Chlorine Analyzer Helps Determine Appropriate Disinfectant Dosing

Many utilities find it useful to go beyond basic requirements for monitoring free chlorine residual. Monitoring the free chlorine, monochloramine and total chlorine provides the operator with a more complete picture with which to determine his or her control of the disinfection process. This allows the operator to rapidly identify changes in water quality that may impact taste and odor.

In addition, precise and accurate measurement of the used primary disinfectant and its byproducts (DBPs) is an increasing concern. As the disinfection strength depends on pH, it must be measured. Correct measuring equipment for the disinfectant is fundamental for the process and allows correct dosing with fewer chemicals DBPs.

The Swan AMI Codes II CC is a versatile colorimetric analyzer that can measure free chlorine, monochloramines and total chlorine, in addition to combined chlorine and pH. The product uses the proven colorimetric method for chlorine monitoring using N,N-diethylp-phenylenediamine (DPD), which reacts with chlorine when buffered at the appropriate pH to form a magenta color, the intensity of which is proportional to the chlorine concentration. The reaction occurs in 3 to 5 seconds. TC1 is determined by the addition of the pH buffer, DPD and potassium iodide; again, the reaction occurs in 3 to 5 seconds. After TC1 is determined, the reaction is allowed to continue for a total time of 2 minutes, when TC2 or the total residual chlorine is determined.

A simple 4-20mA output used with SCADA provides the certainty of a correct ammonia feed. The complete system comes pre-mounted on panel, ready for operation. Ammonia measurement or other additional instruments are not necessary but can be provided for added confidence in the treatment process.