What is the discharge volume and content for the CL17 chlorine analyzer?

Document ID

Document ID TE6881

Published Date

Published Date 27/05/2017
Question
What is the discharge volume and content for the CL17 chlorine analyzer?
Summary
Discharge volume of the waste stream, including the amount of N,N-diethyl-p-phenylenediamine (DPD) reagent, for Free and Total chlorine analyzers. 
 
Answer

The amount of sample going to drain on a CL17 will depend on the sample flow coming into the unit.  If we make the assumption that the sample conditioning kit is used to give us an average sample flow to the CL17 of 300 mL/minute this would give us a daily sample volume of 432 liters (300 mL * 1440 minutes) to this we have to add the reagent consumption, and the CL17 uses 2 reagent solutions with 500 mL volume per month so this could be calculated as approximately 33 mL per day consumption. You can safely use 115 gallons per day as an approximation through the instrument. If the customer were to use the maximum flow rate of 500 mL/min, the volume would be 720 liters or 191 gallons/day.

DPD amounts and concentration in that waste stream varies between Free and Total Chlorine applications:
Free Chlorine CL17 discharges ~0.9 mg of DPD per measurement cycle (~2.5min) or ~ 16 g/month. DPD concentration in the waste stream will depend on the flow rate and will vary from ~0.7 mg/L to 1.8 mg/L for the specified flow rate (200-500 mL/min).
Total Chlorine CL17 discharges ~1.5 mg of DPD per measurement cycle (~2.5 min) or ~ 25 g/month. DPD concentration in the waste stream will depend on the flow rate and will vary from ~1.2 mg/L to 3.0 mg/L for the specified flow rate (200-500 mL/min).
Therefore, on average, DPD concentration in the waste stream is within 0.7 to 3.0 mg/L (ppm).

Please note there is a way to minimize the water volume going to waste.