IN-SITU REMEDIATION, APPROPRIATE TECHNIQUES


In situ remediation technologies deliver rapid and cost effective treatment of sub-surface pollutants. With careful design they can significantly reduce the impacts associated with long-term remediation programmes through shortening of remediation timescales, avoidance of high volumes of plant and traffic movements or reduction in energy consumption and waste generation.


Chemical oxidation and reduction are rapid techniques, used to drive chemical reactions and destroy or fix pollutants and are typically employed to treat higher concentrations. Chemical oxidation and reduction applications are not “magic bullets,” having the potential to be both beneficial and detrimental, if applied hastily or incorrectly.


Thermal enhanced technologies offer an alternative approach to contaminant mass recovery and destruction. Whilst energy consumption is increased the technique can deliver sustainability gains through shorter remediation timescales, reducing traffic movements and limiting waste. Safety is a major consideration and thermal enhanced technologies require careful design and planning.


In-situ bioremediation (accelerated natural attenuation) uses the application of reagents to engineer optimum conditions for microbiological populations to degrade subsurface pollution. Techniques typically focus on generating aerobic or anaerobic conditions, together with the delivery of more readily available carbon sources to assist in the co- metabolism of pollutants.


These techniques are frequently used as complimentary technologies in a treatment train. However, the impacts of the harsh subsurface environment generated by the chemical or thermal treatment phases must be considered to ensure that the secondary biological treatment stage will succeed.


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