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Closed loop recycling[edit]

Recycling symbol


Closed loop recycling can be defined as an essential waste management for environmental protection which is a production system with recycling process[1] . The attention of strategy is shifting from disposing waste to recovery and reproduce by considering the recyclable waste is potential. In order to obtain an equilibrium of economic growth and natural resource consumption, the resources should be utilized effectively and it requires realistic management of waste is potential new resource[2] The closed recycling loop is formed by collecting recyclable materials, transforming into a new product and arranging the waste back into consumer circulation. It extracted post-consumer waste or byproduct of other process then recycles these items and produces into new products, such as recycling magazine or newspapers to produce other types of paper or paper-board. It also ensures the recyclable resources are valuable and they are able to be recycled and re-purposed into the same products.[1] In the economy perspective, closed loop recycling system is a sustainable concept that certain recycling and recovery measures to maintain the materials are useful as long as possible and reduce the burdens of the environment. It means the materials can be recycled indefinitely with no degradation of quality and properties, this major condition allows the recyclable product conversion of the same product as pre-consumer.[3] The most suitable materials of closed loop recycling are aluminum, glass and plastic as they will not lose the quality during the recycling and reproducing process. Furthermore, biodegradable disposal is another phase of closed loop recycling system that unrecyclable materials and byproduct which is useless in production will be break down into natural materials return to the environment without pollution and deleterious impacts.[4] Comparing to open loop recycling, closed loop recycling protects the quality loss for new product rather than the reduced functionality.[5] Also, closed loop recycling system contains various benefits that reduces the engagements of original materials and protect the environment. [4]

Process[edit]

Closed loop recycling technique is repeatedly recycling and reusing materials instead of down cycling, its process is to maintain material engaged in a loop arrangement to support a circular economy. Recycling and reusing throughout the whole process rather than used only once and turned into waste.[6] The principles of the process are collection, manufacturing and supplying, and the collection phase is to divert and gather recyclable materials to support the operation of the process.[5] The recycling factories obtain the resources by collecting the waste form homes, businesses and recycling banks. Further, manufacturing phase classifies recyclable materials and apply into the production of new products and the manufactures supply the new products to the third party.[5] In the management of the closed loop supply chain, the demand of products and operation efficiency is affected directly by the value of recyclable waste resources and the price strategy.[7] . The symbol of the recycling is the representation of the closed loop recycling that is three arrows chased each other[7]. The arrows symbolized 3 elements based on the concept of closed loop recycling system which are collecting, manufacturing and purchasing. It is non negligible that no accumulation of contaminants or toxins will present in the multiple loop of closed loop recycling to reduce the secondary safe of manufacturing products. [7]

To examine the consequence of the closed loop recycling progress, the government formulated recycling policies with a wide range of indicators.[2] One of main indicators is the recyclability benefit rate that highlights the potential environment savings which can be achieved through recycling and reproducing.[2] The estimation of environment influences is based Life Cycle Assessment practices that engaging the Cumulative Energy Extraction from the natural environment, also quantify the environmental effect from the perspective of resource consumption. Overall, the result of the investigation expresses that closed loop recycling process is more efficient and beneficial than land filling and incineration.[8]

Main recyclable product
Material typeGlass
Physical properties
Density (ρ)2.5 kilograms per cubic meter
Water absorption—over 24 hours>120%
Thermal properties
Melting temperature (Tm)600~800°C

Effect[edit]

Reapply and reproduce system of closed-loop recycling promotes environmental sustainability and conserve the natural resources[9]. It minimizes the dumping of the non-degradable waste into the natural ecosystems, maximizes the value and practicality of recycling products. [9] It preserves the natural resources of the earth, such as precious metals, minerals, and wood to reduce the requirement of landfill and incinerate and reduce air, water pollution and the emission of greenhouse gasses.[10] Moreover, the less consumption of resources decreases the risk of harm to the environment and wildlife.[9] It also enables material of high-quality to preserve in circulation ensures that there is a demand in the environment for these varieties of materials and this strategy is applied in multiple scopes. To be specific, the system reduces the application of virgin materials, saves occupancy space for non-recyclable materials, and reduces pollution in the environment as creating materials from original resources is more labor intensive than recycling post-consumer waste and it produces more emissions. [9]

