Microwaves 'cook ballast aliens'
US researchers say they have developed an effective way to kill unwanted plants and animals that hitch a ride in the ballast waters of cargo vessels.
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Co-author Dorin Boldor, from Louisiana State University’s Agricultural Center, said the team envisaged the microwave device being fitted to the exit valve of a ballast tank.
"The basic idea is that you take the ballast water and pump it through a microwave cavity."
He added that the system would follow the same principle as a household microwave oven.
"The power level is much higher and a different frequency, but it creates a very high intensity electric field in the centre of the cavity that oscillates rapidly.
"The water molecules are going to start spinning around very fast and they are going to create a lot of friction that generates heat," Dr Boldor explained.
"But it generates heat in the whole volume at the same time, unlike if you try to use another heating mechanism where you have to take the heat from somewhere else and conduct it through the liquid."
This means that the researchers have a high degree of confidence that the system is treating all of the water to remove the unwanted organisms.
"It is extremely fast and very efficient at transferring the energy from the microwaves into heat," he told BBC News.