Antifouling

The main types of biofouling treatment methods are:

Electrochlorination

Electrochlorination is a method in which chlorine is generated to produce sodium hypochlorite, which is used to prevent fouling. Titanium is used as the cathode material whereas titanium coated with platinum is used as anodes. Chlorine is generated at the anodes along with other elements to form sodium hypochlorite: NaCl + H2O + Energy > NaOCl + H2.

A large amount of hydrogen gas is also produced which must be evacuated in a safe way. The total output of produced chlorine is a function of current, hence the flow has to be ensured to ensure cooling. 10 ppm chlorine in sea water would kill all marine life quickly, whereas 1 ppm will prevent fouling. This system can only be used in seawater.

Electrolytic System

Electrolytic systems are one of the most used system to prevent biofouling. This system is simple and often consists of copper anodes that are placed in the sea chest and when a DC current is applied copper ions are produced. These copper ions in the seawater prevent marine organisms from settling down and multiplying on the surface of the pipes. Adding copper into the ocean is not ecologically friendly, hence other methods might be a better alternative.

Electrolytic systems are often called:

ICAF – Impressed Current Anti Fouling systems, or:
MGPS – Marine Growth Protection System

Chemical Dosing

Chemical dosing is also a common method which is used to prevent marine growth in a piping network. Antifouling chemicals are used to dose sea water boxes.

Ultrasonic System

Ultrasonic systems are said to be one of the most efficient system to prevent biofouling with as much as 80% reduction of marine growth. These systems use a wave generator that sends high frequency electrical pulses to a transducer located in the sea chest. One additional advantage with this system is that it uses no toxic chemicals.