Environment Health News

Bioplastic: Solutions for Global Warming

Close to me one of the biggest offenses of present time is public littering. For that we do not think of our rubbish as our responsibility is a sign of how much we all need change…

Climate change is universal, and it is not one activity or is there a single factor responsible for it.

However, with some thoughts, I have chosen to orient this first part of this article in the context of Pakistan. For considering recent developments, it seems the best time to speak about it, because this time around… people are actually listening.

Early garbage removal trucks, as we all know, used to be open bodied dump trucks pulled by a team of horses. These became motorized in the early part of the 20th century. Indeed, the first close body trucks with a dumping lever mechanism were introduced in Britain in the 1920’s. These not only eliminated the problem of odors but also ensured the safe transportation of waste to waste disposal sites.

Surprisingly, we are a country so gentle about progress, that for the majority of people in its largest city, citizens still depend on a poor fellow moving house to house on his donkey-ridden old cart, to collect garbage from their doorsteps.

It is of significance to understand this gap because, while in developed countries (and the more developed areas of Pakistan), garbage is conveyed by municipalities to landfills for burial, or for incineration or recycling, the garbage in our city on the other hand is dumped and piled on a side of the road, or into empty plots, or even worse, into drainage channels.

According to recent news, an estimated 13,000 tons of trash is produced every day in Karachi, whereas only 3000 tons is picked for removal to government designated landfills. Whether this incompetence is on the part of lack of tools and resources, or good governance, or discrimination against Sindh, or all or none of these reasons, is open to question.

The then forgotten heaps of waste grow bigger in size, and serve as reservoirs for disease. At best, they are got rid of by setting fire to them where and as they are, in open space.

It is important to note that nearly 90% of this waste is plastic litter.

CELLULOSE BASED BIOPLASTICS AS SOLUTIONS FOR GLOBAL WARMING

Everybody is familiar with plastic. An organic polymer of great molecular mass, having enormous tensile strength, a long shelf life and besides, water resistant! It possesses the attribute of plasticity, indeed, to a degree that its name is also an emphasis on this ability.

Given its wide range of applications, plastic is become the choice for producing virtually anything, from bottles and food wrap to toys, crockery, furniture, automobile parts, etc.

Unfortunately, the same properties that make plastic so multipurpose are also the reasons why they pose a very serious threat to our environment.

Plastics require an organic environment for degradation whereas the earth’s natural environment is mainly inorganic. For this reason, plastic waste keeps accumulating, and the only practical option we have left to eliminate it is incineration.

The process of bringing plastics into existence from crude oil necessarily involves heat emissions, while the burning of plastics in attempt to end them, further adds to thermal pollution of the atmosphere. What is still more important is the emission of greenhouse gases during the process.

Greenhouse gases like carbon dioxide and methane have the ability to trap heat, and form a blanket like covering over the planet, so gradually raising the temperature of the earth.

One way, to deal with this problem, may be to make plastic as biodegradable as possible.

This can be done by introducing natural fillers to synthetic polymer chains. The natural filler is mostly of agricultural origin, which is to be plasticized and then compatibilized with the synthetic polymer.

The goal is to produce a polymer blend that is environmentally friendly, that still possesses to a substantial degree all of the useful properties of plastic, and is cheap to manufacture and cost appealing to customers.

Cellulose, which is a structure that is known to make up plant cell walls, is the most abundant renewable biopolymer in the world. On average, cellulose accounts for 50% of the dry weight of plant biomass.

It can be derived from leaves, stems, and stalks of plants and from other sources like corn fiber, corn Stover, sugarcane bagasse, rice straw, rice hulls, woody crops, and forest residues.

Besides this, cellulose can also be rescued from waste created in industrial and agricultural processes such as citrus peel waste, coconut biomass, sawdust, paper pulp, municipal cellulosic solid waste, and paper mill sludge.

Therefore, it should be in the economic interest of a country to utilize cellulose in the making of greener plastics.

At the same time, it is critical to consider the type of plastic used in making the blend.

Certain types of plastics such as polyethylene and polypropylene have a relatively lower global warming impact, whereas some other types like polystyrene and polycarbonate have a higher global warming impact.

Cellulose based polymer blends will be more water soluble and more subject to degradation because of the hydrophilic nature of cellulose. They will not, however, cause the plastic to break down completely.

With time and the increase in demand for more materials by an ever growing world population, oil reserves continue to diminish and will soon completely perish unless we do something about it today.

This makes the need for employing renewable resources as our alternatives even more real.

Nevertheless, one cannot overlook the fact that biodegradable plastics still add to the carbon footprint as carbon dioxide will be released during microbial degradation of cellulose.

Therefore, in conclusion, bioplastics could be one way to reduce global warming, but whether they are the most feasible option for a developing country like Pakistan is debatable. For the reason that environmental problems are very complex and often what may seem like a good idea from an environmental point of view may not be the best alternative from an economical point of view.

In an era where the world production of plastic is increasing tremendously every year, (311 million metric tons, in just 2014) to be sure the simplest strategy to combat global warming at a personal level includes the 3 R’s: Reduce, Reuse, and Recycle.

References:

  • Klar, M., Gunnarsson, D., Prevodnik, A., Hedfors, C., & Dahl, U. (2014). Everything you (don’t) want to know about plastics.Swedish Society for Nature Conservation.
  • Gervet, B. (2007). The use of crude oil in plastic making contributes to global warming.Renewable Energy Research Group, Division of Architecture and Infrastructure, Luleå University of Technology, SE-97187 Luleå, Sweden. www. ltu. se/cms_fs/1.5035.
  • Rowell, R. M., Sanadi, A. R., Caulfield, D. F., & Jacobson, R. E. (1997). Utilization of natural fibers in plastic composites: problems and opportunities. Lignocellulosic-plastic composites, 23-51.
  • Obasi, H. C., Igwe, I. O., & Madufor, I. C. (2013). Effect of soil burial on tensile properties of polypropylene/plasticized cassava starch blends. Advances in Materials Science and Engineering,2013.
  • Sadhu, S., & Maiti, T. K. (2013). Cellulase production by bacteria: a review. British Microbiology Research Journal,3(3), 235.

 

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Duaa Ahmad Abbasi