Vacuum-UV radiation at 185 nm in water treatment – A review

•A comprehensive review on VUV irradiation in water treatment is given.•VUV radiation of water results in the in situ generation of hydroxyl radicals.•Ozone can be generated by VUV radiation of oxygen and air.•Irradiation at 185 and 254 nm offers organic contaminant control and disinfection.•VUV irradiation provides many opportunities for future water treatment.

The vacuum-UV radiation of water results in the in situ generation of hydroxyl radicals. Low-pressure mercury vapor lamps which emit at 185 nm are potential sources of VUV radiation. The scope of this article is to give an overview of the application of VUV radiation at 185 nm for water treatment including the transformation of inorganic and organic water constituents, and the disinfection efficiency. Another focus is on the generation of ozone by VUV radiation from oxygen or air and the application of the produced ozone in combination with VUV irradiation of water in the VUV/O3 process. The advantages and limitation of the VUV process at 185 nm as well as possible applications in water treatment are outlined.