How to Dispose Large Quantity of Plastic Waste?
We have been in business of plastic waste disposal since year 2006. We work with lot of companies for disposal of large quantities (1,000kg to 30,000 kilograms per day) of plastic waste. Some of these companies need to dispose plastic waste as a one-time activity and many of these companies need to dispose plastic waste on daily basis. Given below is a strategic approach that needs to be taken for the most effective method of disposal of plastic waste. Most of the time asking right questions can lead to the most effective method of plastic waste disposal.
- Analyse the situation that is generating the plastic waste:
a. What is the plastic recycling code mentioned on the plastic waste? What quantity of plastic waste needs to be disposed? What is the location of plastic waste generation point? What are the physical properties of this plastic waste including bulk density & moisture content? Does this plastic waste contain any type of chemicals or hazardous materials?
These series of questions gets us the information necessary to calculate the transportation cost of the plastic waste once the suitable disposal facility is identified. The source of generation of plastic waste is very important to be understood. If the plastic waste is generated from hospitals then this plastic waste is categorized into Biomedical Waste and can be only disposed in by medical waste incinerators. If the plastic waste contains chemicals or hazardous materials then detailed analysis report and material safety data sheet (MSDS) of such plastic waste is required before deciding the further course of action.
b. Is the plastic waste segregation at source? Is the plastic waste quality good enough to be recycled physically? Is it only one type of plastic waste or it is a mixed plastic waste? Is it a multi layered plastic waste?
It is necessary to understand of the plastic waste is segregated at source into PE (polyethylene), PP (polypropylene), PET (Polyethylene terephthalate), HDPE (high density polyethylene), LDPE (low density polyethylene) etc. Completely automated optical sorting machines are available that can segregate different types of plastic waste from a mixture.
If the plastic waste it segregated at source chances are very high that this plastic waste can be sold for recyclers. the number of plastic recycling Industries around every City that take pure and segregated type of plastic waste for remoulding and conversion into plastic granules. These plastic granules and be used for manufacturing new articles or objects of plastic (like carrey bags, plastic objects containers, packing materials etc). For recycling to be possible, plastic waste generated needs to be of (i) a single type of plastic as well as (ii) the quality of plastic is very good (Polymer content of more than 95% and very low content of moisture dust or fillers).
c. How frequently is this quantity of plastic waste generated?
Plastic waste needs to be disposed of only one time then it is quite easy mostly. However, if this quantity of plastic waste is generated only for weekly or monthly basis the cost of plastic waste disposal can very quickly rise to big number.
- Selecting the appropriate recycling method based on the quality and type of plastic.
There are three methods for recycling or disposal of plastic waste:
a. Physical Recycling
Physical recycling involves changing the shape of plastic waste to convert it into some other objects of plastic. Physical recycling of plastic waste is the most commonly used method of plastic recycling. Most of the plastic recycling businesses use physical recycling techniques for recycling of waste plastics.
In case of physical recycling the plastic waste is melted using plastic extruder. Then plastic is passed through a fine mesh to separate dirt and foreign matters. Then plastic is extruded through 5 mm holes to convert it into strings. These strings are cooled down by immersing into water. After cooling these wires are cut into smaller pallets for recycling. Plastic pallets manufactured from recycled plastic are used as it is for manufacturing new plastic or it is used in mixture with fresh plastic granules to make plastic objects.
Key challenges of plastic waste disposal using physical recycling:
Physical recycling of plastic waste requires the plastic waste to be segregated into different types of polymer. Mix plastic waste cannot go for physical recycling because by the time one plastic becomes semi solid in the excluder the other type of plastic may start flowing by complete melting into liquid. It is estimated that less than 10% of plastic waste generated is suitable for physical recycling. Even the physical recycling of plastic waste is the most commonly available technology for plastic waste disposal, less than 10% of plastic waste can be disposed using physical method of recycling. Plastic waste like multi their plastic, laminates, plastic waste with aluminium foil, Single use plastic packaging waste cannot be disposed using physical method of recycling.
