ISTH: Pilot test and refurbishment in Beijing, China
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- Pilot test on 900m², remediation area 12,000m²
- 33 burners in the pilot, approx. 500 for remediation
- Heating of the substrate to at least 270°C
Thermal refurbishment of a former steelworks
The site of a former steelworks has massive contamination of the subsoil by PAHs, BTX and coke oven-specific pollutants. With a view to large-scale remediation of the entire site, a three-month pilot test was carried out to demonstrate the suitability of in-situ thermal remediation (ISTH) using solid heat sources in the unsaturated soil zone. The test field had an area of approx. 900 m² and reached 9 m below ground level.
In the pilot, the subsoil was heated to at least 270 °C with the aid of 33 gas-fired heat sources, whereby the extracted pollutants were oxidized via the gas burners. After cooling the exhaust gas stream, fine cleaning was carried out using downstream activated carbon adsorption. Multiple temperature sensors continuously monitored the temperature development and heat propagation underground.
Since mid-2018, large-scale ISTH remediation has been carried out with 750 gas burners on a highly contaminated area of approx. 12,000 m² up to 5.5 m uGOK.
Scope of services
- Pilot test
- Large-scale ISTH refurbishment:
- 750 gas burners with around 1,500 heating lances
- 3 container systems for the collection and treatment of soil air for 16,000m³/h each
- 3 high-temperature flares for 1,000m³/h each for the treatment of highly contaminated soil air
- Temperature monitoring via several hundred temperature sensors
- Concept, detailed planning and execution