The Yomiuri ShimbunNearly 70 percent of plastic sent to be recycled in Japan is burned in a method called “thermal recycling” or “heat recovery,” prompting specialists to call for a review of the system, which they say contributes to global warming.
The thermal recycling method, which involves burning plastic to produce electricity and for other uses, is becoming a new problem regarding plastic waste.
“Burning petroleum-derived plastic is the same as burning oil, in that it produces carbon dioxide emissions,” said Hideshige Takada, a professor at Tokyo University of Agriculture and Technology. Takada, who specializes in environmental chemistry, calls for the reduction of plastic incineration, adding, “We should prevent more incinerators from being built.”
Minoru Kiuchi, state minister of the environment, also referred to this issue at a Nov. 1 press conference, expressing his “personal opinion” that there “may be a need to gradually shift to other forms of recycling” besides heat recovery.
Currently, 84 percent of all plastic waste is recycled, 9 percent is simply incinerated and the rest is used for landfills or land reclamation, according to the Plastic Waste Management Institute, based in Chuo Ward, Tokyo.
However, of the portion that is “recycled,” 68 percent is used in heat recovery or thermal recycling; only 27 percent is used in “material recycling,” which involves using plastic waste as a raw material to make new products; and 5 percent is used in “chemical recycling,” which involves creating new chemical materials through methods such as breaking down plastics through chemical reactions.
In heat recovery, the heat that comes from burning plastic and other waste is used to turn turbines that produce electricity at power plants or heat swimming pools near incinerators. This is not the image most people have of recycling.
European nations such as Germany and Belgium are working on measures to recycle plastic in ways other than thermal recycling.
In Japan, the period of rapid economic growth caused a sharp rise in the amount of waste, exceeding the capacity of landfills or land reclamation projects. Sanitation was also an issue. As a result, the amount of garbage being burned increased. Problems caused by dioxins and other harmful by-products of incineration have mostly been solved by improving incinerators.
Experiment in Saga
In this context, a facility that removes only CO2 from the emissions given off by a waste incinerator has been operating in Saga since 2016. According to the Saga municipal government, it is technically possible to recover 100 percent of CO2 emissions. However, because of low demand for CO2, currently only about 2.5 percent of the incinerator’s CO2 emissions, or about five tons per day, is being collected.
The CO2 is sent to a company that uses the gas to cultivate algae for producing hand and body creams. “We want to attract more companies,” a city official said.
There also are moves to transform CO2 into other substances. Osaka-based Sekisui Chemical Co. has been conducting a demonstration of transforming the CO2 produced when burning garbage into syngas — basically a mixture of carbon monoxide and hydrogen — to be used in ethanol production.
Hitachi Zosen Corp., another Osaka-based company that manufactures incineration equipment, is developing technology to produce methane gas by mixing CO2 with hydrogen.
Toru Matsumoto, a professor at the University of Kitakyushu who specializes in environmental systems engineering, said, “While we need to cut back on simply burning [plastic], heat recovery technology should also be improved to reduce CO2 emissions.”Speech