Plastics play an important part of our modern lives. Look around and imagine how different life would be if plastics were not available. How many products do you use every day that would be difficult and expensive to make – if not impossible – if they had to be made from some other material.
Recycling plastic is an important way of keeping plastic containers out of our landfills, but it also makes more plastics available to manufacturers who can use recovered plastics in their products. However, recycling plastic is a little more complicated than recycling materials like cardboard, glass, aluminum and steel, which can be ground up or melted down and remolded directly into new products. Plastic takes a little more work — and sometimes quite a bit more technology – to be recovered and made into new products.
According to the EPA, plastics make up more than 12 percent of the municipal solid waste stream, a dramatic increase from 1960, when plastics were less than one percent of the waste stream. The largest category of plastics are found in containers and packaging (e.g., soft drink bottles, lids, shampoo bottles), but they also are found in durable (e.g., appliances, furniture) and nondurable goods (e.g., diapers, trash bags, cups and utensils, medical devices). The recycling rate for different types of plastic varies greatly, resulting in an overall plastics recycling rate of only 8 percent, or 2.4 million tons in 2010. However, the recycling rate for some plastics is much higher, for example in 2010, 28 percent of HDPE bottles and 29 percent of PET bottles and jars were recycled.
Types of plastics use a Resin Identification Code (RIC) which is stamped into the containers, typically on the bottom, to identify what kind of plastic was used to make the container. This system was introduced by SPI, the plastics industry trade association, in 1988. The SPI coding system offered a way for consumers to determine whether or not certain plastics are collected for recycling in their area.
The type of plastic determines what can be done with it and how much processing will be needed.
Markets for Recycled Plastic
Currently, in the USA, the market demand for PET and HDPE (RIC #1 and #2) plastics exceeds the available sources, so most municipalities have a system for collecting and selling these types of plastic to recyclers. But, as of 2010 less than 30% of the available plastics in these classes were being recycled; 70% or more were being tossed into the regular trash and headed for landfills.
Other plastic types are less in demand and more expensive to recycle, so these may not be accepted for recycling by most metropolitan waste management systems (WMS). Most of these plastics ARE recyclable, but the demand is not sufficient for many WMS to dedicate the space and manpower to separating and storing them. At present. That may change as oil prices go up and demand for recycled plastics increase.
PET plastics are cleaned sorted by color and ground into flakes. These flakes may be compressed into recycled PET pellets (RPET). RPET can be melted and injection molded into new containers, formed into sheets and molded into blister packaging, used in making strapping tape, and even injection-molded engineering components and building materials. But the fastest growing use for PET is to melt the pellets and draw the plastic into thread which is woven into fabric much the same as Dacron. These fabrics are too irritating for clothing that will rub against skin, but are commonly used to create strong, durable products, such as jackets, coats, shoes, bags, hats, and accessories.
One attempt to circumvent the problem of waste plastics is the invention of biodegradable plastics. These plastics, which are decomposed by microbes or light, have small amounts of additives, generally about 5 percent cornstarch. However, the speed and environmental conditions in which the plastic will break down has not been determined. The goal is to break plastic down into carbon dioxide and water, but some “biodegradable” plastics merely break into very small pieces rather than changing their chemical make-up. Also, it is not known what really takes place in degradation and if there are any harmful consequences. Unfortunately, degradable plastics cannot be recycled back into the raw material stream.
The next time you’re tempted to toss that water bottle, soda bottle or milk jug into the trash, please reconsider and think of the many useful things that could be made from that container; reducing our demand for new plastics made from petroleum, and reducing the non-biodegradable waste taking up space in our landfills. Please reduce, reuse, recycle!