【国外标准】 Standard Test Method for the Continuous Measurement of Dissolved Ozone in Low Conductivity Water

5.1 Dissolved Ozone is useful in many industries for water sanitization, TOC reduction, food preservation, cleaning-in-place of food and beverage systems, and pyrogen destruction. It is often necessary to know how much ozone has entered the water, how much remains, and the degree to which it has been removed before process use.5.2 Some applications require that contact time, DO3 concentration integrated over time, be calculated, to assure disinfection.5.3 Continuous observation of trends in these measurements are needed for continuous quality monitoring and the measurement may be used for closed loop control of ozonation.5.4 In many pure water applications and especially where water quality is regulated by the FDA or similar enforcement agencies, ozone removal must be complete before the water is used. This test method is useful for detecting and determining dissolved ozone levels in water at the trace level as well as at process concentrations where sanitization and chemical reactions occur.1.1 This test method covers the on-line and in-line determination of dissolved ozone (DO3) in low conductivity water in the range from 0.001 mg/L to 5.0 mg/L DO3 and conductivity <100 μS/cm, typical of pharmaceutical and microelectronics pure waters. DO3 is detected by correlating the response of a membrane-covered electrochemical sensor to the dissolved ozone concentration.1.2 This test method provides a more convenient means for continuous measurement than the colorimetric methods typically used for grab sample measurements.1.3 This test method has the advantage of high sensitivity as well as durability in the process environment and has few interferences.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.