Bioremediation, absorbents, skimmers and dispersants: what each one does

Absorbents

Materials that soak up hydrocarbon on contact: booms, pads, rolls. They work well on open surfaces and are cheap to deploy. The problem comes afterwards: a saturated absorbent is hazardous waste that has to be removed, stored and handed to a licensed operator. The more you clean, the more waste you create.

Skimmers

Mechanical equipment that separates the oily layer from the surface and pumps it into a tank. They are the best option where there is volume and open water. They need draught, access and room to manoeuvre, so in the corners of a port they lose almost all their effectiveness. And recovered hydrocarbon is still hydrocarbon: it ends up in a tank that also has to be managed.

Dispersants

Chemicals that break the slick into droplets so it spreads through the water column. The surface looks clean, but the hydrocarbon has not gone: it has been diluted. Their use is regulated for precisely that reason, and in enclosed port waters they are rarely the right choice.

Bioremediation

Microorganisms that consume the hydrocarbon and turn it into CO₂ and water. It leaves no secondary waste because it does not move the pollutant, it destroys it. Being applied as a liquid, it reaches breakwaters, gaps between piles and dock walls. In exchange, it is not instant: it needs one to two days.

The practical conclusion

No method wins at everything, which is why the ports that handle this best do not choose: they combine. The skimmer for volume in open water, the boom to contain, and bioremediation for what is left and for the zones the rest cannot enter.