CIRCULAR ECONOMY AND PLASTIC RECYCLING - 2021

Introduction.    

    The population of the world is estimated to be 9.8 billion by the year 2050. Worldwide, waste generated per person per day averages 0.74 kilogram but ranges widely, from 0.11 to 4.54 kilograms . Maintaining the same rate of waste generation in 2050, the total waste generated would amount to a staggering 7.9 million tons per day. Considering the waste generated, Planet Earth will little place left for human inhabitation. Further, the chances of the discarded waste entering the human food chain is already staring at us. In such a situation, maintaining a circular economy is the need of the hour. 

    Circular economy or circularity is an economic system aimed at reducing waste and the continual use of resources. A circular system employs various means to create a closed loop system, minimising the use of resource inputs and creation of waste, pollution, and carbon emission .
    
    Solid Municipal Waste comprises of various material like paper, glass, organic, plastic etc. Further, the proportion of such fractions various from low-income areas to high income areas. Typically, low-income areas have a high fraction of organic waste whereas high income areas have a high component plastic waste. 
    
    Organic waste can be disposed relatively easily as it can be composted under controlled conditions or, if not mixed with other wastes will decompose on its own. Other waste however must be recycled, through varied processes which uses energy and water amongst other resources. Recycling methods therefore need to be examined thoroughly prior implementation. Notwithstanding the need for energy/ water in recycling processes, use of virgin material damages the eco system and therefore there are good arguments in favour of reduction in use of such virgin material.
    
    To examine the factors pertaining to plastic production and plastic waste affecting implementation of a circular economy let us compare the various aspects.

Production

    The production of plastics involves multiple steps which use resources from the environment.  Plastics are derived from natural, organic materials such as cellulose, coal, natural gas, salt and of course, crude oil. Heavy crude oil is distilled in a refinery to separate it into lighter groups of lighter components called fractions. These fractions are a mixture of hydrocarbon chains differing in terms of size and structure of their molecules. The fractions are processed and made into Plastic. The whole process consumes not only crude oil, which is a limited natural resource but also large amount of energy generation of which also consumes natural resources like fuel and gas. It is therefore apparent that production of virgin plastic consumes large amounts of natural resources.

    The Plast India Foundation Report of 2018 states that the annual production of virgin plastic in India in 2016-17 was 14,088 Kilo Tons and projected production for 2019-20 is about 15,500 Kilo Tons  (Which translates to about 15.5 million tons). 
    
    As per a report by IndiaSpend  dated 05 Oct 2020 around 43% of manufactured plastic in India is used for packaging purposes and is mostly single-use plastic. The total plastic waste generated during the year 2018-19 as reported by the Central Pollution Control Board in its Annual Report  is 33,60,043 metric tons per annum.

Waste Generation

The world generates 2.01 billion tonnes of municipal solid waste annually. Worldwide, waste generated per person per day averages 0.74 kilogram but ranges widely, from 0.11 to 4.54 kilograms. High Income Countries generate about 34 % of the total world waste though they comprise only about 16% of the population . 
    
    From Table 1  it is evident that while the percentage of organic and paper/ cardboard waste varies from region to region, the quantum of plastic waste as a percentage of total waste remains largely the same. 
A comparison based on income levels of countries  reveals a similar picture in so far as plastic waste is concerned. (Table 2)

Linear Economy Vs Circular Economy

Recycling Plastic Waste and Circular Economy

    Plastic waste can be managed through several different methodologies. Currently a large part of plastic waste is either incinerated or is littered / ends up in the environment. 

    Management of plastic waste can be best undertaken by reducing use and re-using. However, since not all plastics can be re-used at commercially viable   plastic waste management the general ways practiced are reduce, reuse, and recycle. 

    Recycling plastic can be broadly divided into four main classifications.  Primary or re-extrusion, Secondary or mechanical based, Tertiary, or chemically oriented, and quaternary or energy recovery. 

Primary recycling (re-extrusion) – This involves the re-introduction of clean scrap plastic in the manufacturing process. This method is usually difficult as clean single type plastic waste is not easily available. 

Secondary recycling or Mechanical Re-cycling involves collection, cutting/shredding, cleaning, milling, washing, and drying followed by extrusion. The plastic so recovered is usually used in manufacture of products requiring fewer pressing attributes, in comparison with original material usage. 

Tertiary recycling also referred to as Chemical or Thermo chemical recycling involves using the waste plastic as feedstock in processes that generate fuel and chemicals. Segregation of plastics is not as essential in undertaking these methods. 

Quaternary Methods may be described as methods of plastic waste disposal for energy recovery. Additionally, waste plastic is also increasingly being used as a mixture in bitumen road building as well as for co-processing in cement kilns.

Conclusion

Plastics have become an integral part of everyday life and while it may not be possible to live without plastics, there is a case for reduction in its use, especially single use plastic which as discussed have a short life span, are difficult to recover and usually end up as litter. 

Though, technology to sort waste into main streams of polypropylene (PP), high?density polyethylene (HDPE), low?density polyethylene (LDPE), PET and polystyrene (PS) using a series of rotary screen drums, near?infrared sorting and washing steps is available and can help in conversion of different types of plastic to their resins, the same is not a preferred method due commercial viability.  Additional research must be carried out to devise methods to convert waste plastic into resins which can be re-used as virgin material.

Development of suitable environmentally friendly procedures for conversion of waste plastic into resin for use in virgin plastics are the need of the hour and must be pursued actively. 

Packaging materials which comprise a very large portion of the plastic manufactured and have some of the shortest life spa should be made recycle friendly, or other materials developed for replacing such packaging material.

Return of packaging by end users must be encouraged and manufacturers must explore methods for re-use of such recovered material. 

A better integration and collaboration of all stakeholders along the value?chain combined with a forward?looking investment strategy, standardization, and legislation are recommended. Penalties or high rates of taxes for CO2 emission and suitable measures to integrate environmental costs, are essential to ensure market interest and faster adoption of efficient recycling methods. Further, stringent packaging design regulations to dictate full recyclability and strong regulations on waste disposal would pave the way towards a circular economy.

The figure below clearly depicts a truly circular plastic economy

Author: Satyendra Vaidya

Email: satyendravaidya@hotmail.com