In the aspect of economic, a circular flow of materials and energy in closed loop recycling process are endorsed for environmental to obtain the monetary benefits of saving the expenses.[10] For example, the price of polyethylene impact on the fluctuating cost of oil as the production cost of polythene products has increased dramatically in the last few years.[8] However, closed loop recycling decreases the dependency on virgin material that 1.8 tons oil will be saved for every ton of recycled polythene. Thus, closed loop recycling program maintain the economic sustainability which means reducing water engendering, enhance the efficiency of manufactures to depress the prime cost. Due to more resources and energy available for society by recycling in closed circulation, there are various employment generated that accelerates the development and sustainability of the society. [8]

Example[edit]

Closed loop recycling strategy of environmental protection is applied in multiple range, such as fuel alcohol production, nutrient recycling from microalgae biomass as well as discontinuous carbon fiber polypropylene composites .[9] A basic example of it is the recycling of aluminum, such as cans which can be recycled and reproduced into a new can with few material degradation or waste creation. Another example is the production of plastic products which is almost 3.7 million tons each year. The grocery industry demonstrated that the consumers utilized at least 69% of produced 1 million tonnes of plastic in a year which equate to 9 billion carrier bags. In past five years, the manufactures focused on recycling plastics and the recycling rate has significantly increased[8].Closed loop recycling system saves 7.4 cubic yards of landfill space by recycling one ton of plastic. Due to closed loop recycling system, plastic products can be recycled several times that save irreplaceable resources for each time. This is closing the loop as resources are re-purposed into new materials without the landfill.[8] Hence, the closed loop recycling dramatically decreases the occupancy space, economizes the prime cost of manufacture and promote the economic efficiency.[8]


Sydney ANZ Stadium is the precedent for recycling and environmental initiatives among stadiums in NSW by engaging closed loop recycling program.[6] It implemented in 80,000 seats at Homebush Bat site that successfully collected and recycled 150 tones waste which can save 2.3 million liters water. The achievement is equal to 18 cars permanently taken off the road and the electricity switched off of 120 houses for one year. The stadium also recycled rain water to flush toilets and irrigate the pitch, increase the use of energy-efficient lighting and energy-efficient power to support environmental protection. Additionally, the Australian company Closed Loop delivered the closed-loop program to ANZ Stadium caterers which involve the provision of recyclable packaging, recycling education programs.[6] They also provide closed-loop bins placed in back-of-house areas and public locations to capture recyclable waste and organic food waste[6]. The company ensure that only recyclable food and beverage packaging are applied to serve meals and drinks in ANZ Stadium. This packaging is then captured by the recycling bins located throughout the stadium and recycled into new end-use products.[6]

Recycling bottles and cans

In addition, waste glass bottles recycling is the most common instance but difficult to solve by the increasing population and consumption.[7] Collecting broken glass and glass products is not consistent process and household waste glass will be progressed with other unrecyclable garbage.[7] The certain sections of recyclable glass resources will be melted in a high-temperature condition and reproduced and reused as the same products as post-consumer or other types of products in different purpose. The other unrecyclable glass material will be crushed down and cause secondary solid pollution to the soil and atmosphere.[7] According to statistics, the average glass product recycling percentage of the world is approximately 50%, such as German has reached at 97% and Taiwan (China) is obtaining 84%. Closed loop recycling system has evidently been an assistance of the nations to disposal glass waste, decrease the expense of glass production and improve the environmental condition. However, due to the developing garbage classification and extraction technique, the glass recycling rate is only 13% for China. In details, the glass waste in a city of China is over 7 million tons per year but the recycling proportion is merely 3%-5% of the total municipal waste. [7]

Comparison[edit]

