the pure aqua uvc-100 system virtually eliminates microbiological contaminants without using potentially hazardous chemicals. Water enters through the bottom port of the ultraviolet generator cell and swirls around a low pressure mercury vapor lamp, which emits powerful ultraviolet light energy at 235. 7 nm wave length. Bacteria, viruses and other microbiological organisms absorb the light energy; which disrupts their dna, and are destroyed safely inside a factory tested stainless steel cell. The treated water then exits through the top port of the cell and is ready for consumption, nothing has been added to your water except cleansing ultraviolet light.