Due to the limited efficiency of oil recovery systems in real conditions and in presence of waves the amount of water in the temporary tanks is too high.
Depending on the environment the negative consequences can be increased.
In an industrial environment the cost of treatment (separation / purification) of oil / fat increases proportionally to the amount of water as waste managers will charge us per cubic meter treated: the presence of water multiply the cost. Furthermore, if the recovered substance is treated in situ, operating costs will rise due to the increase of pumps consumption and worsening performance in addition to increasing the processing times.
In a marine environment, in response to an oil spill, in addition to the previous problems a deterioration and a significant increase of the complexity of the operating conditions may occur. Temporary tanks of oil spill response vessels present during recovery operations reduce their autonomy as an important part of the volume is water. To avoid this problem vessels are forced to be equipped with a oily water separation system so that the separated water can be returned to the sea. This separation system should be approved by international maritime authorities, fully certified for IMO MEPC and comply with international (as MARPOL 73/78) and local regulations, which may be more restrictive than the first ones.
In any case, as we shall see, separation time increases and makes operation and installation more expensive.
In summary, we found a series of problems caused by the ineffectiveness of the recovery means:
- Reduction of the autonomy of the cleaning systems
- Increased problem resolution time, as the process does not end with the pumping of the recovered substance from the skimmer to the storage tank.
- Increase in installation costs, as required further and complex separation systems.
- Increased operating costs, since the presence of water multiplies pumping energy consumption and separation systems operation.