Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3–4% is expended to provide energy for their manufacture.
A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide.
Plastic recycling is broken up into a few distinct steps. Generally these steps remain the same for most types of recycling facilities, but certain steps can be combined or omitted in some situations
Step 1: Collection
The first step in the recycling process is always collecting the plastic material that is to be recycled.
This step is completely reliant upon businesses, restaurants, and the public to dispose of their plastic waste in the correct place. If plastic waste is disposed of in normal trash bins, it will not be recycled, so it is extremely important to separate common waste and plastic waste.
Step 2: Sorting
After plastics are collected and transported to a recycling facility, the next step is sorting.
Machines sort plastics into different areas based upon a multitude of properties that are often dependent upon the recycling facility or what final product is being produced.
Plastics are usually sorted in a few common ways, such as the type of plastic (material it is made with), color of the plastic, or even how it was made. This is important because different types of plastics must be processed in different ways and some recycling facilities are only capable of recycling one type of plastic. If the wrong type of plastic is processed at the incorrect facility it can reduce the efficiency of the whole process and require the entire batch to be sent back again for resorting
Step 3: Washing
Just like with clothes, fruits/vegetables, and many other things, plastics must be washed before they are further processed. The goal of this step is to remove impurities and everything that is not made from plastic.
Most containers and packages have labels, adhesive, or even food residue that must be removed. This non-plastic waste cannot be recycled and can cause the final product to have poor structural integrity
Step 4: Resizing
Resizing consists of shredding or granulating the plastic waste into small particles. This increases the surface area of the plastic, making it easier to process, reshape, and transport if needed.
Step 5: Identification and separation of plastics
The identification and separation of plastics is when the now small plastic particles are tested to determine their quality and class.
Step 6: Compounding
Compounding is when the small particles are smashed and melted together into plastic pellets