Introduction

The increment in urbanization, population, and industrialization have resulted in a high concentration of plastic waste production as plastic has been a significant part of lives. Some of the major problem caused by plastic waste is choking of drains, leaching on the ground and land water, infertile land, environmental hazards caused by burning indiscriminate, etc. Littering is a significant environmental issue; it gives an ugly look to a place. In numerous urban areas, the administration faces difficulties in handling plastic waste due to improper waste management. Monitoring of waste material from beginning to disposal is waste management. It consists of the collection, transportation, processing, and finally disposal. Waste management aims to provide hygienic living conditions to decrease the quantity of refuse that arrives and leaves. The figure illustrates technologies adopted for plastic waste management.

Waste Management Hierarchy

In the present fast developing world, the administration of plastic waste is one of the complex operations. It is essential to reduce generated waste apart from recycling or reusing the goods to maintain a sustainable environment. The preferable way of plastic waste management is to follow the waste management hierarchy. The waste hierarchy is divided into source reduction, reuse of products, recycling, resource recovery in terms of energy and material, incineration, and landfill, the least preferable. 

Waste Management Hierarchy

Source Reduction

In waste management strategy hierarchy most ideal step is source reduction as it eliminates the requirement of managing waste (handling, transportation, and disposal). Consuming fewer items and disposing of the waste is considered source reduction. When products are manufactured, clean production technology should also be considered. Waste minimizing strategies like using reusable products, purchasing products with minimum packaging, reading online e-newspaper instead of hardcovers, buying durable material products in bulk that are non-hazardous, and consuming recycling products are a few of the strategies for waste minimization. Source reduction helps preserve natural resources by manufacturing durable products and reducing waste as equivalent to recycling, incineration, or landfilling. 

Reuse

Reuse is when a product or a material can be used again for the same or different application without upgrading. Reuse extends the life of the material or a product and is similarly an alternative for source reduction. Some of the examples of reuse are reusing durable cups/mugs, cardboard boxes, refilling bottles, donating material to NGOs like computers and furniture. Reuse is preferable over recycling as the product does not change and no amount of material and energy is used. Also, it reduces cost and time consumption for disposal.

Recycling

Traditional plastic is very durable and does not decompose quickly in the ambient surroundings, so it has remained in the landscape for many years. In a typical environmental condition, polymers need hundreds of years to degrade and decompose. The need for recycling and reducing the use of virgin products should be more than the consumption rate. Low-density polyethylene, high-density polyethylene, and nylon are the primary raw material for plastic products. MSW (municipal solid waste) has a substantial fraction of plastic waste, mainly packaging material and discarded products.

Resource recovery

The plastic industry has effectively acknowledged technologies for recycling and recovering waste from discarded material. Following methods of plastic waste for treatment, recycling, and recovery have resulted from years of research.

• Polymer Blended Bitumen Road

The use of waste polymer in the bituminous concrete mix may aid in minimizing the construction cost of the roads. For building flexible roads, this method is being applied effectively. On average, plastic save 8% of bitumen costs in road construction. 

• Co-processing of Plastic Waste in Cement Kiln

Co-processing uses waste products as alternative fuels or raw materials in industrial operations to recover energy and material. Due to the high temperature in cement kilns, waste can be effectively disposed of without harmful emissions. 

• Plasma Pyrolysis Technology (PPT)

 Plasma pyrolysis technology breaks down organic compounds into gases and non-leachable solid wastes in an oxygen-starved environment. Plasma pyrolysis decomposes substances by utilizing a substantial fraction of electrons, ions, and excited molecules, as well as high-energy radiation.

•  Conversion of Plastics Waste into Liquid Fuel

The polymer degrades to lower molecular fragments. In the process of conversion of waste plastics into fuels, random depolymerization is carried out in an especially designed reactor in the absence of oxygen and the presence of coal and certain catalytic additives. This process has the lowest maintenance and installation cost among many available methods. 

Incineration

Incineration is a typical procedure for treating waste, it provides recovery of energy from waste to produce power, and the process can decrease volume up to 90% and mass by 70%. The fuel consumed to burn the waste is 80% of waste processing cost Rs. 5460/ton, a primary demerit of this technology. Due to high moisture content, it is hard to get the base 0.07 kW/kg calorific estimation of waste required to sustain this technology. Incredibly lethal and cancer-causing agents which are unsafe to human wellbeing are discharged from associated technology like dioxins, furans, mercuric chloride, hydrogen fluoride, hydrogen chloride, and polychlorinated biphenyl (PCBs).

Landfill

Landfilling is a traditional method where the waste is dumped underneath the soil in an isolated site. For the disposal of waste, it is one of the more regularly utilized strategies. It is a well-known technique of waste management as landfilling is a low-cost option. Given the landfill transfer exchange, immense quantities of the developing countries are dumping their waste instead of reusing or recycling or trying different strategies.