Patent ID: 8877068

Claim:
A pre-treatment method for ultraviolet light disinfection of water streams having suspended solids in a liquid fraction using ultraviolet light irradiation from a uv light bank with uv light tubes, comprising: a. injecting sulfur dioxide (SO 2 ) into the water streams before undergoing ultraviolet Eight disinfection at a point before the light tubes to form a sulfurous acid reducing solution, which dissociates to produce hydrogen ions, sulfites, bisulfites and free SO 2 at an acid concentration below that required for disinfection, but sufficient to chemically dewater and agglomerate suspended solids without polymers, acid leach heavy metals from the solids into acidified liquid fractions and reduce bicarbonate levels to reduce alkalinity scaling and iron deposit buildup on the uv light tubes, b. removing and disposing of the suspended solids from the acidified liquid fraction fanning recovered treated water, c. passing the recovered treated water between the light tubes to prevent and remove scaling and prevent solids from adhering to the light tubes to provide sufficient exposure to ultraviolet light for disinfection to produce a disinfected recovered treated wastewater, and d. adjusting the pH of the disinfected recovered treated water for reuse.