As I understand it, Europe has a number of WTE plants throughout the region that supply a good percentage of energy requirements locally. Certainly, the glass and metal components of recyclables collected would have to be sorted out, but the paper (8,000 BTUs per pound) and plastics could go to the WTE plant. Plastics are extremely valuable as energy producers.
According to Penn State University’s Plastic Fuel Project, the mantra should be, “recycle when possible, but if recycling is not an option why not capture the high heat content of plastics?” Its report noted that polyethylene contains 19,900 BTUs per pound; polypropylene has 19,850; cross-linked PE (PEX), 19,780; gasoline, 19,200; and polystyrene, 17,800. In comparison, fuel oil contains 20,900 BTUs per pound (the most of fossil fuels); Pennsylvania coal contains 13,900; and Wyoming coal has 9,600.
|This may look like a detail of an impressionist painting but it's actually a picture of Plastofuel nuggets. Image courtesy Penn State.|
Penn State extruded “logs” of waste plastics that melted the surface of the plastics as it moved through the extruder so that the logs would hold together to be used as a fuel called Plastofuel. They also tested the air quality for three primary emissions—acid gases, particulates and furans/dioxin—and found negligible amounts in each category.
Plastofuel can be easily stored and burned with coal in a coal-fired boiler, or eventually combusted directly in the boiler system, said Penn State’s information. “High-temperature combustion (2,000o F) ensures clean burns with minimal emissions,” said the group’s report. “The key to Plastofuel is that the production process is tolerant of dirt and debris, and because only the outer portions are melted during processing, it requires only about one-tenth the energy to form when compared to producing plastic pellets.”
Obviously, that means minimal sorting and no hot water/chemical baths to remove labels, adhesives and so forth prior to selling the material. That would seem to me to be a very eco-friendly solution to plastic waste and it captures the valuable energy in the plastics waste rather than using valuable fossil fuel energy to create more plastic pellets.
While the PRE calls for “separate collection and high-quality sorting schemes in order to make valuable raw materials,” they might want to consider Penn State’s solution. That would require the use of fewer resources and lower CO2 emissions to collect, transport, sort, wash, grind, transport, reprocess . . . you know the drill. It would also mean capturing the high-heat value of plastics and provide much-needed energy to people in developing countries—to all of us, really—to help offset the need for other types of fuel sources.