ENDRESS+HAUSER  CA80CR-AAAF1C101

Integrated controller with up to 2 measuring channels and digital Memosens technology

Application

• Optimizing cleaning performance in industrial wastewater treatment plants
• Monitoring of drinking water
• Monitoring of membrane filtration systems
• Monitoring of limit values for the discharge of industrial wastewater

Your benefits

• Easy upgrade to measuring station by connecting with up to four Memosens sensors
• Automatic calibration and cleaning
• Low maintenance costs thanks to long reagent life
• Digital communication for remote access
• Two-channel device available
• Digital fieldbuses (Profibus DP, Modbus TCP, Modbus RS485 and Ethernet IP) and web server

Colorimetric measuring principle

After application-specific sample preparation, some of the permeate is pumped into the mixing/ reaction chamber. The specific color reagent is metered exactly in a defined mixture ratio. The chemical reaction causes the characteristic change in the color of the sample. The multispectral photometer measures the level of absorption by the sample or the stain solution at defined wavelengths. The analyzed wavelengths, and their relationships to one another, are parameter- specific.

Based on proportionality the amount of light absorption is a direct indicator of the concentration of the parameter under analysis in the sample. To compensate for any interference influences resulting from turbidity and fouling, as well as from the deterioration and aging of the LEDs, a reference measurement is performed before the actual measurement. This reference signal is subtracted from the measuring signal. The temperature in the photometer is kept constant to ensure a reproducible reaction that takes place with a short period of time.

Chromium and chromate

Chromium occurs in different oxidation states, of which only the trivalent (Cr 3+ ) and the hexavalent (chromate, CrO 42- and dichromate, Cr 2 O 72- ) are of significance in process applications. While Cr(VI) is recognized as a carcinogen, Cr(III) is only slightly toxic and is an essential trace element in protein synthesis. National standards stipulate limit values for chromate concentration. The German drinking water ordinance, for example, stipulates a limit value for total chromium of 50 μg/l. Separate standards apply to industrial wastewater. The current limit value for tanneries is 2 mg/l, and for electroplating plants the limit value is 0.1 mg/l.