Pollution can affect both soil and groundwater. Contaminants can enter the soil and groundwater through settled air emissions, spills and direct discharges. Geologists and engineers use a variety of treatment methods to clean the pollutants from the soil and groundwater. These methods range from slow, passive methods to fast, active systems. Each remediation method has pros and cons depending on the type and severity of the pollution, the geology of the area and the project’s budget and timeframe.
Soil Removal and Groundwater Extraction
Properties that have localized pollution often respond well to simple soil and groundwater removal procedures. You can excavate contaminated soil with a backhoe, contain the soil in a roll off or drum and properly dispose at a landfill or soil treatment facility. You can remove localized groundwater impact using one or more recovery wells by pumping the contaminated water out of the subsurface and treating the water. These methods work for a variety of constituents but become cost-prohibitive if the impact is widespread.
Dual Phase Extraction and Air Sparging
Volatile and semi-volatile constituents respond well to dual phase extraction and air sparging methods. Dual phase extraction treats both soil and groundwater by using a high-powered vacuum pump to extract groundwater and soil vapors. Conversely, air sparge treats groundwater contamination by pumping air into subsurface layers below the water table, causing constituents to volatilize and travel upwards through the subsurface to the atmosphere. Air sparging may use vapor extraction wells in the unsaturated soil zone to help remove volatilized constituents from the upper soil.
