Meet EPA regulations with continuous Total Chlorine Measurement0 pages

Application Data Sheet
ADS 4950-05/rev.E
January 2009

Water and Wastewater Industry

Continuous Total Chlorine Measurement
and Recording to Meet E.P.A. Discharge
Requirements
BACKGROUND
E.P.A. regulations require those who discharge chlorine to
provide a continuous record of total effluent containing chlorine concentration at the outfall to prove that the discharge
concentration does not exceed their allowable limit. To meet
these requirements the following criteria must be met:
1.

The instrument system must be reliable. It must perform for long periods of time before recalibration
becomes necessary.

2.

Accurate low level measurement with the capability to
monitor down to 500 ppb full scale is necessary in many
cases.

INSTRUMENTATION
Total chlorine can be determined using the Rosemount
Model TCL. This system is a sample conditioning and mea-

suring system for the continuous determination of total
chlorine in water. The conditioning system continuously
pumps buffered potassium iodide reagent into the sample.
Free and combined chlorine (total chlorine) react with
potassium iodide to form an equivalent amount of iodine.
An amperometric sensor measures the concentration of
iodine and sends its signal to the Rosemount Dual Input
Analyzer Solu Comp II Model 1056. The analyzer displays
the concentration of total chlorine. Additional choices in
instrumentation include two-wire transmitters Model Xmt
and Model 5081.
The Sample Conditioning System should be located near
the final outfall point. A simple overflow weir maintians the
correct flow rate into the low flow cell, and sends any
excess sample to drain. The Analyzer (NEMA 4X enclosure) is field mountable and provides multiple outputs for
recording and controlling. Figure 1 illustrates this process
from water intake to discharge.

INSTRUMENTATION: Total Chlorine Measurement
Model TCL Sample Conditioning System
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NO METAL WETTED PARTS. Ideal for seawater
LOW SAMPLE FLOW (about 15 mL/minute) means little waste
REAGENT-BASED SYSTEM measures true total chlorine
FIVE GALLONS OF REAGENT lasts two months

Model 1056-24 Chlorine Analyzer (shown)
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LARGE, BACK-LIT DISPLAY with easy to use interface.
TWO INDEPENDENT OUTPUTS
THREE FULLY PROGRAMMABLE ALARMS
INPUT FILTER improves stability at low concentrations

Model 499A CL-02 Sensor
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MEMBRANE-COVERED AMPEROMETRIC SENSOR
NO TOOLS REQUIRED to change membrane
MAINTENANCE TAKES ONLY A FEW MINUTES a month
VARIOPOL CONNECTOR OPTION allows the sensor to be replaced without
removing and rewiring cable