Engineering Evaluation Case: A Seawater Scrubber Loses Capacity Because Marine Biofouling Develops in Low-Flow Areas
Seawater can provide an attractive scrubbing liquid because it is readily available at coastal or marine sites.
It also contains biological organisms and nutrients.
A tower that is chemically stable can gradually lose hydraulic capacity because biological material grows in:
- low-flow piping;
- distributor branches;
- packing;
- drains.
Project Situation
Consider a seawater packed scrubber.
Chemical analysis shows:
- acceptable salinity;
- sufficient alkalinity.
Yet over months of warm operation:
- pressure drop increases;
- liquid distribution becomes less uniform;
- slime appears on internal surfaces.
The limitation is biological rather than purely chemical.
Biofouling Prefers Low-Velocity Zones
High-flow pipes may remain relatively clean while:
- dead legs;
- distributor corners;
- support pockets
accumulate slime and biological growth.
This makes the fouling pattern highly nonuniform.
Packing Provides Protected Surface Area
The same surface area that helps mass transfer can also provide attachment points for:
- microorganisms;
- biofilm.
Fine packing can therefore lose open area progressively.
Intermittent Operation Can Increase Risk
A continuously flushed system may behave differently from a scrubber that:
- stops overnight;
- remains full of warm seawater.
Stagnant periods can encourage biological growth and settlement.
Biofilm Captures Mineral Solids
Once biofilm forms, it can trap:
- silt;
- shell fragments;
- precipitated salts.
The final deposit may become a mixture of biological and inorganic material.
Cleaning Strategy Must Be Planned
The plant may use appropriate:
- flushing;
- water treatment;
- biocide strategy
according to environmental and process requirements.
The internals should be compatible with the selected maintenance chemistry.
Engineering Takeaway
Seawater chemistry can be acceptable while seawater biology becomes the controlling maintenance problem.