BRUSSELS, BELGIUM — Mixed post-consumer plastic packaging waste can be used as an energy-efficient alternative fuel source for the cement industry, according to a study just completed in Switzerland.
The use of plastic waste not only provides for efficient disposal of old packaging but could help to conserve fossil fuels, reduce global carbon dioxide emissions and offer the cement sector a valuable high-temperature substitute energy source, according to the study.
Undertaken by the Association of Plastics Manufacturers in Europe of Brussels; the Swiss Plastics Association of Aarau, Switzerland; and Bundner Cement Untervaz, an Untervaz, Switzerland, cement company, the 2-year study explored the potential of used plastics as a fuel for co-combustion.
The project involved establishing a local, domestic-waste collection system, and sorting, shredding and grinding the waste. The pre-treated plastic was mixed with coal to fuel the BCU cement kiln in Untervaz.
According to the study, dioxin and furan emissions were more than 10 times lower than the most stringent emission guidelines for solid waste incinerators, APME reported. Heavy-metal emissions were negligible, dust levels were ``far below the legally required limit,'' and the waste has a suitably high calorific value for cement production, according to APME.
The project collected plastic packaging waste from 100,000 residents in the city of Zug and a rural area of Graubunden, plus some commercial waste. Sorting and testing reduced heavy-metal contamination.
The waste plastic was ground before being fed into the kiln. According to APME, every 1,960 pounds of plastic waste used saved 2,770 pounds of coal. The results were verified independently by Gesellschaft fur Arbeitsplatz und Umweltanalytik mbH of Munster, Germany.
APME estimated that on a European scale, the cement industry could save as much as 7.4 billion pounds of coal annually by using plastic waste in all cement plants.
``This assumes that all mixed plastics from packaging currently going to landfill is recoverable and used for fuel substitution,'' according to the report.
Fred Mader, APME's deputy director general, said APME has tested mixed plastic waste as a fuel in other European countries during the past four years.
At an interview at APME's offices in Brussels, Mader said the Swiss trial is one of the most promising.
Another trial, at a cement kiln in Wietersdorf, Austria, used packaging recovered through Austria's ARA packaging system, which is similar to Germany's Green Dot program. That study replaced about 20 percent of the coal used in the kiln.
APME also has tested using plastic waste with other conventional fuels, and also a fuel feedstock of 100 percent plastic waste, at small power-generation plants in Scandinavia.
Mader said mixed plastic waste worked better in smaller plants than in Western Europe's huge, coal-fired power plants. There, millions of tons of coal have to be prepared in a particular way, and it is difficult to add small amounts of another fuel with certain properties.