EPA-OGWDW/TSC: 334.0: Residual Chlorine in Drinking Water Using an On-Line Chlorine Analyzer
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Official Method Name
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Determination of Residual Chlorine in Drinking Water Using an On-Line Chlorine Analyzer |
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Current Revision
| Version 1.0 September 2009 |
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Media
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WATER |
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Instrumentation
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Acoustic Velocity Meter |
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Method Subcategory
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Inorganic |
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Method Source
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Citation
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Steven C. Wendelken, Derek E. Losh, and Patricia S. Fair, 2009, METHOD 334.0: DETERMINATION OF RESIDUAL CHLORINE IN DRINKING WATER USING AN ON-LINE CHLORINE ANALYZER: EPA Office of Water, EPA 815-B-09-013. |
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Brief Method Summary
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An on-line chlorine analyzer is used to continuously monitor the chlorine concentration at a drinking water sample point. The instrument is calibrated using aqueous standards or the results from paired grab samples that are collected at the same sample point and time. The grab samples are analyzed for chlorine (free or total) using a method that is approved for drinking water compliance monitoring. The on-line analyzer accuracy is periodically verified/adjusted based on results from grab sample analyses. |
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Scope and Application
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This method is for the analysis of residual chlorine (free or total) in drinking water. It is primarily intended to be used by drinking water utilities for compliance with daily monitoring requirements. This method allows the use of any type of on-line chlorine analyzer (e.g., amperometric, DPD, etc.) for compliance monitoring when used in conjunction with a grab sample reference method that is approved for drinking water compliance monitoring. This method is intended to be used when chlorine residuals (free or total) are in the range of 0.2 mg/L to 4 mg/L.The grab sample reference method must be listed in the methods table of the regulation under which the monitoring is being conducted. (A method in Appendix A may be used if it is listed as approved for the regulation.) |
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Applicable Concentration Range
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This method is intended to be used when chlorine residuals (free or total) are in the range of 0.2 mg/L to 4 mg/L. |
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Interferences
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Organic contaminants and high concentrations of monochloramine may produce false free chlorine readings in colorimetric methods. Colorimetric methods specify procedures to reduce interferences from copper, chromate, and reduced manganese. Strong oxidizing agents (e.g., permanganate, ozone) interfere with free chlorine measurements in all methods. A general discussion of potential interferences to the grab sample measurements is included in Standard Method 4500-Cl A. |
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Quality Control Requirements
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The full initial demonstration of capability must be conducted prior to using the analyzer for compliance monitoring measurements. Routine calibration checks for the grab sample method and for the on-line chlorine analyzer. |
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Sample Handling
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Exposure to sunlight or strong light will cause loss of chlorine. |
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Maximum Holding Time
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Begin analysis immediately after sample collection. Do not store samples. |
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Relative Cost
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Unknown |
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Sample Preparation Methods
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