Page 13 - 6_TOC in daily practice
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Sum parameter – Total Organic Carbon
Continuous TOC determination on airports
SCA-130-606
Ice and snow on the wings of airplanes method. In this method, the sample is
increase their total weight and have a acidified to convert the carbonates and
negative impact on their aerodynamics. For hydrogen carbonates present in the sample
reasons of safety, airplanes need to be de- to CO 2. The resulting carbon dioxide is
iced just before they are ready for takeoff. subsequently purged using a gas stream
The de-icing agent that is most frequently passed through the sample.
used is a mixture of water, glycol and TOC (Total Organic Carbon) is a measure of
additives. The exact composition depends, the concentration of organically bound carbon
among other things, on the outside and therefore reflects the pollution level of
temperature. organic substances in wastewater.
Depending on the use of the de-icing agent,
the TOC values can fluctuate significantly.
■ Tried and tested and powerful – the
TOC-4200
The TOC-4200 process analyzer is perfectly
designed for this application. The TOC-4200
is a powerful analyser that uses catalytic
combustion at 680 °C. After the analyser has
automatically removed the inorganic carbon,
a sub-quantity is injected onto a hot (680 °C)
After spraying the airplanes, the de-icing platinum catalyst. Here, all organic
agent enters the sewage system where it components present are oxidized to carbon
leads to a significant increase of the organic dioxide. The resulting CO 2 is transported by a
load. Even when the agent used is carrier gas stream to a highly sensitive and
biodegradable, the effluents must be CO 2 selective NDIR detector, where it is
subjected to a controlled treatment process. measured. The TOC concentration is
For the airport operator, it is therefore calculated using an external calibration.
important to know the organic load of the
airport’s wastewater. The TOC sum
parameter has been well established as an
assessment parameter for wastewater
analysis.
■ Continuous online NPOC monitoring
Important for TOC determination is the
differentiation between organic and inorganic
carbon. Carbonates and hydrogen
carbonates are, after all, present in all natural
waters. The most widely used method for
TOC determination is the so-called NPOC
