Smart Management of Plastic Garbage

Captain Arif Mahmud

The government banned polythene bags using the Bangladesh Environment Conservation Act 1995.  Bangladesh was the first country to ban plastic bags and over a decade many developed countries are still struggling to emulate this success.  Although plastic bags make up only a small percentage of all litter, the impact of these bags is significant along with other plastic garbage materials.

Under the law, there is a complete ban on production, import, marketing, sales, display, storing, distribution, transportation and use of polythene of less than 55 micron thickness for business purposes. The Bangladesh government in 2010 enacted another law, titled the ‘Mandatory Jute Packaging Act 2010’ for the compulsory use of jute in packaging products instead of plastic materials.  Plastic bags are harmful in many ways. The used bags eventually find their ways into drains, canals, rivers, parks, streets causing pollution to the environment.

One of the major impacts of plastic bags in Bangladesh is the effect on the water drainage system.  Bangladesh has an annual rainfall of up to 5 meters and holds the world record for the highest rainfall in a period of a single day. Arranging sufficient drainage infrastructure is a major challenge for the Government of Bangladesh and urban flooding is common in this country. Plastic bags clog drains and waterways, threatening urban environments and creating many health issues. Drainage systems blocked by plastic bags have been identified as a major cause of flooding in Bangladesh during monsoon season. Following the 1998 flood it was estimated that up to 80% of the city’s waterlogging was caused by polyethylene blocking the drainage system.

The technical name of the thin plastic bag is Low-Density Polyethylene (LDPE). Apart from plastic bags there are various plastic products that generates huge amount of plastic garbage. For example the mineral water bottles or the carbonated drink bottles are made of Polyethylene Terephthalate (PETE or PET), the more durable plastic bottles such as shampoo or washing liquid is made from High Density Polyethylene (HDPE), the piping materials are normally made from Polyvinyl Chloride (PVC), the food packing materials are made from Polystyrene or Styrofoam (PS) Some hard plastic containers and objects are made from polypropylene (PP).  Added to the plastic bags all the above materials generate huge amount of plastic garbage and pollute our environment including canals, rivers, seas and oceans. The floating and submerged plastic garbage are causing harm to the sea birds and various aquatic animals. The oceans are also getting infested with various types of plastic garbage discarded by human beings.

Three major areas of Bangladesh, such as Dhaka, Chittagong, and Sylhet, are in great danger. It is estimated that about 14 million pieces of poly-bags are being thrown out every day in Dhaka city. A report has stated that Bangladesh experienced floods in urban areas in 1998 and 2008 where polythene and plastic materials were one of the major causes for the blockage of the drainage systems. A recent report published by Earth Day Network (2018) ranked Bangladesh 10th out of the top 20 plastic polluting countries in the world. Plastic contributes eight percent of the country’s waste, which is equivalent to 800,000 tones, of which around 200,000 tones go into the ocean and rivers. Bangladesh has a great opportunity to reuse its plastic wastes to foster both of economy and protect the environment from pollution.

Water pollution by plastic garbage in Bangladesh (Image source: The Internet)

Alternate Use of Plastic Garbage:

People are prone to use plastic bags, bottles and packaging materials as these products are easily available, cheap and light weight. Presently cities are overflowing with plastic garbage and the conditions of towns and villages are getting worse. In some cities there are garbage collection facility but that does not normally cover the whole city. The collection and the dispose system is not very efficient. Normally there are no such garbage collection facility in small towns and villages. Most of the plastic garbage are found in abundance on streets, roads, fields but ultimately some of these are deposited in water polluting rivers and oceans. Even if there is a good collection system and most of the garbage are collected and stored in some place then after few years more and more of land area will be required to establish garbage dumping grounds. So we must try to find out the smart use of all the plastic garbage. A wide range of products can be generated from plastic garbage.

Garments and shoes from recycled PET bottles

Recycled polyester yarn manufacturing is very easy and economical which are encouraging fabric manufacturers. Sorted and graded plastic bottles are chopped and shredded into small bits that melt and soften with heat. Molten plastics passes through a number of tiny holes which results in thin filaments.

These filaments are used nowadays into both woven and knit industry to manufacture fabric. Running shoes, soft shoes, other sports gears like the shorts, vest, jogging suit, sweater, pull over and normal clothing items like T shirt, polo shirt, hoodie, denim and jeans trousers, shirts , ladies dress , bags and fleece jackets can be manufactured from these recycled polyester yarn.

Construction of Roads with Plastic waste:

The waste plastic is processed, granulated and combined with regular asphalt for use in road construction and surfacing to extend and enhance the binding properties of the bitumen. All kinds of plastic garbage including the normal plastic shopping bags (Low-Density Polyethylene LDPE), PET bottles, plastic packing materials can be used in the road building process. Experts estimate that these types of roads will be 60 percent stronger than regular asphalt roads and last around 10 times longer when compared with normal asphalt roads. Plastic roads are cheaper, ecofriendly and if built with correct techniques may last more than 50 years.

Roof, Garden, Pavement, Footpath and Car parking area tiles from Plastic waste:

All types of plastic garbage can be used to produce different grades of tiles that may be used on roof, footpath, pavement, car parking and in garden.  Plastic garbage is collected and shredded into small pieces mixed with sand or crushed stone powder and desirable color, this mixture is heated and the molten material is passed through hydraulic press to give the shape of the required tiles for pavement, garden, footpath, and pavement and also for roof. All these tiles can be of various color as per the demand of customer. These type of tiles are very durable and they can last for more than fifty years.  Most of them are heavy duty and will not break under heavy load. These tiles are fire and heat resistant.

Furniture from Plastic Garbage:

Plastic bags, bottles, packing materials and virtually all types of garbage may be used to manufacture durable plastic furniture. The plastic garbage is collected, cleaned, washed and cut into small pieces. These small pieces are heated and the molten mixture can be used to construct various types of plastic furniture.  Many European countries are also using 3D printers with molten plastic to construct furniture with aesthetic designs.

Fuel oil and diesel oil can be manufactured from Plastic Garbage:

Plastic can be burnt at high temperature (450 degree Celsius) with an added catalyst (Fly ash) in the absence of Oxygen. This is called Pyrolysis. By this way the plastic can be converted in to 80% Oil, 15 % Flammable Gas and 5% Carbon Black. The oils that may be generated by pyrolysis are Naphtha/light oil, Low Sulphur Heavy fuel oil, Base oil and paraffin wax. It may be possible to produce diesel oil from Low Sulphur Heavy oil by distillation and purification.

At least four types of flammable gas may be derived from pyrolysis and they are Hydrogen, Methane, Ethane and Butane. Hydrogen can be used in industries, other gases can be used as fuel for industrial or domestic purpose.

The Carbon Black is commonly used in the production of vehicle tire to absorb heat. It is also used in photocopier, printing machines and also for making colors.

Author is an Assistant Professor , Maritime Science Department, Bangabandhu Sheikh Mujibur Rahman Maritime University, Dhaka, Bangladesh.


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