Removal of Toluene from Unsaturated Sands by Ozonation

• Main Authors: Che-min Yu, 余哲民
• Other Authors: 李孫榮, 宋孟浩
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/45393635989035163048

碩士 === 嘉南藥理科技大學 === 環境工程與科學系碩士班 === 96 === Abstract Toluene, a major constituent in gasoline, is toxic and harmful to human. It could contaminate soils when gasoline leaks from its storage tank. The objective of this research is to evaluate the removal efficiency of ozone venting in treating toluene-contaminated soils. Experiments were conducted at three different flow rates (i.e., 200 ml/min, 100 ml/min, 50 ml/min), tow different water saturations (i.e., 4%, 8%), three different toluene volumes (i.e., 0.5 ml, 1 ml, 2 ml, 4 ml) , and two different soil particle sizes ( 0.125~0.375 mm, 0.475~1 mm). When nitrogen gas was controlled at 200 mL/min, toluene concentration dropped to 18 ppm within 90 pore volumes to 1 ppm within 200 pore volumes. On the other hand, when ozone gas was controlled at 200 mL/min, toluene concentration dropped from 7 ppm within 200 pore volumes to 22 ppm within 90 pore volumes. This proves that ozone gas is more efficient than nitrogen gas in removing toluene. As different flow rates (i.e., 200 ml/min, 100 ml/min, 50 ml/min) of ozone were applied, it was found that the flow rate of 200 mL/min has the highest removal efficiency. Also it was found that at the particle size range of 0.475~1 mm, its removal efficiency is better than at 0.125~0.375 mm. Finally, it was found that at a higher saturation of 8% the removal efficiency was greater than at a lower saturation of 4%. Keyword: Toluene, Ozone, unsaturated layer of soil, PV