Physical Remediation
Pump and Treat
Simple technique where the impacted groundwater is pumped above ground and passed through a series of treatment modules and either returned to the ground or disposed of to foul sewer.
Soil Washing
Soil washing is in essence a wet screening process. Materials are mixed into a suspension with water and screened and segregated at various stages of the process to produce aggregates, sand silt and wash water. Soil washing of contaminated materials usually results in a remediated coarse fraction with contaminated silts and water.
Dual Phase Vapour Extraction
This remediation technique involves the removal and recovery of groundwater, ground vapours and free product using a vacuum. Any free product is treated and separated using similar methods to more traditional pump and treat techniques.
In-Ground Barriers.
In-ground barriers can either be installed using piling rigs or through more traditional civil engineering techniques such as excavation. Barriers can either be impermeable, or permeable reactive. Permeable reactive barriers are barriers which allow the passage of groundwater be treat/ or react with contaminants contained within the groundwater. They are usually formed used modified clays and cement mixtures.
Impermeable barriers can be formed using sheet steel piles, concrete piles or cement bentonite mixes. The permeable barrier can also be formed as a soil mixed barrier or a straight soil replacement barrier.
Simple Segregation
Segregation by either a dry screener or a machine bucket is often overlooked as a form or remediation. It is low tech but when it is used as a stand alone remediation technique, or if it is used as a preliminary technique to reduce the material being treated by other remediation techniques it is very effective in reducing cost and programme.
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