Plastics have been universally reviled as one of the scourges of our time, a result of our increasingly consumerist lifestyles. The recognition of their toxicity when left to degrade in the environment has now been overstated. Yet we continue to manufacture virgin plastic, derived from crude oil mined from the earth, and we continue to dump single use and other end of life plastic products into our landfills, fields, and water bodies, including 8 million tonnes a year into our oceans! The increasing need to recycle plastics is also being recognized however, and global recycling rates have steadily increased over the last few decades.
Chennai has a robust plastic recycling ecosystem, hugely supported by the informal sector that we have continuously championed over the last year. Waste pickers source plastic from landfills, curbside bins and unauthorized dumps, and sell to Kabadiwallas who themselves source enormous quantities from their vast network of households, commercial enterprises and institutions. A complex system of categorisation based on local nomenclature is what drives the first levels of this industry, but which remains largely unknown to the public. There is also a universal system of labeling known as the ATSM Resin Identification Code, that is embossed onto the bottom of most consumer plastic products. In this post, we will shed some light on the types of plastics that make your everyday goods, as well as the local nomenclature and its role in the recycling ecosystem.
Resin Identification Code
It is not merely the triangle with three arrows that indicates a product is recyclable, rather the number in the middle of the symbol that tells you exactly what polymer type the product is made from. It was originally developed by the Society for Plastics Industries (SPI) in 1988 to help workers at Materials Recovery Facilities segregate plastics more efficiently. The administration of the RIC is now under the ATSM. Below are the 7 types of plastics, classified according to the Resin Identification Code (RIC), usually embossed onto the bottom of the product, represented by three arrows forming a triangle, and one of the 7 numbers in the middle.
- PET (Polyethylene Terephthalate) - One of the most widely used and recycled polymers, most water and soft drink bottles, mouthwash bottles, peanut butter jars and some take out food containers, are made from PET. It is intended for single use, and repeated use increases the risk of leaching carcinogens. It is recycled into polyester fibre for fabrics such as fleece, PET strap, and even new PET bottles.
- High Density Polyethylene (HDPE) - A stiff and hard-wearing plastic, HDPE is used to make most of your shampoo, detergent and motor oil bottles. It is the most commonly recycled plastic and is relatively safe. Because of its strength and resistance to high temperatures, it is recycled to make plastic lumber, plastic tables and chairs, and other products that require durability.
- PolyVinylChloride (PVC) - Known as the ‘poison plastic’ because of its toxicity, it is well known for its use in the ubiquitous, grey plumbing pipes. It is also used to make shower curtains, folders, the sheathing for computer cables and surprisingly, even teething toys for children! Only a very small percentage of PVC is recycled and it should be avoided at all costs.
- Low Density Polyethylene (LDPE) - Lower in density than HDPE, it is also very widely used and recycled. It is used to make most plastic bags, bread packets, and squeezable bottles. It is relatively safe and should be recycled as far as possible.
- Polypropylene (PP) - All the tubs used to package food products such as yoghurt, ice cream, take away sweet boxes, vegetable trays, bins, and some toys, are made from PP. While previously not widely recycled, it has increasingly become so today and more recyclers are sourcing scrap PP. It is very resistant to high temperatures and hence its use in food packaging. It is recycled into a number of products like bins, trays, brooms and landscape stripping.
- Polystyrene (PS) - Commonly known as styrofoam, it is widely used to make foam drinking cups, take-out ‘clamshell’ food containers, egg cartons, and packaging ‘peanuts’ used to provide padding for goods when packaged for transport. It is structurally weak and breaks up easily. For this reason it can be found polluting beaches and water bodies across the world. It can also leach styrene, a carcinogen, into the food that it is used to package. Although it is recycled (mostly industrial grades such as High-Impact Polystyrene and Acrylonitrile Butadiene Styrene), the market is very small and styrene products should be avoided.
- Others - Anything labelled with a number ‘7’ is either a polycarbonate (a combination of two or more polymers, or one of many other miscellaneous thermoset plastics like nylon, epoxy etc. This is the most problematic category as there is no way for the recycler to tell what material the product is made from.Furthermore, most of the polymers found in this category have a chemical structure that makes them difficult to recycle. Number ‘7’ should be avoided at all costs!
Local terminology and recycling
Kabadiwalla Connect has just opened its own Materials Recovery Facility at Madhavaram, where we source plastics from Kabadiwallas through our app. The plastic is segregated according to grade and colour, shredded into flakes, and sold to reprocessors. We have labourers who have been in the recycling industry for 30 years, and whose expertise in identifying and segregating plastics is unparalleled. Spending time with them and watching them work has given us insights into the local system of plastic recycling.
Kabadiwallas broadly refer to all rigid, non PET, and non PP plastic items as ‘bommai’. Thinner plastics are referred to as ‘karuppu’. Along with PET bottles, these are collected together in an unsegregated assortment of grades and colours and sold to middle aggregators. It is here that most of the segregation takes place. A whopping 58 categories of plastics have been recorded at middle-men warehouses!
Local terminology is governed mostly by the type of product, and then by colour or appearance. Bommai for example, consists of mostly HDPE items divided into blue, red, green, yellow, orange and white categories. ‘Ujala’ is another category used to separate all dark blue detergent bottles. Similarly the most common PP products such as take away food containers, sweet boxes, yoghurt and ice cream tubs, are separated into several colours under ‘PP’. ‘Natural’ PP is another high-demand category which includes all transparent PP products. PET bottles are the most easily identifiable and are segregated as ‘PET’, but their caps however are made of PP, and are tossed into the PP piles according to colour.
Fascinatingly, there are several other categories like ‘Bucketi’ which consists exclusively of buckets and dust pans, further divided into colours. Anything with a shiny, like-new appearance gets a ‘super’ prefixed to it and is separated, and anything dirty or dull gets a ‘dull’ prefixed to it and is thrown into its own pile. ‘Sonala’ is used to describe thin, colourless, translucent plastics with a cloudy appearance. Items in this category include the saline bottles used for drips, some types of hard brushes used for washing clothes, some cans, and the caps from bubble top containers. ‘Kodam’ is used exclusively for broom handles, and ‘Trays’ (vegetable and drink), ‘Cans’ (jerry cans) and ‘Brush PP’ (toothbrushes) each get their own category. All items, which either do not fit into any category, are unidentifiable, or are of a colour too distinct from the common ones, are segregated separately and classified as ‘Mati PP’.
The separation of scrap into so many different categories is a benefit as well as a bane to recycling. As you can see, ultimately there are 4 main resins (PET, HDPE, LDPE, PP) making up the majority of post-consumer scrap, but which are divided into over 55 categories when they reach middle-men godowns. Processors currently want flakes separated into these categories so they can make pellets without having to colour sort, and thus the nomenclature has long been entrenched in the recycling ecosystem. The problem is, we do not yet have the technology available abroad such as Near Infrared Optical Sorting, which can automatically detect resin type and colour, and segregate the plastics accordingly.
At our godown we are trying to streamline the entire process and create a logical, efficient system of segregation to best facilitate reprocessing of scrap plastic.
If you want to know more about our operations, contact us at email@example.com.
-Written by Farhaad Khazvini