Contaminated groundwater on an industrial site can be a huge problem and turn into a serious liability for a company very quickly. The type of treatment that is best for a particular site with contaminated groundwater is based on the type of contaminant that is present, the geology of the site, and the amount of time that there is to treat the contaminated water.
Pump-and-Treat
Pump-and-Treat: Groundwater is pumped up to the surface and treated in above ground facilities. After treatment the water is released into the environment or is re-injected into the subsurface. Pump-and-Treat is suitable for a number of contaminants including dissolved metals and chlorinated solvents. It can be very effective for immediate containment of a defined plume.
Permeable Reactive Barriers
A long-term solution, which can be implemented before a final solution is found, is to dig a trench filled with reactive material, for example zero-valent iron. The contaminated groundwater will flow through this “Permeable Reactive Barrier” and be treated naturally. This solution is low in maintenance and is ideal for sites where ongoing operations make it impossible to set up a solution for the contaminated groundwater.
In-Situ Chemical Oxidation
Peroxide-based In-Situ Chemical Oxidation (ISCO) systems utilising hydrogen peroxide (##O2) and persulphate (ΟΣ.Params.-) are effective for remediating groundwater contaminated with petroleum hydrocarbons, chlorinated solvents and other closely related organic contaminants found at source zones.
Air Sparging
Air Sparging: Introduce air under the water table to volatilize dissolved contaminants that are then collected by a soil vapour extraction (SVE) system above. Air sparging is highly effective for recovery of light non-aqueous phase liquids (NAPL) such as petroleum products and other volatile organic compounds (VOCs), particularly fuel spills and BTEX compounds.
Monitored Natural Attenuation
Natural attenuation, or monitored natural attenuation, can be used at industrial sites where contamination is at low levels and where natural processes can decrease concentrations of contaminants in the subsurface over time. Naturally occurring bacteria and chemicals in the soil and groundwater can degrade a variety of contaminants, and because of this, natural attenuation can be used as a long-term remedy. Groundwater remediation can be achieved through monitoring of the naturally occurring processes that degrade contaminants in the subsurface.
There is more on Groundwater Remediation at //soilfix.co.uk/services/groundwater-remediation. The US EPA has a list of the Ground Water Remedy Technologies that are currently recognised.
Choosing the right groundwater remedy early on can save time, money and prevent a multitude of regulatory problems.
