Remediation refers to the removal, destruction, or transformation of contaminants to less harmful
substances. To treat contaminated sites, physicochemical and biological remediation can be conducted.
Among the highly potential approach is bioremediation since many studies have reported of its
effectiveness in removing numerous pollutants from many contaminated sites [3,4,6]. Generally,
bioremediation technologies can be classified as in situ or ex situ. In situ bioremediation involves treating
the contaminated material at the site while ex situ involves the removal of the contaminated material to be
treated elsewhere [7]. Different techniques are employed depending on the degree of saturation and
aeration of an area. In situ techniques are defined as those that are applied to soil and groundwater at the
site with minimal disturbance. Ex situ techniques are those that are applied to soil and groundwater at the
site which has been removed from the site via excavation for soil or pumping for water [8]. It mainly
involved biostimulation where organic or inorganic components were introduced to enhance indigenous
microbial growth that directly degrades the contaminants.