4.2.2. Ex Situ Bioremediation Techniques

Ex situ technologies are remediation options where the affected soil (excavation) and water (pumping) are removed from their original location and cleaned on-site or off-site. The most important ex situ bioremediation treatment processes include landfarming, biopiles, and composting. The advantages and disadvantages of these techniques are given in Table 4.2.

Land farming

These technique applications are the easiest and most effective method for petroleum contaminated soil. The main aim is to situmulate natural biodegradative organisms and to facilitate their aerobic degradation of pollutants. Land farming received much attention as a disposal alternative technique because it has the potential to reduce monitoring and maintenance costs, as well as clean-up liabilities. However, the practice is limited to the treatment of superficial 10–35 cm of soil.

Composting

Composting method is the process of degrading organic wastes by microorganisms under thermorphilic condition (40-65°C). This method has been applied to soils and biosolids contaminated with petroleum hydrocarbons, solvents, chlorophenols, pesticides, herbicides, PAHs, and nitro-aromatic explosives.

Biopiles

Biopile is a bioremediation technology in which land farming and composting are used as a hybrid system. This technique, which is a refined version of land farming that tend to control physical losses of the contaminants by leaching and volatilization is used for treatment of surface contamination with petroleum hydrocarbons. Biopiles have been considered as a feasible, cost effective and less destructive remediation technique for petroleum contaminated soils.

Table 4.2. Advantages and disadvantages of ex situ techniques