GROUNDWATER/LEACHATE/CONTAMINATION IN WATER : IN SITU CHEMICAL/PHYSICAL TREATMENT
Thermal Treatment
Typical Thermal Treatment for Contaminated Water
Process:
Steam is forced into an aquifer through injection wells to vapourise volatile and semivolatile contaminants. The vapourised components rise to the unsaturated (vadose) zone, where they are removed by vacuum extraction for treatment.
Hot water or steam-based techniques include:
Uses:
Cost:
- Highly variable - dependent on the number of wells required per unit area, site geology, duration of treatment, the soil type and depth & type of contaminants.
- e.g. shallow contamination - requires closer well placement & lower operating pressures (to prevent soil fracturing), hence increasing the cost.
Steam is forced into an aquifer through injection wells to vapourise volatile and semivolatile contaminants. The vapourised components rise to the unsaturated (vadose) zone, where they are removed by vacuum extraction for treatment.
Hot water or steam-based techniques include:
- Steam Injection and Vacuum Extraction (SIVE )
- In Situ Steam-Enhanced Extraction (ISEE )
- Steam-Enhanced Recovery Process (SERP ).
- Contained Recovery of Oily Waste (CROW )
- The effectiveness is dependent on soil type, contaminant characteristics & concentration, geology/hydro-geology.
- Further in situ biological treatment is often required to treat the water until contaminant concentrations are again satisfactory.
- Hot water/steam injection is typically short-medium term (few weeks-several months).
- It can be enhanced if the chemicals are incorporated with the hot water during the process.
Uses:
- Target contaminant groups: VOCs, SVOCs & fuels - typically found at manufactured gas plants, wood-treating sites, petroleum-refining facilities, and other sites with soils containing light to dense organic liquids.
- Applicable in both deep and shallow contaminated areas.
Cost:
- Highly variable - dependent on the number of wells required per unit area, site geology, duration of treatment, the soil type and depth & type of contaminants.
- e.g. shallow contamination - requires closer well placement & lower operating pressures (to prevent soil fracturing), hence increasing the cost.