A thesis proposal in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management Inter-University Program on Emvironmental Toxicology, Technology and Management, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology - Chulabhorn Research Institute - Mahidol University, 2007

PCBs are synthetic compounds that have been widely used as transformer dielectric fluids, heat transfer fluids, and plasticizers. They are not easily degraded and can cause toxic effects to humans and animals. This study was carried out to investigate efficiency of PCB degradation by ozonation catalyzed by TiO2. A 300-ml lab scale reactor was filled with a synthetic wastewater containing PCB concentration at 1 and 5 mg/L, ozone concentrations were varied at 10 and 25 mg/L, Ti02 concentrations were varied at 3, 5, and 9 mg/L, and pH of the synthetic wastewater was varied at 3 and 9. The conditions that resulted in about 99% PCB removal were as follows: ozone dosage 900 mg-min/L; contact time 90 min; Ti02 9 mg/L; and pH 9. The first-order reaction rate constant of PCB removal under these conditions was found to be 0.0919 min-1. The efficiency of PCB degradation was found to increase with increasing TiO2, pH and contact time. Since Ti02 is a catalyst which produces synergistic effects with ozone on PCB degradation and high pH produces more OH radicals which activate the oxidation reactions, the higher these values were maintain in the reactor the more PCB degradation. The operation cost of ozone catalyzed by Ti02 for PCB degradation under the above condition was found to be US$ 1.21 /mg of PCB, which was lower than some conventional techniques employed for PCB degradation. The PCB reaction rate constant as found in the study could be applied determine the ozone reactor size, contact time, and the amount of ozone and TiO2 needed for PCB degradation