Recycling of Plastic Packaging
In the U.S., recycling of plastic packaging began, on a limited scale, in the 1970s with recycling of PET soft drink bottles and HDPE milk bottles. Milk bottles were collected almost exclusively through drop-off programs, where people would bring clean empty bottles to some central location where they would be collected. Because only crude processing methods were available, labels on the milk bottles were a significant contaminant. Many programs asked residents to remove the labels, but in general met with extremely limited success. In Grand Rapids, Michigan, in one of the early programs, workers at the processing facility cut the labeled section of the bottle out with a utility knife and discarded it before sending the rest of the bottle through the grinder, in order to meet the purity requirements of the user. The recovery rate in such programs (amount of material collected for recycling compared to the amount available) was extremely low.
Recycling of PET soft drink bottles was considerably more successful. The existence of bottle deposit programs m nine states (ten if California's refund value system is included) provided a pool of collected material of consistent quality. Therefore, the early recycling efforts focused primarily on the processing and end use parts of the cycle. PET recycling also had the advantage of PET having superior properties and higher value than HDPE. By the mid 1980s, the PET recycling rate hovered around 20% in the U.S., almost exclusively due to recycling of deposit containers. There was some additional recycling of PET in non-deposit states, much of it through the Beverage Industry Recycling Program (BIRP), which was designed primarily to combat the passage of deposit legislation in additional states. Collection rates in these programs, even though some paid consumers for the containers they delivered, was comparable to those in the drop-off HDPE milk bottle programs. Deposit programs, on the other hand, generally had redemption and recycling rates approaching 90%, or sometimes even higher.
The definition of recycling rates requires some discussion. Until the late 1990s, the American Plastics Council calculated recycling rates as the amount of recovered material delivered to new markets divided by the amount of material available for collection, converted to a percentage. In the late1990s, the APC changed the method of calculation to use the amount of material delivered to the processing center, rather than the amount coming out of the door for reuse, as the numerator. Since there are losses associated with recycling, including unwanted materials which are mistakenly included, the effect of this decision was to inflate recycling rates. APC argued that this action simply brought the plastics industry's method of reporting on recycling rates in accord with the methodology used in other industries. It certainly is true that this is the method of reporting recycling rates that is used in the paper industry. The glass industry, in addition to using quantities based on the amount of material delivered for processing, uses a formula that counts refillable containers as if they were recycled several times. In the metal industries, however, the calculation of recycling rates is based on the usable amount, rather than the total delivered amount. The change in methodologies sparked heated criticism from some environmental groups. It is likely that the fact that the change in methodology occurred at the same time as the first decrease in plastic recycling rates after a period of rapid growth, whether coincidental or not, increased the criticism. Therefore it needs to be recognized that recycling rates reported by different entities may differ in both the data that is used to determine the rate, and in the formula used for determining the rate from the data. Recycling rates coming from the U.S. EPA Office of Solid Waste are usually based on industry reports about the amount of material recycled, so the differences in methodology affect that data, as well.