Recycling involves processing used materials into new products in order to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage, reduce air pollution (from incineration) and water pollution (from land filling) by reducing the need for “conventional” waste disposal, and lower greenhouse gas emissions as compared to virgin production. Recycling is a key component of modern Waste Management and is the third component of the “Reduce, Reuse, Recycle” Waste Hierarchy.

Recyclable materials include many kinds of glass, paper, metal, plastic, textiles, and electronics. Although similar in effect, composting or other reuse of biodegradable waste – such as food or garden waste – is not typically considered recycling. Materials to be recycled are either brought to a collection center or picked up from the curbside, then sorted, cleaned, and reprocessed into new materials bound for manufacturing.

In a strict sense, recycling of a material would produce a fresh supply of the same material, for example used office paper to more office paper, or used foamed polystyrene to more polystyrene. However, this is sometimes difficult or too expensive (compared with producing the same product from raw materials or other sources), so “recycling” of some products or materials involves their reuse in producing different materials (e.g., cardboard) instead.

Another form of recycling is the salvage of certain materials from complex products, either due to their intrinsic value (e.g., lead from car batteries, or gold from computer components), or due to their hazardous nature (e.g., removal and reuse of mercury from various items).

Recycling reduces CO2 emissions

A study (2008) by Fraunhofer Institute, Germany, compares the C02 performance of the respective primary and secondary production of the material flows of steel, aluminum, copper, paper, polyethylene (PE), polyethylene terephtalate (PET), glass and wood with each another.

The entire production chain of the mentioned product types was thereby taken into account. Any carbon dioxide emissions by transport are considered additionally.

For all materials, the study established a reduction of carbon dioxide emissions in the recycling process as compared to the primary process itself.

Waste Hierarchy

Waste minimization is the process and the policy of reducing the amount of waste produced by a person, corporate or a society. It is part of the wider aim of waste reduction which is often described as a component of the waste hierarchy.

In the waste hierarchy, the most effective policies and processes are at the top. Waste minimization is also strongly related to efforts to minimize resource and energy use. For the same commercial output, usually when fever materials are used, less waste is produced. Waste minimization usually requires knowledge of the production process, cradle-to-grave analysis (the tracking of materials from their extraction to their return to earth) and detailed knowledge of the composition of the waste.

The main sources of waste vary from country to country. Most waste comes from the manufacturing industry, agriculture, construction, households and demolition industries.

Household waste constitutes a relatively big proportion of all waste, particular in Bahrain. Reasons for the creation of waste sometimes include requirements in the supply chain or special food packaging due to regional needs. For example, a company handling a product may insist that it should be packaged using particular packing because it fits its packaging equipment.

In contrast to waste minimization, waste management traditionally focuses on processing waste after it is created, concentrating on re-use, recycling, composting and waste-to-energy conversion.

Industries, using more efficient manufacturing processes and better materials, will generally reduce the production of waste. The applications of waste minimization have led to the development of innovative and commercially successful replacement products. Waste minimization has proven beneficial to industry and the environment:

Waste minimization often requires investment, which is usually compensated by the savings. However, waste reduction in one part of the production process may create waste production in another part.

There are no government incentives for waste minimization, which focus on the environmental benefits of adopting waste minimization strategies.

Recycling Paper

In terms of quantity, recovered paper is the most important raw material nowadays.

The majority of the world population uses less than 40 kg of paper per person and year. Despite the use of electronic media, this amounts to more than e.g. 200 kg per person in Germany.

In 2007, 23.2 million tons of paper, paperboard and cardboard were manufactured, 15.8 million tons of that from recovered paper, thus around 68 %. As the largest paper manufacturer in Europe, Germany is also the forerunner in terms of the recovered paper utilization rate. At the same time, this also demonstrates the importance of recovered paper as a raw material.

