Biofouling is generally controlled by the use of additive chemicals, but the cost of using environmentally acceptable additives is rising. Consequently there is an interest in alternative methods that do not rely on the use of chemicals. Studies of the different techniques have been made including the use of ultrasound, tube inserts and the circulation of polymer fibres. The results of all three methods of control show considerable promise but further development work is required to optimize the variables and demonstrate cost effectiveness.