Effects of wavelength and water quality on photodegradation of N-Nitrosodimethylamine (NDMA)

► Two new lamps were compared with a 254-nm low pressure mercury UV lamp for photo-degradation of NDMA. ► A 222-nm Kr Cl Excimer UV lamp, and a 230- to 270-nm filtered medium pressure mercury UV lamp were used. ► The 222-nm lamp and FMP lamp achieved 4 and 2.8 times higher degradation efficiency. ► The 222-nm lamp was strongly affected by UV-absorbing compounds in the water. ► The FMP lamp showed more stable degradation efficiency than the 222-nm lamp.