In contrast to the standard BOD5 method the BioMonitor measures the total BOD. In the BOD5 measurement nitrification inhibitors are added to the sample, which suppress the degradation of nitrogen compounds. This results in the determination of the degradation of carbon compounds (carbonaceous-BOD) only and the nitrification part is not considered in BOD5 measurements.
As a waste water treatment plant can be reliably controlled and monitored only by the determination of total BOD, the BOD5 is insufficient for this purpose.
Alternatively to the BOD5 measurement LAR AG provides an online respirometer, which operates like a miniature waste water treatment plant: The BioMonitor.
The BOD analyzer degrates nitrogen and carbon compounds in special waste water cascades, so that the meaningful total BOD can be determined within 4 minutes.