Method and system for providing ultrapure water with flexible lamp configuration

A method of treating water comprising:

• Providing water to be treated;
• Measuring a total organic carbon (TOC) value of the water to be treated;
• Introducing persulfate anions to the water to be treated based in part on at least one input signal of the measured TOC value of the water to be treated;
• Introducing the water containing persulfate anions to a primary reactor;
• Exposing the persulfate anions in the water to ultraviolet light in the reactor to produce an irradiated water stream;
• Providing an electronic ballast circuit including a resonant tank circuit having a power output operatively coupled to the ultraviolet light, the electronic ballast circuit operable to control the continuously variable intensity of the ultraviolet light over a continuous range of power levels by continuously measuring the current supplied to the ultraviolet light and adjusting a frequency of a drive voltage supplied to the resonant tank circuit responsive to at least one input signal from the measured TOC value;
• Wherein the electronic ballast circuit controls the continuously variable intensity of the ultraviolet light to provide sufficient power to the ultraviolet light to remove a desired amount of TOC from fluid undergoing treatment while not producing more ultraviolet radiation than is necessary to remove the desired amount of TOC;
• and
• Adjusting the continuously variable intensity of the ultraviolet light based in part on at least one of an input signal selected from the group consisting of a TOC value of the water to be treated, a persulfate value of the water downstream of the reactor, and a rate of addition of persulfate anions.