Disinfection By-Product Formation in Drinking Water Treated with Chlorine Following

I hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii As far back as the early 1900’s when it was discovered that water could be a mode of transmitting diseases, chlorine was used to disinfect water. In the 1970’s, the formation of disinfection by-products (DBPs) from the reaction of chlorine with natural organic matter was discovered. Since then there have been various studies on alternative disinfectants that could inactivate microorganisms and at the same time form less or no disinfection by-products. More recently the ultraviolet (UV) irradiation has been used to both disinfect and remove organic contaminants in drinking water. Though the use of UV irradiation has been found to be very effective in the inactivation of microorganisms, it does not provide a residual effect to maintain the water’s microbial quality in the distribution system. Due to this,

Articles N ( 2 D) Product Velocity Mapped Imaging in the VUV Photolysis of Nitrous Oxide at 118.2 nm

this paper we present results for the VUV photodissociation of N 2 O at 118.2 nm, which is nearly resonant with the transition (3pp 2p) to a Rydberg state. The VUV radiation was produced by non-resonantly tripling 354.6 nm laser light in a rare gas cell. We detect the N( D 5/2 ) product following the primary VUV photolysis: N 2 O +118.2 nm N( using the velocity-mapped, ion imaging technique. The focused ionization laser produces a background of N( D 5/2 ) atoms by a two-photon process: N 2 O +2 (268.9 nm) N( which contributes to the image. A third process produces a background of N signal in a multi-photon process involving the 118.2 nm light, and possibly the 354.6 nm laser light: N 2 O +118.2 nm/354.6 nm N + NO(X) (3) By making use of the spatial properties of the imaging technique, we were able to distinguish the primary process of interest from the background contribution