There are a number of different recycling system or recovery solution available to maintain the economic resources as long as possible.[5] Closed loop recycling and open loop recycling are two such methods that products and materials are turned into new products of the same quality or reduced functionality.[5] The main differences between closed loop recycling and open loop recycling are open loop recycling requires downcycling process and applications of the materials recycled by open loop will not be the same as before recycling. Specifically, open loop recycling refers to a recycling process which the recycled materials are converted into another original materials and waste product. The reproducing process recycles the materials into another product with different purposes from their pre-recycled purpose.[5] The typical materials recycled in open recycling circulation into the recycling process as the input is converted to a new raw material, which can only be used into other manufacturing progresses. The phases of open loop recycling involve processing various similar types of products that composes and change the properties of the material itself through heating, chemical reactions, or physical crushing. [10] The most familiar example of open loop recycling is recycled plastic bottles being reproduced into fleece fabric for jackets.[10] This process is defined as “open loop” because the fleece jacket is made from the recycled bottles which cannot be recycled again. [10] The government recycling project basically applied open-loop recycling system that the materials utilized to produce single-use manufactured goods exit the supply chain of the operation once the consumers purchase the products. [2] These products then have been recycled with certain material of other similar goods containing rather than the desired recyclable material that lead to the consequence of waste. Also, open loop recycling is defined as downcycling or reprocessing that associated with a degradation of functions, loss of quality and remaining attached materials which cannot be recycled. [2]

While open loop recycling solutions is the most suitable option for companies with the concern of diverting waste from landfill or incineration. However, in order to achieve real longevity for the resources, closed loop recycling is more environmental friendly[4]. Closed-loop recycling focuses on all the materials in manufactured goods can be recycled and reused in identical role as before.[4]  Closed loop recycling maintains the sustainability of supply chain and the system support the recyclable materials can be developed as the same type of products as before. Closed-loop recycling is common in specialized industries, such as the computer and battery industries which is applying expensive or complex goods that cannot easily be broken down post-consumption into constituent materials. Closed loop recycling also focuses on recycling and reusing the products without material quality loss. It is an opportunity to recapture and repurpose products instead of simply tossing them as waste.[4] According to The Penn State scientists, they highlighted a genuine closed loop recycling process can be processed indefinitely without properties deteriorating. Closed loop recycling is more environmental friendly and open loop recycling is also necessary as only few products are able to be recycled in closed loop which is without loss of quality and functionality.[4]

Reference[edit]

  1. ^ a b Lamanria, F.P (2010). "Closed loop recycling:A case study of films for greenhouse". Polymar and Degradation: 285-288.
  2. ^ a b c d e Huysman, Sofie; Debaveye, Sam; Schaubroeck, Thomas; Ardente, Fluvio; Mathieux, Fabrice; Dewulf, Jo; DeMeester, Steven (22 May 2015). "The recyclability benefit rate of closed loop recycling and open-loop systems: A case study on plastic recycling in Flanders". Resources, Conservation and Recycling. doi:10.1016/j.resconrec.2015.05.014.
  3. ^ "5.2. Recycling: open-loop versus closed-loop thinking | EME 807: Technologies for Sustainability Systems". www.e-education.psu.edu. Retrieved 2019-05-16.
  4. ^ a b c d e f Bruno, Lacarriere (2015). "Emergy assessment of benefits of closed-loop recycling accounting for material losses". sydney.primo.exlibrisgroup.com. Retrieved 2019-05-16.
  5. ^ a b c d e f Min, Huang (2013). "Analysis for strategy of closed-loop supply chain with dual recycling channel". sydney.primo.exlibrisgroup.com. Retrieved 2019-05-16.
  6. ^ a b c d e "ScienceDirect". www.sciencedirect.com. Retrieved 2019-05-16.
  7. ^ a b c d e f g Wenxue, Ran (2016). "A study of the closed-loop recycling supply chain coordination on waste glass bottles recycling". sydney.primo.exlibrisgroup.com. Retrieved 2019-05-16.
  8. ^ a b c d e f Iqbal, Marie (2012). "Closed-loop recycling of recycled concrete aggregates". sydney.primo.exlibrisgroup.com. Retrieved 2019-05-16.
  9. ^ a b c d e "ScienceDirect". www.sciencedirect.com. Retrieved 2019-05-16.
  10. ^ a b c d e Rhys.J, Tapper. "Development of a closed-loop recycling process for discontinuous carbon fibre polypropylene composites". www.sciencedirect.com. Retrieved 2019-05-16.