DESCRIPTION
A BASIC OVERVIEW OF OUR PROJECT
Project Inspiration
In India, the Indian Railway Catering and Tourism Corporation (IRCTC), "Rail Neer", a popular PET water bottle, has amassed a revenue of Rs. 1,500 million and more through the packaged water business. With each bottle priced at Rs. 15, more than 100 million Rail Neer bottles are sold yearly [2].
To look at Rail Neer consumption and to assess PET disposal systems, we visited the Katpadi Junction and upon interaction with local vendors selling drinking water in PET bottles (both Rail Neer and other brands), we found that around 500 bottles were sold on average per day; furthermore, the vendors were unaware of the subsequent PET disposal processes. PET shredding machines placed around Katpadi Junction to dispose of the bottles were also in disuse. This brought us to light on the issues surrounding PET recycling, not only in the railways, but throughout India.
It is estimated that 8300 million metric tonnes (Mt) of virgin plastics have been produced to date, with 6400 Mt of plastic waste having been generated as of 2015 [1].The plastic paradox has posed itself as a conundrum because its essentiality to daily life outweighs its unsustainable nature. Our dependency on plastics has crippled our need for boycotting the same due to its durability being a desirable feature, the same feature that is posing a significant threat to our environment.
Microplastics fragments of plastic that are less than 5 mm long and primarily occur for two reasons: direct generation of microplastics and generation from a secondary source, usually due to the breaking down of large plastic debris by weathering. The harmful impact of microplastics on human health is currently being established, and its highly toxic nature is well known [3]. The small sizes of microplastics make them simple to consume. They are resistant to biodegradation, which allows them to survive in the environment and migrate easily through the food chain. Additionally, once released into the environment, microplastics are nearly impossible to remove because they range in size from micron to nanometer. These traits make microplastics potentially dangerous for both people and the environment. Microplastics offer a concern to marine species, who may unintentionally ingest them and suffer physical and mechanical injury (such as anomalies in internal organs) as a result [4]. In a year when the plastic conundrum takes centre stage, we thought it pivotal to devise a method to tackle PET bottle pollution.
Defining Problem
Around 32.21 million tonnes of polyethylene terephthalate (PET) are produced worldwide annually to create disposable beverage bottles, packaging materials, garments, and carpets. As a recyclable plastic, it is used as a packaging material in 78.8% of water bottles. While PET is regarded as one of the most recyclable materials, with India recycling over 80% of its PET bottles, over 2.8 lakh tonnes are nevertheless wasted and end up in dump yards and landfills. The most common reason PET bottles are opted for based on our survey was their cheap and economical, followed closely by their flexibility and durability. While bioalternatives exist, PET plastics are here to stay as it is a behavioural tendency to rely on them.
Around 32.21 million tonnes of polyethylene terephthalate (PET) are produced worldwide annually to create disposable beverage bottles, packaging materials, garments, and carpets. As a recyclable plastic, it is used as a packaging material in 78.8% of water bottles. While PET is regarded as one of the most recyclable materials, with India recycling over 80% of its PET bottles, over 2.8 lakh tonnes are nevertheless wasted and end up in dump yards and landfills. The most common reason PET bottles are opted for based on our survey was their cheap and economical, followed closely by their flexibility and durability. While bioalternatives exist, PET plastics are here to stay as it is a behavioural tendency to rely on them.
On the other hand, incorrect disposal leads to PET microplastics leaching into the soil, negatively affecting plastic growth [7]. Most of the received microplastics can be retained by terrestrial soil and freshwater acting as sinks. According to several studies, plastic inputs' proximity and volume cause terrestrial and freshwater habitats to accumulate microplastics in more significant quantities than oceanic ones. An important source of microplastics retained in the soil, transferred by runoff horizontally to rivers, and transported vertically to groundwater aquifers may be the application of sewage sludge to agricultural lands. Processes like bioturbation, which transports particles from the soil's surface to its deeper layers, aid in retention inside the soil. Soil microplastics impact the soil ecosystem because they may transport various contaminants to the soil biota and eventually disrupt the growth and reproduction of soil-dwelling species. Microplastics may also be transported between the strata through soil microbial movement. Because of greater permeability and lower overland flow than urban land, agricultural and forest soils are more able to hold plastic litter than urban land [8].
