Discussion
375
(combined basin) used.
The difficulties which were experienced during our measurement runs, and which we have
mentioned, are those relating to the Respiratory Activity.
The information required is the respiratory activity of microorganisms in their medium
(temperature, DO content, agitation. . .), and not in any type of measuring cell. On the contrary, the
RA measurement in situ implies either hypotheses on the representative character of the measuring
points, or a number of measuring points, and this makes observations during a sampling run
impossible.
As to the measurement of BOD 5 , - which is the most correct way to determine biodegradable
matter, - it may be replaced by such measures as COD but in this case the relation between these
types of measurements and biodegradable matter must be known.