Ultraviolet disinfection of oil field process water

A method for inactivating Desulfovibrio desulfuricans in a fracturing fluid containing the Desulfovibrio desulfuricans, the method comprising:

• exposing the fracturing fluid containing the Desulfovibrio desulfuricans to a dose of from about 4 mJ/cm2 to about 10 mJ/cm2 of polychromatic ultraviolet radiation, wherein the fracturing fluid comprises water, wherein the polychromatic ultraviolet radiation comprises at least five inactivation wavelength peaks in a range of from about 200 nm to about 400 nm, wherein each of the major inactivation wavelength peaks is characterized by an intensity greater than about 25% of a maximum peak intensity of the plurality of major inactivation wavelength peaks and by a full width half maximum value greater than about 2 nanometers, wherein the dose of polychromatic ultraviolet radiation inactivates the Desulfovibrio desulfuricans, and wherein the fracturing fluid flows substantially unidirectionally from a fracturing fluid source to a wellbore.

A system for inactivating Desulfovibrio desulfuricans in a fracturing fluid containing the Desulfovibrio desulfuricans, the system comprising:

• an ultraviolet radiation chamber in fluid communication with a fracturing fluid source and a wellbore, wherein the fracturing fluid flows substantially unidirectionally from the fracturing fluid source through the ultraviolet radiation chamber to the wellbore;
• and
• at least one medium pressure ultraviolet lamp arranged substantially within the ultraviolet radiation chamber, wherein the medium pressure ultraviolet lamp exposes the fracturing fluid containing the Desulfovibrio desulfuricans to a dose of from about 4 mJ/cm2 to about 10 mJ/cm2 of polychromatic ultraviolet radiation, wherein the polychromatic ultraviolet radiation comprises a plurality of major inactivation wavelength peaks in a range of from about 200 nm to about 400 nm, wherein each of the major inactivation wavelength peaks is characterized by an intensity greater than about 25% a maximum peak intensity of the plurality of major inactivation wavelength peaks and by a full width half maximum value greater than about 2 nanometers, and wherein the dose of polychromatic ultraviolet radiation inactivates the Desulfovibrio desulfuricans.