UK HQ Your time

Biofouling Control for Seawater Intakes

Engineering Excellence for Marine Environments

Submerged intake surfaces are colonised within weeks by mussels, barnacles, hydroids and biofilm that restrict flow, raise head loss and accelerate corrosion — unchecked biofouling can cut intake capacity by half. Effective control combines oxidant dosing, antifouling materials and, where needed, UV or thermal treatment, balanced against disinfection-by-product and discharge limits.

0.5–2.0
mg/L Cl₂ residual
50%+
capacity lost if uncontrolled
90/10
Cu-Ni antifouling
Pulse
low-dose option

Control Methods

Layered antifouling strategy

Continuous Chlorination

Low sodium-hypochlorite residual maintained through the intake to suppress settlement and biofilm.

Shock & Pulse Chlorination

Intermittent high-dose or short pulses exploit mussel valve behaviour at a fraction of the total chlorine.

On-Site Electrochlorination

Hypochlorite generated from seawater on site — no bulk chemical storage or delivery.

Copper-Nickel Alloys

90/10 and 70/30 Cu-Ni screens and pipework are inherently antifouling and corrosion resistant.

UV Disinfection

Chemical-free control for environmentally sensitive sites and polishing duty.

Thermal & Mechanical

Periodic heat treatment, pigging and mechanical cleaning of pipelines and screens.

Dosing Regimes

Matched to organism and discharge limits

RegimeTargetWhen Used
Continuous low-dose0.5 – 2.0 mg/L free Cl₂ residualHeavy fouling pressure, warm waters
Intermittent2 – 5 mg/L, a few hours/dayModerate fouling; chemical saving
Shock5 – 10 mg/L, short durationPeriodic knock-down of established growth
Pulse-chlorination<0.5 mg/L in short pulsesMussel control at minimum dose & DBP

Dosing must be balanced against trihalomethane / disinfection-by-product limits and the need to protect downstream membranes — see RO membrane protection and our chemical treatment services.

Related Seawater Intake Topics

Continue across the seawater intake engineering series

Related Equipment & Services

Design your seawater intake

Talk to our marine engineering team about biofouling control and a complete, compliant intake package — survivable, low-fouling and built for decades of service.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.