A university research team has developed an efficient and lower-cost biotechnological method for treating volatile organic compounds (VOC) produced by semiconductor and photonics plants.
National Science Council Deputy Minister Chang Ching-fong (張清風) told a press conference yesterday that the technology — developed by a research team from National Chiao Tung University in a project funded by the National Science Council (NSC) — conforms with environmental protection regulations and would benefit local industries.
Tseng Ching-ping (曾慶平), a professor at the university’s department of biology and technology and project commissioner, said activated carbon is commonly used to absorb VOC emissions from electronics manufacturing plants, but treatment efficiency varies when different substances are involved.
Moreover, the regeneration process of the saturated activated carbon by heating consumes energy, produces a certain amount of air pollution and costs a lot more than the team’s new biotechnological method, the team said.
After analyzing VOC emissions from semiconductor and photonics plants, the team found that the most common organic compounds found in emitted waste gas were acetone, isopropyl alcohol and propylene glycol monomethyl ether acetate, Tseng said.
The team selected out three to five types of microorganisms, from more than 1,000 candidates, which are more effective in decomposing the water-soluble compounds and showed a purification rate of above 90 percent in short-term monitoring results.
The decomposition rate on non-water soluble compounds is only about 60 percent at present, so it still needs modification if used in other industries, such as coating factories or gas stations, Tseng said.
However, according to the monitoring results of bioreactors installed in a cooperating factory, long-term efficiency has reached more than 85 percent, which is the standard set by the Environmental Protection Administration, Tseng said.
“The initial cost of installing the bioreactors is much higher than [using] activated carbon,” Tseng said.
“However, to produce the same VOC purification rate, the maintenance of activated carbon systems each year costs about NT$13 million [US$429,000] more than that of a bioreactor,” he said.
Cleaning the activated sludge produced annually by a bioreactor is enough to keep the system running, which is also easier and cheaper to operate than an activated carbon system, Tseng said.
The study gives industries a new choice to deal with gas emissions and promote environmental protection and sustainable development, the council said.
Tseng said the team had already obtained patents in the US and Taiwan and would continue to develop methods for extending the technology to other industries, such as sewage treatment or biogas purification.