Treatment of Bilgewater
Every ship, whether it is a container ship, an oil tanker or a freighter, produces bilgewater which poses an acute disposal problem. The IMO (International Maritime Organization) specifies that bilgewater may be discharged into the sea only if its residual oil content is below 15 ppm. GEA's BilgeMaster satisfies this limit value by a considerable margin. At the same time, the oil recycled from the separation process can be used for a variety of purposes.
What is bilgewater?
Bilgewater is created by leaks of salt water, cooling water, fuel oil and lube oil, by the dewatering of sedimentation and sludge tanks, by the draining off of various cleaning processes and also by particles of soot and dirt. Before there is any question of discharging this into the sea, IMO regulations specify that this explosive mix has to be treated so intensively that its residual oil content is below 15 ppm. However, this minimal pollution cannot be realized cost-effectively using conventional separation techniques.
Oil content to < 5 ppm possible
The solution is the GEA BilgeMaster system. The separators of this system can cope with 200 to 7000 liters an hour and even in the standard version cut residual oil content to below the statutory minimum. Under normal bilgewater feed conditions, the residual oil content in the pure water effluent is 10 to 12 ppm. Add-on units make it possible to reduce the oil content to < 5 ppm so that de facto pure water can be discharged into the sea.
Recycled oil can be reused without difficulty
The economic benefit of this oil-water separation system is in the particular lasting nature of the investments. Oil recycled out of the separation process can be reused as fuel oil, for example. Recovered lube oil can be used as a fuel to generate heat. What is more, the system is self-cleaning and designed for unsupervised operation so that no additional staff are required. On the other hand, alternative methods such as static separation using sedimentation tanks or filtration, for example, require either cost-intensive manual cleaning from time to time or the replacement of filter elements. In addition, chemicals are frequently also required which are not only expensive, but in turn can also present a hazard to the environment.