The common remediation methods are physical, chemical, thermal, and biological methods. Table 12.25 compares the advantages and disadvantages of all the
methods.
The criteria for evaluation of the methods, the definitions, and the assigned scores
based on the advantages and disadvantages of the methods are listed in Table 12.26.
Table 12.27 provides the final comparative results of the methods. The results of
the analysis based on the oil spill response methods indicated the highest score
(73) for bioremediation. Economic and the environmentally friendly properties of
bioremediation are its two important advantages and its main limitations are timeconsuming treatment, low response of microbes to high concentrations, the biodegradability of limited hydrocarbons, influenced by the environmental factors, and the
heterogeneity of marine oil spill (Dave and Ghaly 2011).
For in situ burning, score 59 was obtained, but it cannot be used for all the areas of
oil spill. Score 55 was for booms and skimmers that are useful for all kinds of oils but
their efficiency is highly dependent on the conditions of sea and weather. Score
54 was obtained for dispersants, which are always applied to bioremediation
processes.
As a conclusion and according to the information of Table 12.25 and the scores
discussed in Table 12.27, bioremediation can be the best choice if the situation is
appropriate for its performance. However, to have the best efficiency, a combination
of all the methods provides the highest level of remediation.
12.7 Conclusions
Oil-polluted water has harmful effects on marine life and human health. Immediate
action is required to remove oil spills. The choice of an appropriate removal method
depends on the site conditions, limitations of the method, and environmental
considerations.
Physical methods are eco-friendly but these are expensive and time-consuming
methods requiring a large number of personnel and equipment and are not feasible in
harsh sea conditions and brush or broken ice conditions. In situ burning methods
produce a large amount of secondary pollutants like CO 2 , which may have irreparable effects on marine life. Therefore, these methods are not recommended at any
time. Chemical agents can be used to improve other removal methods like skimmers,
while some types such as dispersant agents break the oil components and oil
recovery is impossible in such conditions.
Sorbents have excellent sorption and recovery performance because of their high
sorption capacity, porous structure, low density, high specific surface area,
oleophilicity, and reusability. Synthetic and modified inorganic sorbents have
greater oilsorption capacity than natural sorbents. Nevertheless, secondary pollution
is a major disadvantage. On the other hand, natural sorbents have no significant
resistance during reuse cycles. Therefore, composition of natural or inorganic and
synthetic sorbents can modify the defects of both types of sorbents.
12 Remediation of Pollution by Oil Spills
485
methods.
The criteria for evaluation of the methods, the definitions, and the assigned scores
based on the advantages and disadvantages of the methods are listed in Table 12.26.
Table 12.27 provides the final comparative results of the methods. The results of
the analysis based on the oil spill response methods indicated the highest score
(73) for bioremediation. Economic and the environmentally friendly properties of
bioremediation are its two important advantages and its main limitations are timeconsuming treatment, low response of microbes to high concentrations, the biodegradability of limited hydrocarbons, influenced by the environmental factors, and the
heterogeneity of marine oil spill (Dave and Ghaly 2011).
For in situ burning, score 59 was obtained, but it cannot be used for all the areas of
oil spill. Score 55 was for booms and skimmers that are useful for all kinds of oils but
their efficiency is highly dependent on the conditions of sea and weather. Score
54 was obtained for dispersants, which are always applied to bioremediation
processes.
As a conclusion and according to the information of Table 12.25 and the scores
discussed in Table 12.27, bioremediation can be the best choice if the situation is
appropriate for its performance. However, to have the best efficiency, a combination
of all the methods provides the highest level of remediation.
12.7 Conclusions
Oil-polluted water has harmful effects on marine life and human health. Immediate
action is required to remove oil spills. The choice of an appropriate removal method
depends on the site conditions, limitations of the method, and environmental
considerations.
Physical methods are eco-friendly but these are expensive and time-consuming
methods requiring a large number of personnel and equipment and are not feasible in
harsh sea conditions and brush or broken ice conditions. In situ burning methods
produce a large amount of secondary pollutants like CO 2 , which may have irreparable effects on marine life. Therefore, these methods are not recommended at any
time. Chemical agents can be used to improve other removal methods like skimmers,
while some types such as dispersant agents break the oil components and oil
recovery is impossible in such conditions.
Sorbents have excellent sorption and recovery performance because of their high
sorption capacity, porous structure, low density, high specific surface area,
oleophilicity, and reusability. Synthetic and modified inorganic sorbents have
greater oilsorption capacity than natural sorbents. Nevertheless, secondary pollution
is a major disadvantage. On the other hand, natural sorbents have no significant
resistance during reuse cycles. Therefore, composition of natural or inorganic and
synthetic sorbents can modify the defects of both types of sorbents.
12 Remediation of Pollution by Oil Spills
485