Any concise and clear explanation of how does high temperature affect/inhibit NOB?
Low DO with intermittent aeration, high temperature, high salt concentration, high ammonium concentration, high nitrite/nitrous acid are all factors limiting the growth of NOB. How does high temperature inhibit NOB growth?
Thanks in advance.
Kulthoum
Because every biological process has its temperature maximum.
Best regards
Vit
check these links
https://books.google.ca/books?id=SV5XDQAAQBAJ&pg=PA299&lpg=PA299&dq=Why+does+high+temperature+suppress/inhibit+nitrite+oxidation+process?&source=bl&ots=lvOpu3sDTH&sig=eyGBu-HcnNSyFBmzmjrrMczPRfg&hl=en&sa=X&ved=0ahUKEwi4sozis9HTAhVo44MKHRr1BCYQ6AEILTAC#v=onepage&q=Why%20does%20high%20temperature%20suppress%2Finhibit%20nitrite%20oxidation%20process%3F&f=false
Dear Ismail,
it depends on what you mean with "high" temperature?
e.g. at 30-35°C, it is not the temperature that inhibits NOB, but the specific growth rate of AOB is higher that the growth rate of NOB at 30°C (which is not the case at 15°C); so high temperature (> 30°C) is used together with low slugde age (SRT) to wash out NOB and keep AOB in the reactor. this is the principle applied in the SHARON process.
greetings, jan
Jan's answer is excellent!
Many operators ignore the impact of temperature on substrate conversion and on the specific growth rates of various micro-organisms.
Similar cases in anaerobic digestion.
Dear Kulthoum,
The optimum temperature range for growth of nitrification bacteria is about 28-30 centigrade. The growth rate starts to decrease after this temperature intervals. All microorganisms have a tolerance interval against each environmental factor.
Dear Kulthoum Ismail,
I agree with Jan Dries.
Probably the phrase "high temperature suppress/inhibit nitrite oxidation process" is a "poetic license" or "language license" when we want to summarize the factors applied in order to achieve the partial nitrification (favor AOB versus NOB). 30 ºC is not really inhibiting the NOB, but AOB are more favored than NOB in this conditions, so nitrite can be accumulated if we apply a high selection pressure.
Isaka proposed a "real" NOB inhibition by applying high temperatures. A heat-shock temperature selection to avoid NOB growth in gel carriers in a partial nitrification process. They found that AOB survive to heat-shock treatments at 90 °C for 1 h, while NOB were dead at 60 ºC when polyethylene glycol gel carriers were used to grow nitritation populations.
Regards
Nico
Article Novel nitritation process using heat-shocked nitrifying bact...
Dear Dr Nicolas,
The paper looks interesting , thank you for sharing it.
Kulthoum
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