Remediation of TCE Contaminated Site by Ozone Micro-Nano-Bubbles
Micro-nano-bubbles (MNBs) technique is a novel technology for remediation of organics-contaminated groundwater. MNBs are tiny bubbles with diameter less than 100 µm, and able to stay stable in water for extended periods of time. Ozone is a strong oxidant which is widely used in wastewater treatment, and ozone MNBs presented high mass transfer efficiency. They can migrate with groundwater flow to reach large affecting area, and efficiently provide dissolved ozone to oxidize organic contaminants in groundwater. In this study, the ozone MNBs were used for groundwater remediation at a trichloroethylene (TCE) contaminated site in Japan. Groundwater was extracted by the extraction well, and pre-treated to remove soil particles and TCE. Ozone MNBs were generated inside the water. H2O2, which can significantly accelerate the oxidation of TCE by ozone, was also added with a mass ratio of ozone: H2O2 of 1:1. Water containing oxidants was injected back into the site through an injection well. The treatment was conducted from 9 am to 6 pm for six days, and groundwater was sampled from monitoring wells to monitor distribution of TCE concentration. The concentration of TCE in groundwater showed significant reduction during the treatment, and an overall removal of 99% was reached after six days. The final TCE concentration in the treated area decreased to below the local permissible limit, and this field application of ozone MNBs presented an efficient new technology for organics-contaminated site remediation.
KeywordsMicro-nano-bubbles (MNBs) Ozone Trichloroethylene (TCE) Field test
The financial support from National Natural Science Foundation of China (Project No. 41372352, 51323014) and Tsinghua University (Project No. 2015THZ02-2, 2015THZ01) are gratefully acknowledged. The support for the testing facility from State Key Laboratory of Hydro Science and Engineering (SKLHSE-2016-D-03) is also acknowledged. The authors thank the assistance of Dr. D Song at IS Solution Company for field monitoring on MNB remediation.
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