Degradation of chlorinated volatile organic compounds from contaminated ground water using a carrier-bound TiO2/UV/O3-system

Abstract

In the present work, a suitable experimental setup was developed to successfully apply advanced oxidation processes (AOP) to real groundwater matrices. This setup combines an O₃-bubble column reactor with a carrier-bound TiO₂/UV-system. The degradation of various chlorinated ethene and methane derivatives commonly found of chlorinated volatile organic compound polluted regional groundwater samples was investigated. Because of known issues within water remediation using AOP such as toxification by transformation products, this study aimed at complete mineralization of the contained organic micropollutants. Moreover, the influences of variable process parameters such as flow rate, ozone concentration, and radiation dose on process performance were statistically evaluated and discussed. Parameter optimization using a Box-Behnken experimental design resulted in very promising degradation rates. It was thus possible to achieve a degradation rate of at least 98% for cis-dichloroethene, trichloroethene and tetrachloroethene and 85% for trichloromethane without formation of transformation products. The results of this work open up the possibility of developing innovative technologies based on AOP, which can be universally applied even to challenging matrices such as groundwater.

Keywords: Advanced oxidation processes; Groundwater remediation; Hydroxyl radical; Photocatalysis; VOC mineralization.