Remediation Of Contaminated Sites

EXECUTION OF REMEDIATION PROJECTS

REMEDIATION PROCESS OF CONTAMINATED SOIL USING A THERMAL DESORPTION PROCESS

Thermal desorption is a remediation process for contaminated soil, sludges, residues and other substances. Desorption is a back to front absorption, in this instance an evaporation of organic contaminants and petroleum derivatives that have contaminated soil.

There is a pre-treatment in which the soil is screened and homogenized prior to entering the desorption unit, a rotating drum like furnace in which the temperature is sufficient to volatise humidity and the contaminant hydrocarbons.

Gases from this process are forced through a bag filter that retains solid particles and subsequently an incineration stage eliminates the last inorganic particles. The residue of fully decontaminated soil passes through a cooler from where it can return “to nature”.

ADVANTAGES

• This is a highly adaptable process finding applications with numerous substances for which the contamination problem stems from petroleum and its derivatives that are volatile organic compounds (VOC), semi volatile organic compounds (SVOC) and polyaromatic hydrocarbons (PAH).
• It is an effective process that is guaranteed to remove 99.5% of hydrocarbon pollutants.
• The process eliminates not only contaminant solids but disposes effectively of the gases generated during the process.
• The desorption equipment is transportable and operates in situ, which is to say the machine goes to the place where there is a problem, thus avoiding costs and inherent risks accruing to the handling, temporary storage and transport potentially dangerous materials.
• The process is self contained and automatic in all its stages.

Biopiling is a remediation process used for soil contaminated with hydrocarbons. The process accelerates the action of microbes normally found in the soil by aeration, humidity control and nutrients such as nitrogen and phosphorous, as well as substances that improve the soil structure Aerobic microbe activity degrades hydrocarbons thus reducing their concentration.

Biopiling starts by laying out impermeable mats to avoid seepage of leachate and soluble compounds into the subsoil. Before building the pile a network of air pipes connected to an air blower are installed, the function of which is to aerate and further accelerate the process. It is usual to cover the piles with a tarpaulin to protect them from wind and rain and to prevent the escape of contaminates material into the immediate environment.

Advantages

• Natural process without harmful side effects;
• Flexible process allowing corrections during operation;
• Presents a cost / benefit very attractive compared to other treatment methods.