Reduction of CO2 emissions

As compared to other materials, the carbon dioxide emissions are low in the manufacturing of paper. Yet both the water and the energy use are significantly lower in the manufacturing of paper fiber in the recycling process than in the primary production. However, the file-span of fiber is limited to live to seven recycling cycles. In a comparison of the CO2 performance, the transport processes involved in the collection and delivery to paper factories are above all of consequence for the secondary process. Yet when very critically examined, the reduction still amounts to around 90.00 kg CO2 per ton of paper. Moreover, the use of recovered paper protects the forests that provide a substantial contribution to the absorption of carbon dioxide, which was not yet taken into account in this report.

Primary Process Recycling Saving
0.17 tons/CO2 0.08 tons/CO2 0.09 tons/CO2

Recycling Plastic

Polyethylene (PE)

Sophisticated recycling techniques allow for the processing and re-utilization of used plastics such as polyethylene.

Approx. 245 million tons of plastics were produced world-wide in 2006, nearly 30% of them polyethylene. PE is used as a packaging material, but is also employed in electrical, construction, machine, and vehicle engineering.

Reduction of CO2 emissions

With the contemporary recycling processes, PE can be recycled four to five times. Afterwards, the decreasing length of the molecule chains no longer permits any further recycling. An exemplary analysis of PE with low density (LDPE) – which is wide-spread in the form of foil as a packaging material- shows that a reduction of 1.19 tons of CO2 per ton of polyethylene is achieved in the secondary process. This corresponds with a reduction of around 70%.

Primary Process Recycling Saving
1.69 tons/CO2 0.50 tons/CO2 1.19 tons/CO2

Polyethylene Terephtalate (PET)

Increasing crude oil prices and finite resources are making it increasingly important of recycle plastics such as PET.

An estimated 4% of the global oil consumption world-wide is used to produce plastics. The plastic polyethylene terephtalate is a popular material used in beverage bottles, textile fibers, food packaging, foils, among other things.

Reduction of CO2 emissions

If the production of PET granulate in the primary and secondary process are compared, the reduction of carbon dioxide amounts to almost 88% – even if the sometimes long transport paths to Southeast Asia are taken into account. The production of 1 ton of PET releases 4.10 tons of CO2. Around two thirds of the recycling PET can be found in textiles, the rest in foils, plates, bottles, tapes, and other products. PET can thereby undergo up to eight recycling processes.

Primary Process Recycling Saving
4.10 tons/CO2 0.47 tons/CO2 3.63 tons/CO2

To calculate an average saving in CO2 emissions we are considering a mean value for a typical mix of different plastic as follows:

Product Quote Primary Process Recycling Process Saving
PE 50% 0.85 tons/CO2 0.25 tons/CO2 0.60 tons/CO2
PET 50% 2.05 tons/CO2 0.24 tons/CO2 1.82 tons/CO2
Total 100.00% 2.90 tons/CO2  0.49 tons/CO2  2.41 tons/CO2 

Recycling Metal


In terms of sustainability, steel offer excellent preconditions: After all, steel can be infinitely recycled without a loss in quality.
Yet scrap metal is also used in the primary production of steel from iron ore in blast furnaces (so-called oxygen steel procedure). Depending on the availability of the sought-after secondary raw material, it accounts for up to 20 % of the input material.

Reduction of CO2 emissions

With regard to carbon dioxide emissions from the recovery of iron ore to the production in the blast furnace, approx. 1.54 tons of C02 are produced per ton. During the collection, treatment and processing of steel scrap, this figure is reduced to approx. 0.68 tons of C02 per ton of crude steel, which corresponds with a reduction of 0.86 tons of C02, thus around 55%.

Primary Process Recycling Saving
1.54 tons/CO2 0.68 tons/CO2 0.86 tons/CO2


Measured by absolute C02-reductions, aluminium scrap is the top performer among the analyzed secondary resources.
After steel, aluminium is the most frequently used metal in the world. In 2006 approx. 34 million tons of aluminium was produced world-wide, around 23% of that as secondary aluminium. Furthermore, so-called aluminium metal casting, e.g. in the production of car wheel rims, also plays a role – with a share of approx. 80% secondary alloying. The energy consumption to produce 1 ton of aluminium is at least 13,000 KWh and the typical local energy mix creates emission of about 0.5687 kg of CO2/KWh.

