BROMATE DESTRUCTION BY UV IRRADIATION AND ELECTRIC-ARC DISCHARGE

Bromate ion destruction by UV irradiation using either a low pressure mercury lamp or a medium pressure mercury lamp has been evaluated. A l ow pressure lamp which emits radiation predominantly at < 200 nm was m ore effective than the UV lamp which emits radiation at 254 nm, since bromate ion has a peak absorbance of about 195 nm. Bromate ion was sho wn to be reduced to bromide ion with bromine as an intermediate. Broma te ion destruction using a low pressure mercury lamp (< 200 nm) ranged from 3 to 38% for doses ranging from 23 to 228 mW-s/cm(2); 7-46% dest ruction was achieved using a medium pressure lamp with initial bromate ion concentrations of 11-38 mu g/L and doses ranging from 60 to 550 m W-s/cm(2). A new innovative electric are discharge method also has bee n evaluated and compared with UV irradiation. The electric are dischar ge method destroyed 12-45% bromate ion for doses ranging from 130 to 1 300 mW-s/cm(2).