oxitop deals with vacuum produced due to CO2 absorption, through nitrification there is no CO2 production, hence no vacuum
Hello,
I think that BOD measurement using the OxyTop system (respirometric methos) is designed to measure the oxygen that bacteria in the sample consume. Bacteria inhale oxygen and exhale carbon dioxide. But carbon dioxide is reacted with sodium hydroxide, so it won’t contribute to the pressure in the system. The difference in pressure is then given by the consumed oxygen.
But some nitrificants also consume oxygen in the conversion of ammonium to nitrite and then to nitrate. This consumption is not included in the BODn value, so an inhibitor is added to prevent this conversion.
See more in the attached file.
Hope this is useful.
No oxitop does not measure nitrification but oxygen utilization. As a matter of fact nitrification is stopped in Oxitop by the addition of nitrification inhibitor (allylthiourea) as part of the protocol.
oxitop measures all the oxygen consumed, either by degradation of organic matter or by nitrification. With two samples, one with inhibitor and one without it, you can know the oxygen used in nitrification. Maybe it will be possible perform a kinetic study with other additional tests
- Badges
- Science topic