ITDI researchers develop solar wastewater detoxification
Manila (26 June) -- Researchers at the Industrial Technology Development Institute, an agency of the Department of Science and Technology trying to develop a technology using sunlight and ordinary cosmetic ingredient to clean industrial wastewater of pollutants, have successfully eliminated pesticides in contaminated water during initial tests.
Trial runs are onstream to treat wastewater contaminated with dyes used in handicraft industry. They 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.
"Eventually, we intend to design and build a simple and inexpensive technology that runs using sunlight and, when that is not available, by using ultraviolet lamps as backup," explains Dr. Christopher M. Silverio, chief of ITDI's Environmental Division.
The technology 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.
In standard photocatalysis, ultraviolet lamps driven by electricity are used. In contrast, solar photocatalyis uses sunlight, which is abundant in tropical Philippines.
"Wastewater, especially those containing harmful chemicals, need to be treated before disposal. Various wastewater treatment processes like filtration, microbial degradation and chemical decomposition are available."
"However, these systems may be cheap but inefficient, effective but costly or the contaminants basically remain as pollutants," says Dr. Silverio.
Solar photocatalysis can completely destroy toxic pollutants into harmless end products without leaving solid residues."
"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," Dr. Silverio added. "It simply involves passing of wastewater through glass tubes packed with titanium dioxide under sunlight."
Different designs have seen successful applications in countries such as the United States and Japan. In Spain, they call it "solar water detoxification."
Solar photocatalysis is virtually unheard of domestically until ITDI researchers thought of ways to use sunlight to remove difficult-to-treat pollutants in wastewater. (PIA-MMIO) [top]