Recycling

Recycling involves the reuse of discarded materials in the manufacture of new products.  This helps prevent waste, reduces the use of new raw materials, lowers energy consumption, cuts down on air and water pollution due to lowered incineration and landfilling, and drops GHG emissions when compared to the production of new items from raw materials.  The main benefit from recycling is reduced landfill costs.  Recycling also lowers a country’s carbon emissions e.g. 49 million metric tonnes was generated in the United States for the year 2005.

The PGSS Environment Committee

After products to be recycled are collected, they are put on a conveyor belt.  Some areas demand that you separate paper from other recyclables, while others allow you to mix the two together.  In the latter case, large sized portions of cardboard and plastic bags are removed manually.  Automated machinery separates recyclates by weight.  Paper and plastic are separated from glass and metal.  A spectroscopic scanner can determine between different types of paper and plastic.  This is based on the different wavelengths absorbed by the differing materials.  Magnets can be utilized to separate metals such as iron, steel, and tin cans.  Aluminum cans are removed via the use of magnetic eddy currents which detect non-ferrous metals.  Glass products must be separated by hand based on their color.  Glass can be recycled indefinitely and is incorporated into glassphalt, which is used in road construction and is made up of 30% recycled glass.

The most successful recycling programs are those in which a deposit is added to the product.  An example is the one for aluminum cans.  The recycling rate is often over 80%.  Aluminum can be recycled indefinitely.  It is melted and in this state is indistinguishable from virgin aluminum.  Recycling aluminum saves 95% of the energy compared to using new aluminum.

Recycled paper is made into pulp.  This is added to pulp from virgin wood.  Recycling causes the fibers in paper to breakdown.  Therefore its quality decreases over time.  Therefore, recycled paper must be used for lower quality items, or new fibers must be added to the process.  Printed and colored paper must be deinked.  Most paper can be recycled.  However, paper coated with plastic or aluminum foil, and ones that are gummed, pasted or waxed are not recycled because it is too expensive.  And gift-wrap paper produces a bad quality product and is therefore discarded.

Table 2 lists the many types of plastics, as found on the Urban Nature Information Service website http://unis.mcgill.ca/.  In the process of recycling plastics, each type must be sorted according to its resin code.  Identification codes 1-6 have been allocated to the six most frequently occurring recyclable plastic resins.  The number 7 has been assigned to all other types of plastic, whether recyclable or not.

Tires can also be recycled.  These can be used for asphalt and rubber mulch for playgrounds.  Clothing is also recycled.  Swapping clothes at exchanges have become popular in places such as universities throughout North America.  A list of what can or cannot be recycled is shown in Table 3, as taken directly from the Urban Nature Information Service website http://unis.mcgill.ca/.  It is important to note that labels should be removed from cans and bottles.  And bottles, etc… should only be cleaned enough to prevent odors so as to prevent wasting water.  Containers with traces of hazardous materials should not be recycled.  And dirty or food stained paper should be discarded.

 

 

Table 2. Plastic (Types of plastics are differentiated by numbers which appear on the containers with the triangle recycling image)

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PET: Polyethylene terephthalate
Soda bottles and oven-ready meal trays.

HDPE: High-density polyethylene
Bottles for milk and cleaning liquids.

PVC: Polyvinyl chloride
Food trays, plastic wrap, plastic juice bottles, water bottles and shampoo containers.

LDPE: Low density polyethylene
Plastic bags and garbage bags.

PP: Polypropylene
Plastic containers, microwaveable trays.

PS: Polystyrene
Yogurt containers, foam trays, hamburger boxes and egg cartons, plastic cutlery, protective packaging for electronic goods and toys.  Currently this type of plastic is not recycled in Quebec.

OTHER: Any other plastics that do not fall into any of the above categories.
An example is melamine, which is often used in plastic plates and cups.

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                     Table 3.  List of Recyclable and Non-Recyclable Items

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                                       Source: Urban Nature Information Service http://unis.mcgill.ca/