Free Chlorine
Why Test Free chlorine concentrations are tracked at several process points in the treatment system. Check the free chlorine level to provide maximum disinfection efficiency, to maintain adequate levels for CT credits and to deliver the desired free chlorine residual at the Point-of-Entry to the distribution system. Select the DPD Free Chlorine method that adequately covers the expected chlorine concentration and gives the test sensitivity and concentration resolution desired. The method required may change depending upon the test site within the treatment system. The titration methods are easily adapted to meet the test ranges required in a free chlorine treatment process.
Interference-free Free Chlorine
Why Test Use the interference-free indophenol free chlorine method to study the disappearance of free chlorine in reaction rate and chloramination process optimization studies without interference from monochloramine.
Iron
Why Test Residual iron is checked to monitor the effectiveness of the chlorine oxidation processes used to remove iron. Use the FerroVer Iron colorimetric method for routine testing. Use the TPTZ Iron colorimetric method when low-level iron testing is required.
Manganese
Why Test In addition to causing operational and aesthetic problems, manganese causes a false positive value in standard DPD Total Chlorine determinations. The positive interference cannot be readily identified in the DPD total chlorine determination. The presence of manganese must be separately analyzed to determine if sample pretreatment is required to compensate for the manganese interference. Test also to check the effectiveness of the manganese removal processes.
pH
Why TestMonitor pH to maintain a reasonably steady pH value and to control process efficiency. While pH levels may be unique to a specific potable water treatment process, water being disinfected with free chlorine in a pH range of 7.0 to 7.5 has been found to be most effective. The pH value is also used in determining CT credits.
Method |
Use Model |
Product |
Electrochemistry - Direct Read |
Lab |
HQd Benchtop with pH Ultra, pH refillable, or pH gel probes> |
Electrochemistry - Direct Read |
Portable |
HQd Portable with pH Ultra, pH refillable, or pH gel probes |
Electrochemistry - Direct Read |
On-line |
Digital pHd sc with sc200/sc1000 |
Hypochlorite
Why Test Bulk hypochlorite (bleach) solutions are unstable and the chlorine concentration will decrease during transportation or during storage. Delivered solutions are billed based on the % or g/L chlorine concentration delivered to the facility or end-user. The chlorine concentration is checked upon delivery to insure accurate billing. Storage tanks are periodically checked to maintain optimum chlorine feed pump rates. Test methods designed to measure % or g/L chlorine concentrations directly without dilution should be used.