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.