Microplastics adversely impact growth, reproduction, and survival rates across the food chain in aquatic environments. Larger animals consume less natural prey because of them, and because they are predators, they are vulnerable to the detrimental effects of microplastics. It was discovered that marine species prefer prey smaller than microplastics, yet some fed more on the microparticles than on natural prey, while others mistook them for prey or consumed them while filtering. According to studies on mussels from the Norwegian coast, each one contained an average of 1.5 microplastics or 0.97 MPs per gram [9].
There are three main ways in which PET is recycled
Chemical recycling involves methanolysis, hydrolysis, ammonolysis, glycolysis, and aminolysis. Mechanical recycling is through plastic collection, sorting, balling, chipping, and pelleting. Biodegradation is the method we wish to focus on Out of these methods, chemical recycling is known for generating impurities and harmful chemicals that can be corrosive and mechanical recycling poses limited multiple recycling. Therefore, biodegradation seems to be a more suitable solution due to it being eco-friendly, with low energy consumption and its end products TPA and EG, allowing for a circular economy. In the current plastic biodegradation system, the polymer surface forms a biofilm, which is then followed by the secretion of extracellular enzymes for polymer fragmentation into smaller compounds. These smaller compounds are then consumed by microorganisms and processed through cell metabolism to release carbon dioxide and water [10]. Our project tries to introduce a more optimised biodegradation system for disposing of PET plastics, allowing for a circular economy to be employed.
References
1. Geyer, Roland et al. “Production, use, and fate of all plastics ever
made.” Science advances vol. 3,7 e1700782. 19 Jul. 2017,
doi:10.1126/sciadv.1700782
2. A, M. (2022, September 14). IRCTC: revenue generated from Rail Neer
packaged drinking water 2022. Statista.
https://www.statista.com/statistics/1112426/irctc-revenue-generated-from-railneer-packaged-drinking-water/
3. Kye, Homin et al. “Microplastics in water systems: A review of their
impacts on the environment and their potential hazards.” Heliyon vol.
9,3 e14359. 7 Mar. 2023, doi:10.1016/j.heliyon.2023.e14359
4. Lee, Yongjin et al. “Health Effects of Microplastic Exposures:
Current Issues and Perspectives in South Korea.” Yonsei medical journal
vol. 64,5 (2023): 301-308. doi:10.3349/ymj.2023.0048
5. Tamargo, A., Molinero, N., Reinosa, J. J., Alcolea-Rodriguez, V.,
Portela, R., Bañares, M. A., Fernández, J. F., & Moreno-Arribas, M. V.
(2022). PET microplastics affect human gut microbiota communities during
simulated gastrointestinal digestion, first evidence of plausible
polymer biodegradation during human digestion. Scientific Reports,
12(1), 528. https://doi.org/10.1038/s41598-021-04489-w
6. Hirt, Nell, and Mathilde Body-Malapel. “Immunotoxicity and intestinal
effects of nano- and microplastics: a review of the literature.”
Particle and fibre toxicology vol. 17,1 57. 12 Nov. 2020,
doi:10.1186/s12989-020-00387-7
7. Pignattelli, S., Broccoli, A., Piccardo, M., Terlizzi, A., & Renzi,
M. (2021). Effects of polyethylene terephthalate (PET) microplastics and
acid rain on physiology and growth of Lepidium sativum. Environmental
pollution (Barking, Essex : 1987), 282, 116997.
https://doi.org/10.1016/j.envpol.2021.116997
8. Raza, Maimoona et al. “Microplastics in soil and freshwater:
Understanding sources, distribution, potential impacts, and regulations
for management.” Science progress vol. 105,3 (2022): 368504221126676.
doi:10.1177/00368504221126676
9. Usman, Sunusi et al. “Microplastics Pollution as an Invisible
Potential Threat to Food Safety and Security, Policy Challenges and the
Way Forward.” International journal of environmental research and public
health vol. 17,24 9591. 21 Dec. 2020, doi:10.3390/ijerph17249591
10. Jyoti Singh Jadaun, Shilpi Bansal, Ankit Sonthalia, Amit K. Rai,
Sudhir P. Singh, Biodegradation of plastics for sustainable environment,
Bioresource Technology, Volume 347, 2022, 126697, ISSN 0960-8524,
https://doi.org/10.1016/j.biortech.2022.126697.
