Background
Plastic usages have increased over the last few decades due to durability, low process, and lightweight. However, rates of their usage and disposal have become matters of environmental concerns. Production of plastic materials consumes a lot of energy. Also, people use and dispose of most plastic materials within the year of manufacture.
From the above observations, we can note that plastic usage has become difficult to sustain. Still, plastics have durable components like polymer that take decades to disappear. Thus, we have large debris of plastics in dumpsites and natural habitats (Thompson, Moore, Saal and Swan, 2009).
Recycling of plastic wastes reduces the effects of plastics on the environment and promotes economic gain. Recycling also reduces other issues such as fuel usages, the number of plastics for dumping, and emission of greenhouse gases. This report focuses on recycling of plastic waste materials, its systems, economic issues, current trends, support, and challenges.
Summary of the Source
The article (Plastics recycling: challenges and opportunities) shows the development of plastic production, usages, and disposal. It notes that we cannot sustain the current trends observed in plastics production, usages, and disposal due to the effects of plastics on the landfill and the environment. It shows recycling systems, economic issues, current trends, supports, and challenges in plastics recycling.
The article also covers waste management in general. It compares recycling against other methods such as “down gauging or product reuse, the use of alternative biodegradable materials and energy recovery as ways of managing wastes” (Hopewell, Dvorak, and Kosior, 2009).
It shows that developments in technology and changes concerning plastic waste management provide new ways of enhancing recycling. Also, efforts of stakeholders such as the public, government, industries, and scientists may change most plastic wastes through recycling with the next few years.
Evaluation
This article contains comprehensive coverage of plastics waste management. It shows the growth in productions, usages, and disposal. It also highlights terminologies used in plastic recycling, systems or types of recycling, economic advantages, current trends, stakeholders’ initiatives, and challenges that face plastic recycling.
This article is a scholarly journal that other scholars have cited in their works. It contains relevant and up-to-date information that have adequate support from other relevant studies.
The article is available from www.ncbi.nlm.nih.gov. This is a reputable Web site that hosts several scholarly journals from various fields. The article has three authors who show a deep understanding of waste management. They support recycling over other forms of waste management. However, they present ideas objectively with supporting evidence.
Plastics Recycling
Plastic recycling is difficult due to the many activities involved. There are four categories in plastics recycling. These are primary, secondary, tertiary, and quaternary recycling. Primary recovery is a mechanical process known as closed-loop recycling that aims at grouping materials with similar properties together.
Secondary recovery focuses on mechanical processes that downgrade products that need low properties. Tertiary recycling involves the recovery of chemical components of plastics. This process is feedstock that involves de-polymerization of polymer to extract various chemicals in plastics.
Tertiary recycling may also involve biodegradable plastics. Finally, quaternary recycling involves “recovery of energy from valorization or wastes” (Song, Murphy, Narayan, and Davies, 2009). Closed-loop recycling mainly involves thermoplastics.
However, we have to recognize that plastics have other materials such as “papers, inks, metals, pigments, and adhesives that make the process complex” (Hopewell, Dvorak, and Kosior, 2009). Closed-loop recycling is effective when handling “polymer materials when there are no sources of contamination, and there is stabilization to protect components from degradation” (Hopewell, Dvorak, and Kosior, 2009).
Manufacturers of plastics mark their products as PET to show suitability for “both bottle manufacturing process and reprocessing to polyester fiber or HDPE for blow molding bottles to show that they are not suitable for injection molding applications” (Hopewell, Dvorak, and Kosior, 2009). Downgrading can help in maintaining the level of polymer in recovered plastic materials.
Feedstock or chemical recycling provides the means of recovering petrochemical components of the polymer. Petrochemical constituents can make new plastics or other synthetic chemicals. However, such byproducts have low economic values.
Systems
There are many methods of recycling plastics depending on the kind of polymer, product, and design of the package. Mechanical recycling can apply in thermoplastic materials like PP, PET, and PP. Mechanical recycling may also involve unsaturated polyester for production of filler materials after re-sizing or pulverization into powder.
This happens because “thermoset plastics cannot undergo re-melting or re-form due to their permanently cross-linked nature” (Hopewell, Dvorak, and Kosior, 2009). It is a challenge to obtain resin from various plastic materials because plastics are not compatible with each other due to “immiscibility at the molecular level, and differences in processing requirements at a macro scale” (Hopewell, Dvorak, and Kosior, 2009).
These challenges involve degrading and formation of solid lumps in mixtures of PET and PVC due to diverse requirements in temperatures that result in bubbles of hydrochloric acidic gas. Therefore, the combination of various plastic materials for the production of resin is technically not feasible.
This process may affect the quality in terms of color, strength, and clarity. Such resin materials require blending with virgin resins for producing materials of non-critical usages such as refuse bags, low-pressure pipes, or materials for applications in protected layers.
Therefore, the purity of recovered plastic wastes influences the quality of resin produced and the use of virgin resin. As a result, the focus has turned to post-consumer recycling for sorting of various plastics depending on the mark of PET, HDPE or PVC. This process aims at eliminating contamination of polymers.
