Why Plastics Have to Be Separated for Recycling

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You are undoubtedly familiar with numbered plastics. If your local community recycles, you probably sort plastics by number. Certain numbers go in your recycling bin while the rest go in the trash. The numbers essentially tell you which plastics your trash hauler can recycle. But they tell your trash hauler something completely different. It all boils down to separating materials.

All the recyclables picked up at curbside – glass, paper, cardboard, and plastic – have to be taken to a sorting center. There, each type of material has to be separated from the rest. Trash must be sorted out as well. When it comes to plastic, sorting facilities are interested in those numbers. The numbers tell them what kind of plastic they are dealing with.

Six Main Types of Plastic

Seraphim Plastics, a Tennessee company that buys and sells industrial scrap plastic in seven states, says that the plastic numbering system utilizes numbers 1 through 7. There are six main types of plastic covered by the first six numbers. Any plastics not classified as one of the six is numbered with a 7 – more or less a catch-all for everything else.

It should be noted that each type of plastic has its own properties and characteristics determined largely by its additives. One type of plastic might have additives designed to make it more flexible. Another might contain additives that make it more rigid.

Additives are that which make plastics different in terms of their application and use. They are what make PET water bottles soft and pliable and plastic pallets strong enough to hold tons of weight. Additives are also what force recyclers to separate plastics by number.

Mixing Is Not Good

When Seraphim picks up a load of scrap plastic from a customer, the plastic is already sorted and cleaned. They might pick up a load of pallets from one customer and a load of plastic totes from another. Even when customers have different types of plastic to sell, they sort it before Seraphim comes for pickup.

From Seraphim’s perspective, mixing is not good. They do not want to send multiple types of plastic through the same grinding process because they don’t want the end product to be mixed. Each recycled product they sell to manufacturers has to be a certain type of plastic.

If plastics were not sorted, manufacturers couldn’t buy the regrind. Why? Because mixing several types of plastics together reduces the quality and the integrity of any finished product made with them. Just like oil and water don’t mix, neither do different types of plastics.

Sorting Affects Recycling Cost

Understanding why sorting is so important might help you understand why the need to sort affects recycling cost. Seraphim can do what it does fairly cheaply because of two things: they only deal in certain types of industrial scrap plastic and that plastic comes to them already sorted. Combined, these two things eliminate costly manual labor.

On the other hand, you have curbside recycling. Plastics have to be sorted from paper and glass. Furthermore, a trash hauler capable of recycling more than one type of plastic still has to separate those types. The more sorting required, the more money it costs to recycle.

Plastics must be sorted for the simple fact that they cannot be mixed by manufacturers who purchase recycled materials. It is no more complicated than that. Unfortunately, what appears to be a quite simple problem is actually prohibitive to recycling due to the cost. If we could find a way to eliminate the need to sort, curbside recycling might actually be profitable.

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