Reduction of CO2 emissions

Aluminium scrap can be remanufactured almost loss-free with approx. 7% of the manufacturing energy of the primary process and nearly without a decrease in quality. As a result, approx. 9.87 tons of C02 are saved per ton of aluminium in the recycling process – and thus over 93%. Depending on the smelting plant, this reduction may be even higher in individual cases.

Primary Process Recycling Saving
10.60 tons/CO2 0.73 tons/CO2 9.87 tons/CO2


Due to its diversity, copper has always been very popular and therefore also a very valuable scrap metal.

Copper is easily mould able, corrosion-resistant, forgeable, and an excellent conductor of heat and electricity. An additional positive feature of copper was already proven by the Colossus of Rhodes: that copper is perfect for re-melting. Nowadays, 35% of the 17 million tons of copper processed world-wide each year already result from the recycling of copper scrap.

Reduction of CO2 emissions

The C02 comparison also turns out positively in the case of copper recycling: the secondary process saves approx. 3.52 tons of C02 per generated ton of copper and thus 36% more than the primary production process from copper ore. When copper scrap is melted down, a maximum of 5% of the material is lost, which signifies a high degree of efficiency. At the same time, there are practically no differences in quality between primary and secondary copper.

Primary Process Recycling Process Saving
5.50 tons/CO2 1.98 tons/CO2 3.52 tons/CO2

To calculate an average saving in CO2 emissions we are considering a mean value for a typical mix of different metals as follows:

Product Quote Primary Process Recycling Process Saving
Steel/Ferrous 25% 0.39 tons/CO2 0.17 tons/CO2 0.22 tons/CO2
Aluminium 60% 6.36 tons/CO2 0.44 tons/CO2 5.92 tons/CO2
Copper 15% 0.83 tons/CO2 0.30 tons/CO2 0.53 tons/CO2
Total 100.00%  7.57 tons/CO2  0.91 tons/CO2  6.67 tons/CO2 

Recycling Glass

Traditionally, glass has been used to package liquid beverages because, being an inert material, it does not alter the chemical properties of its content. The production of glass bottles includes the extraction and transport of raw materials and the melting of these materials to produce glass. Melting the raw materials requires large amounts of energy, usually provided by fossil fuels which when combusted release CO2.

Reduction of CO2 emissions

The production of 1 ton of Glass bottles releases 3.20 tons of CO2. When glass is recycled, however, there is no need for extraction of raw materials and the overall temperature needed to melt glass cullet (broken or waste glass returned for recycling) is significantly less than that needed to melt ‘virgin’ raw materials. Glass bottles can be recycled indefinitely. If comparing the production of Glass in the primary and secondary process, the reduction of carbon dioxide amounts to almost 80%.

Primary Process Recycling Saving
3.20 tons/CO2 0.61 tons/CO2 2.59 tons/CO2

Recycling Wood

With an almost 99%C02 reduction compared to the primary process, waste wood recycling yields the best result of all studied material flows.

Mixed forests can absorb about four kg of C02 per m2 and per year and tropical dry forests even up to 20 kg. The same volume respectively is released during the combustion process, which makes the recovery of energy from wood a C02 neutral process.

Reduction of CO2 emissions

Waste wood can be recovered for energy purposes to generate electricity and heat. During the corresponding primary process, the distribution of the energy sources was analyzed in the generation of electricity and heat in Germany. As regards the material recycling of waste wood, the primary and secondary production of chipboard was considered. Taking into account the relationship between these two recycling approaches, the report revealed that 0.01 tons of C02 ware emitted in the secondary process, thus resulting in a reduction of approx. 0.77 tons.

Primary Process Recycling Saving
0.78 tons/CO2 0.01 tons/CO2 0.77 tons/CO2