According to the article, post-consumer recycling involves “collection, sorting, cleaning, size reduction and separation, and or ‘compatibilization’ to reduce contamination by incompatible polymers” (Hopewell, Dvorak, and Kosior, 2009).
Economic issues
There are two economic issues affecting plastic recycling. These are prices of recycled plastics and costs of productions. Also, there are also concerns involving quality and quantity. Further, consumers lack information on various applications of recycled plastics. These factors lead to disincentive among consumers.
The main ways of disposing wastes have been incineration or landfill. Costs of these processes differ depending on the nature of the land (geology) and land usages. In some areas, excavations can be expensive. In cities where usages of plastics are high, costs of collections are low due to high densities of populations resulting in the economy of scale.
However, collection depends on locality, sorting facilities, and populations of an area. Countries encourage rural populations to bring their wastes for recycling under ‘bring schemes’ in nearby towns. This is a cost-effective approach in collections than the curbside method. The UK has achieved high rates of collections after the successful initiative of curbside recycling.
The price of oil has effects on productions of virgin plastics. Virgin plastics have high quality than recycled plastics. However, the dramatic “increase in the price of oil has also increased costs of plastic products” (Hopewell, Dvorak, and Kosior, 2009). Oil is the main feedstock in the production of virgin plastics. This implies that recycling is a relatively cheaper option than producing virgin plastics.
Technological developments have also enhanced recycling through decreased costs and improved values of recycled resin. These developments are due to improved efficiency and productivity. Therefore, the economic value of recycling continues to grow as processes of recycling become cheaper than in the past.
Current trends
Generation of plastic wastes is on the increase across the globe. However, the rate of recycling cannot match high rates of usages and disposals. Thus, we cannot sustain this situation (Barnes, Galgani, Thompson and Barlaz, 2009).
Challenges
Recycling industries face challenges in recycling mixed plastic wastes. However, these companies have the abilities to recycle large quantities of wastes. This has been possible due to changes in the post-consumer collection strategies. Plastic designs have been a major obstacle to recycling.
As a result, policies to ensure environmental friendly designs aim at enhancing recycling through collections and packaging that ensure cost reductions during collections to reducing landfill (Shaxson, 2009). This approach should also include durable materials to enhance their recycling through sorting and disassembly.
Rigid packaging discourages the post-consumer collection efforts. This is due to difficulties in collections and sorting. Current collection facilities have challenges involving handling rigid packaging materials due to different techniques needed for handling such wastes.
Low weight and volumes of various plastics like bags and films require expensive facilities that can collect and sort them. However, recycling of plastic films has turned to sources to create a feasible process under favorable conditions.
Effective recycling of films and other flexible plastics require extra investments in specialized facilities that can handle any sort mixed forms of wastes. This process should result in a successful recycling that creates high-quality plastics. However, achieving high levels of purity from the mixture remains a major obstacle.
Post-consumer packaging recycling meets challenges due to various materials, such as PP, PS, HDPE, PET, and PVC. These are rigid materials that are difficult to sort from other materials. However, separating and sorting of all rigid plastic wastes can enhance the quality of recycled resins with low costs and cross-contamination.
Therefore, effective post-consumer collection and sorting can reduce rejection and improve the quality of recycled resins. Further, other materials such as labels and adhesives can increase collection and volumes of recycled materials. Overcoming these challenges can result in high-quality resins, volumes, decrease in waste materials, water and energy usages (Andrady and Neal, 2009).
Support
Recycling has gained support from the public and governments. The public has shown awareness of the need for sustainability in using and manufacturing. Still, governments have formulated policies and schemes to encourage recycling of plastic wastes.
Conclusion
Recycling is a viable strategy for managing plastic waste materials. It is a cost-effective approach that can ensure safe environments. However, recycling faces some challenges related to technology, consumer behaviors, and economic issues.
Recycling remains an alternative to “landfill and other methods of waste management” (Hopewell, Dvorak, and Kosior, 2009). Emerging trends, opportunities, and developments shall improve plastic waste recovery, quality of resin and replace the production of virgin resins in the polymer sector.
References
Andrady, L. and Neal, A. (2009). Applications and societal benefits of plastics. Phil. Trans. R. Soc. B, 364, 1977–1984.
Barnes, A., Galgani F., Thompson C. and Barlaz, M. (2009). Accumulation and fragmentation of plastic debris in global environments. Phil. Trans. R. Soc. B, 364, 1985–1998.
Hopewell, J., Dvorak, R. and Kosior, E. (2009). Plastics recycling: challenges and opportunities. Philos Trans R Soc Lond B Biol Sci., 364(1526), 2115–2126.
Shaxson, L. (2009). Structuring policy problems for plastics, the environment and human health: reflections from the UK. Phil. Trans. R. Soc. B, 364, 2141–2151.
Song, H., Murphy, R., Narayan R., and Davies, H. (2009). Biodegradable and compostable alternatives to conventional plastics. Phil. Trans. R. Soc. B, 364, 2127–2139.
Thompson, C., Moore, J., Saal, S. and Swan, H. (2009). Plastics, the environment and human health: current consensus and future trends. Phil. Trans. R. Soc. B, 364, 2153–2166.