Page 30 - Solid Waste Analysis and Minimization a Systems Approach

8 DEFINITION OF SOLID WASTE ANALYSIS AND MINIMIZATION

■ Phone books. These are made with special glue that breaks down in water. (Some
phone books use glue that interferes with recycling.) Printed in the phone book should
be information on the source and type of paper used, the nature of the binding, and
where phone books can be recycled locally (old Corrugated containers[OCC]).
■ Waxed cartons. These, often used for milk or juice, are plastic laminated on the
inside, even if they don’t have a plastic spout.

The next set of acronyms and abbreviations that is important to understand regards
plastics. The breakdown is as follows:

■ Type 1––PETE (polyethylene terephthalate). Soda and water containers, and some
waterproof packaging.
■ Type 2––HDPE (high-density polyethylene). Milk, detergent, and oil bottles, also
toys and plastic bags.
■ Type 3––PVC (vinyl/polyvinyl chloride). Food wrap, vegetable oil bottles, blister
packages.
■ Type 4––LDPE (low-density polyethylene). Many plastic bags, shrink wrap, and gar-
ment bags.
■ Type 5––PP (polypropylene). Refrigerated containers, some bags, most bottle tops,
some carpets, some food wrap.
■ Type 6––PS (polystyrene). Throwaway utensils, meat packing, protective packing.
■ Type 7––Other. Usually layered or mixed plastic. This generally has limited recy-
cling potential and is disposed at the landfill.

With a little bit of care most plastics can be recycled, and collection of plastics for
recycling is increasing rapidly. Plastic recycling faces one huge problem: plastic types
must not be mixed for recycling, yet it is extremely difficult to distinguish one type from
another by sight or touch. It is usually very important that plastics are separated prior
to recycling. This is due to the fact that plastic recyclers use different processes for dif-
ferent types of plastics, and not all plastics have the same properties, such as melting
points. Thus, it is imperative that they can be separated prior to recycling, either by the
consumer, the hauler, the processor, or the recycler.
Plastic types are generally easy to distinguish, because they are imprinted with a
recycling symbol and a number. The recycling symbol verifies that the material can
be recycled, and the number corresponds to the type of plastic used.

1.2.6 UNITS

In the field of solid waste minimization and recycling, there are two conventions
for quantifying the waste and materials. Quantification is either done by weight
or volume. If by weight, numbers are given in pounds (lb) or more commonly tons
3
(2000 lb = 1 ton). If by volume, then the numbers are given in cubic yards (yd ).
This book incorporates both conventions, because a scale is not used for all waste
audits. Most observations are made by volume and then, using density figures, the
approximate weight is calculated.