ITDI developing new method to clean industrial wastewater

MANILA, Philippines – Researchers at the Industrial Technology Development Institute (ITDI) are developing a technology using sunlight and an ordinary cosmetic ingredient to clean industrial wastewater of pollutants.

“The project is aimed at treating wastewater contaminated with dyes used in handicraft industry,” said Christopher Silverio, chief of ITDI’s Environmental Division.

The technology, he said, is called solar photocatalysis, a promising technique that uses sunlight and titanium dioxide, a non-toxic chemical commonly used as white pigment in paints and cosmetics, to break down toxic and hard-to-remove pollutants.

Photocatalysis occurs when a relatively small amount of light-absorbing material called photocatalyst chemically reacts with pollutants without itself being consumed. In this case, the photocatalyst used is titanium dioxide, Silverio said.

“Our technology is also designed so that it will be cheap, easy to operate, and does not need filtration process that limits its commercial feasibility in the past,” Silverio said.

“It simply involves passing of wastewater through glass tubes packed with titanium dioxide under sunlight,” he said.

In standard photocatalysis, ultraviolet lamps driven by electricity are used. In contrast, solar photocatalysis uses sunlight that is abundant in tropical Philippines, Silverio said.

“Wastewater, especially those containing harmful chemicals, needs to be treated before disposal. Various wastewater treatment processes like filtration, microbial degradation and chemical decomposition are available,” Silverio said.

“However, these systems may be cheap but inefficient, effective but costly or the contaminants basically remain as pollutants,” he added.

Silverio said solar photocatalysis could completely destroy toxic pollutants into harmless end-products without leaving solid residues.

“We hope to help cottage dyeing industries comply with strict regulations imposed by countries that rigorously monitor the environmental impact of exporters and their manufacturing activities,” Silverio said.

Silverio said the technology is being used in the United States, Japan and Spain. In Spain, they call it “solar water detoxification.”

The ITDI is an agency under the Department of Science and Technology.