During normal everyday use many processes can become contaminated or fouled by bacteria or sea life. However, this is normally controlled by continuous dosing of biocide such as copper/chlorine from an electro chlorination unit for seawater cooling or regular planned treatments such as glutaraldehyde or THPS. Over time electro chlorination units can fail or resistance to regularly used biocides can build up and bacteria and sea life can take hold and foul the system.
Fouling can cause a range of issues from corrosion which can cause a localised failure of a pipe wall to loss of flow from sea life completely blocking a cooling water flow path.
Fouling removal is needed to de contaminate the affected system and allow a restart and the steps can vary depending on the fouling to be removed.