Advantages of physical methods of recycling for plastic waste disposal:
- Low capital investment in the technology
- The finished product is plastic granules that can be used for manufacturing new products of plastic
Limitations of physical methods of recycling for plastic waste disposal:
- Not all types of plastic wastes are suitable for physical method of recycling
- Where is few types of plastic waste can be recycled using physical method of recycling
b. Chemical Recycling:
Plastics are manufactured from crude oil or natural gas. Chemical recycling of plastic waste involves heating plastic to temperature is between 300°C to 400°C at which the waste plastic molecules chemically decompose into crude oil. This crude while is further heated to temperatures of 450°C to convert it into mixture of petrol, diesel and kerosene. Hydrocarbon gas and carbon black powder produced as a byproduct of this process. This process of chemical recycling of plastic waste is called pyrolysis. The industry that converts waste plastic into pyrolysis oil is called Pyrolysis Plant. Agile Process Chemicals LLP is one of the leading organisation that provides machinery and technology for chemical recycling.
In chemical recycling of plastic waste the plastic is not burned but it is chemically broken down into fuels and petrochemicals. The fuel oil mixture of petrol, diesel and kerosene obtained from plastic waste is then subjected to fractional distillation two separate petrol, diesel and kerosene from each other.
Chemical recycling of plastic waste is suitable method for disposal of all types of plastic waste. Even the plastics that cannot be recycled physically can be recycled chemically through process of paralysis. Another type of chemical recycling of plastic waste is hydrolysis however this process of hydrolysis requires extremely pure plastic waste for the process to be successful and produce high-value products.
Currently negligible quantity is of plastic waste generated is recycled using the chemical method of plastic recycling. Using chemical recycling of plastic waste fuels and petrochemicals can be produced from waste plastic. Plastic waste disposal using chemical recycling is the requirement of crude oil excavation. Production of US and petrochemicals from waste plastic has smaller footprint compared to the production of fuels and petrochemicals from crude oil.
Advantages of plastic waste disposal using chemical method of recycling:
- Any type of plastic waste can be recycled
- There is no of combustion plastic waste in this process
- Plastic waste can be converted into petrochemicals like petrol, diesel, kerosene and base oil
- Even the plastic waste that cannot be disposed using physical methods of recycling can be disposed using chemical methods of recycling
- The byproduct hydrocarbon gas produced during the process is used as a fuel for process to continue
- This process takes place in absence of oxygen and therefore there is no production of hazardous pollution unlike incineration
- Does not require segregation of one type of plastic waste from the other type
Key challenges of plastic waste disposal using Chemical recycling:
One of the key challenges in plastic waste disposal using chemical recycling is that the production cost of fuels produced out of this process is equivalent to the cost of crude oil derived fuels. Even the mixture of plastic waste suitable for disposal using chemical recycling, plastic needs to be segregated from foreign materials like stones, metal et cetera that can damage the Pyrolysis reactor. Municipal solid waste segregated plastic waste contains high quantities of moisture and dirt and this makes the pyrolysis oil production cost equal to the selling cost of this fuel.
c. Burning Or Incineration
Burning or incineration are the least desirable and the most environmentally harmful methods of plastic waste disposal. Open burning of plastic waste generates harmful air-pollution which includes high quantities of suspended particulate matter, dioxin, furans and volatile organic matters.
In incineration method plastic waste disposal, the plastic waste is burned, and the heat is used for production of steam. The steam produced is used for producing electricity. During the compression of plastic waste, the harmful chemicals like dioxins and furans are produced. Many countries have banned incineration of plastic waste due to the harmful due to the harmful environmental impact of this process.
Biomedical waste containing plastic waste is the only suitable candidate for disposal using incineration. Incineration destroys the harmful bacteria and viruses present in the biomedical waste. Apart from incineration of biomedical waste this process of plastic waste disposal is not recommended for disposal of any other type of plastic waste.