Israeli scientists say that ultraviolet light may be a better treatment than strong-smelling chlorine to keep water free of bacteria.

A team of researchers at Tel Aviv University (TAU) say that while chlorine keeps water free of micro-organisms and is used by most water treatment plants, it produces carcinogenic byproducts.

The TAU team says it recently determined the optimal UV wavelength that could be used by water treatment plants and large-scale desalination facilities to destroy health-threatening micro-organisms, as well as make the facilities more efficient.

“In our recent study, we’ve shown how this treatment can be optimized to kill free-swimming bacteria in the water – the kinds that also stick inside water distribution pipes and clog filters in desalination plants by producing bacterial biofilms,” says doctoral student Anat Lakretz, a member of the team.

“The best way to control and kill these micro-organisms is to damage their DNA,” Lakretz says, adding that “The damage that the UV light causes has no known negative effect on the water.”

The scientists note their approach is even more helpful against parasites that aren’t adversely affected by chlorine treatment but place children, the elderly and those in developing nations at particular risk.

They also say that small amounts of chlorine or other oxidants will still be necessary to make sure residual bacteria don’t enter the water further along the distribution pipeline.