Biofouling on ships' hulls can reduce the performance of the vessel and increase its fuel requirements Biofouling is also found in almost all circumstances where water based liquids are in contact with other materials. Industrially important examples include membrane systems, such as membrane bioreactors and reverse osmosis spiral wound membranes cooling waters cycles of large industrial equipments and power stations . Biofouling can also occur in oil pipelines carrying oils with entrained water especially those carrying used oils, cutting oils, soluble oil or hydraulic oils. Anti-fouling is the process of removing the accumulation, or preventing its accumulation. In industrial processes, bio-dispersants can be used to control biofouling. In less controlled environments, anti-fouling coatings which contain biocides or non-toxic coatings which prevent organisms from attaching can be used.