to 83,9% (with 10,4% for incineration and 5,6% landfilling). This example shows that in some circumstances, a vibrant market in recycled products can be observed. However, other extremes exist as well. For instance, in the United Kingdom, less than 3% of portable batteries are collected for recycling, which leaves significant market potential for innovative approaches.
For those economies that are considering improving and/or implementing, recycling technologies and practices, the activities could contribute to:
- More efficient use of scarce (natural) resources such as metals and minerals (e.g. It only takes 1.3 ton of used oil - compared to ten ton of crude oil - to produce one ton of high-grade base oil for the lubricant market; EC 2007),
- Lower air and water pollution impact due to avoidance of primary production processes, such as mining, quarrying, processing, etc.,
- A reduction of energy use in the material/product production process (e.g. the copper recycling process results in energy savings of up to 85% compared to primary production; ECI 2008),
- A lower level of GHG emissions (associated with lower energy use) of recycled materials (i.e. secondary market) compared to the primary market,
- Increased employment associated with handling and processing of waste streams, additional employment could be in waste collection, waste handling and processing, secondary material/product trade (e.g. second-hand store); the exact employment effect depends on the recycling technology/process chosen related to current existing waste management practices in the area, etc.
In general, there is a significant potential for reducing GHG-emissions through recycling processes, due to reduced process energy consumption. Primary production processes for intermediate products such as aluminum production require large amounts of energy input to melt the raw material (i.e. bauxite). Recovering and melting secondary aluminum requires much less energy as the scrap aluminium  is already of high purity (as compared to bauxite). Lower energy consumption in turn implies lower CO2-emissions. For many other recycling processes, such as glass, paper, plastics, etc. a similar argument can be made.
The GHG impact of the production of other waste categories, such as old washing machines, computers, mobile phones, etc. can theoretically also be significantly reduced by means of improving the production processes. However, as most e-wastes also use energy during the user stage the efficiency of the appliance  is also an important factor to consider when assessing the GHG-impact of electronic products during their life cycle.
When looking at the CDM project pipeline , there are few project activities that involve some form of waste recovery or recycling. Waste related projects in de pipeline include waste-to-energy projects by means of incineration  or gasification  or methane capture at landfill sites. Other CDM project activities relate to the use of either biomass from virgin sources or secondary biomass waste streams, generally for the production of bio-energy. The associated methodologies of these waste management technologies/processes can be used for quantifying the GHG-impact. Standard methods or protocols for quantifying the GHG-impact of recycling projects and practices are scarcer, although they almost by no exception follow the guiding principles of a life cycle assessment (LCA ).
A study by Patel, M., et al. (2010), shows an analysis of “the environmental impacts of bottle-to-fibre (B2F) recycling”. In this study four plastic bottle (PET) recycling technologies were investigated (i.e. mechanical recycling, semi-mechanical recycling, back-to-oligomer recycling and back-to-monomer recycling), where the LCA results were compared with a production process based on virgin material. Based on three levels of analysis for assumed system boundaries and selected technology, recycled PET fibre can reduce the GHG emissions impact of PET bottles with 25-75% compared to virgin PET (in addition to a non-renewable energy saving of 40-85%). In literature there are many more LCA analysis being done for specific recycling configurations on a multitude of life cycle impact categories including GHG-emissions (1 ,2 ,3 ,4 ,5 ).
The economics of waste management practices and specifically recycling activities are often a crucial factor in successful adoption of a new process or technology. In general, there are many factors that shape the financial and economic environment for recycling initiatives. In some cases basic legislative changes, such as closure of a nearby landfill site or a regional ban on landfilling can make recycling more attractive as the costs of waste disposal go up. Other general examples that change the competitive environment are subsidies and taxes for specific technologies, such as waste incineration. In some areas in Europe, where landfilling is banned waste incineration has gained significant attention in recent years. New and more innovative recovery and recycling practices have to ready to compete with the already proven practice of waste incineration.
Given the wide variety of waste types a multitude of recycling processes is possible. Therefore it is difficult to provide clear-cut cost figures for recycling practices. The economic viability of recycling can only be proven on a case-specific basis, as the local context is one of the crucial factors for investment decisions. For example, investment costs relate to the commercial loan interest rates (possibly with risk premium for novel business models) charged by local financial institutions and the economic and monetary stability of the country of investment. Additionally, the costs of labor for construction as well as local availability of construction materials and machinery determine the financial requirements and costs for the investor.
It is in the policy makers interest to try and stimulate the various actors in the market to start to invest in recycling. One of the main targets in liberalized economies is to optimize the market structure. For a comprehensive overview of a number of waste-recycling markets in the EU, see the 2008 report of the European Commission (DG Environment) on ‘Optimising markets for recycling ’.
- Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on waste and repealing certain Directives
- European Commission (EC), 2008 – DG Environment, ‘Optimising Markets for Recycling’.
- ERPC, 2010, The European Recovered Paper Council, ‘facts and figures’; http://www.paperrecovery.org/facts/erpc_facts_figures.asp?folderid=527 
- EUROSTAT, 2010, waste statistics; http://epp.eurostat.ec.europa.eu/statistics_explained/index.php/Waste_statistics 
- FEVE, The European Container Glass Federation, 2010, ‘statistics’; http://www.feve.org/index.php?option=com_content&view=article&id=10&Itemid=11 
- European Copper Institute (ECI), 3 June 2008, press release; http://www.eurocopper.org/files/pr_copper_recycling_rates_030608.pdf 
- European Commission (EC), 2007, ‘LIFE and waste recycling, Innovative waste management options in Europe’; http://ec.europa.eu/environment/life/publications/lifepublications/lifefocus/documents/recycling.pdf 
- M. Patel et al., June, 2010, ‘Open-loop recycling: A LCA case study of PET bottle-to-fibre recycling’ Elsevier B.V., Resources, Conservation and Recycling.
- http://www.climatetechwiki.org 
- http://www.wikipedia.org 
- http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CONSLEG:2000D0532:20020101:EN:PDF