Integrated chemical and biological treatment of polychlorinated biphenyl and dichloro diphenyl trichloroethane.

摘要

Sediment contaminated by persistent, bioaccumulative, and toxic compounds (PBTs) such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and dichloro diphenyl trichloroethane (DDT) is a significant national and international concern. Currently there are no economically and technically practicable technologies for in situ treatment of PBTs contaminants in sediment. This research work develops an innovative remediation approach by integrating chemical and biological treatment to remediate highly recalcitrant PBTs in sediment, detoxify PBTs by reactions with ozone enhanced by using ultrasound and acetic acid and promote natural bioremediation. The major tasks are performed to evaluate the combination treatment process with respect to: (1) degradability, intermediates, kinetics and pathways of PCB congeners and DDT under ozonation in carbon tetrachloride (CC14) solution; (2) feasibility of integrated chemical and biological treatment for PCB and DDT spiked sediment; (3) treatability of integrated process for PCB and PAH contaminated real sediment; and (4) process parameters optimization including O3 concentration, contact time, pH, the use of ultrasonic irradiation and acetic acid. The results indicate that the integrated process, using ozonation aided by ultrasound and acetic acid as a pretreatment, followed by conventional biological treatment, is seen as practicable and proved capable of treating sediments contaminated with PBTs.