Soil and Groundwater Contamination Survey and Countermeasure Technologies
| Category of Tchnology | Treatment | Emission Control | |
| Media | Soil Gas, Others (Off-gas from the Stripper) | ||
| Contaminants |
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| Applied (Demonstrated) Substances | Trichloroethylene (TCE) | ||
| Scope | Concentration Range | In the case of the concentration of influent is over 2,500ppmv, it will be fed with fresh air to dilute for avoiding damage for catalyst reactor and heat exchanger. | |
| Hydrogeological Conditions |
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| Chemical Soil Properties | |||
| Other Remarks | |||
| Technology Description | Classification | Decomposition | |
| Status |
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| Outline of Technology | The soil vapor contaminated with VOCs is induced to gas-liquid separator to remove mist and sand particles. The vapor is induced to heat exchanger to pre-heat by exhaust gas. After heated by electric heater, the soil vapor is led to reactor to decompose VOCs. The reactor is filled by honeycomb structure Ti-Si complex catalyst. The gas generated by the oxidation reaction is exhausted after washed and neutralized by alkali scrubber to remove hydrogen chloride. | ||
| Required Pre- and Post-treatment | Soil vapor extraction system or pumping aeration system is necessary as pre-treatment stage. If the harmful components generate contingently, the exhaust treatment device is necessary. | ||
| Enhance Effectiveness through Combination | |||
| Case History | In case of inlet temperature of vapor is set to 350°C,
it is obtained 99.5% of removal ratio as VOCs, even the space velocity
(SV) is set to 3000 1/h.
In this case, the influent concentration 1000ppmv, the effluent concentration is 3ppmv. |
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| Application Examples | |||
| Limitations | |||
| Properties of Treated Soil |
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| Schematic Flow Process |  |
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| Applicability | In Situ Applicability | Possible | |
| Ground Structures |
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| Required Excavation | |||
| Groundwater Extraction | |||
| Required Space | 8m2 of floor space are necessary to install this system. | ||
| Operational Time | |||
| Installation Time | |||
| Maintenance and Control Requirements | Monitoring items; flow rate of soil vapor, concentration of influent and effluent gas, conditioning of solution in regard to alkali scrubber. | ||
| Additional Remarks | |||
| Secondary Impacts to Environment | Secondary Treatment Required? | Off-gas Treatment | |
| Effects on Living Environment | |||
| Additives | Air | ||
| Possibility of Contaminant Spreading | There is no emission of contaminants, if treatment of exhaust gas is performed adequately. | ||
| Secondary By-products | For reaction in high temperature, there is a possibility generating harmful components. | ||
Soil Environment Management Division, Water Environment Department, Environmental Management Bureau, Ministry of Environment
Tel: +81-3-5521-8319
E-mail: MOE@env.go.jp
