In a set of nitrification of black wastewater experiments, nitrate formation took place despite low levels of alkalinity (lower than 7.14 mg alkainity per mg of NH4-N oxidised. what could be the reason? whether heterotrophic nitrification can take place or autotrophic nitrifiers can work at low levels of alkalinity? Is there any literature available for this kind of case?
Did you observe complete nitrification or only partial? It is not the lack of alkalinity that inhibit nitrification, but the low pH that will occur as the alkalinity is exhausted during the nitrification.
@Henrik rasmus Andersen: Sir, in one set of batch experiments, complete nitrification because at the end of reaction time period 3d, high nitrate formation and intermediate nitrite formation was observed only at less time periods.
Ok. A few questions.
@Henrik rasmus Andersen:
1.Sir, initially pH raised from 7.5 to above 8.2 because of air stripping of ammonia and bicarbonate alkalinity. Then, pH started to drop to near 6.5 as nitrification occurs.(black water from toilets)
2. Mass balance from different sets, 35 -40% N nitrified, 4-8% N remained as ammonium and rest of ammonium lost due to volatilisation plus porous media adsorption. Increase in alkalinity was not observed.
Hello Nitish,
Yes autotrophic anaerobic ammonium oxidizers (anammox) don't consume alkalinity and produce nitrate as a side-product along with nitrogen gas.
There is plenty of scientific literature about anammox conversion.
@Bruno Peeters: yes sir annamox process may not consume much alkalinity. my experiments were performed under aeration condition for high ammonium blackwater.whether annamox process can take place in aerated systems?
@Nitish: Yes anammox uses nitrite NO2- to oxidize ammonium NH4+. This nitrite is produced from the partial oxidation of ammonium with well controlled aeration. We apply single step simultaneous nitritation-denitritation using anammox in various low and high strength wastewaters at full scale since almost 25 years now. In high strength rendering wastewater we achieved over 99% TKN and NH4+/NH3 removal.
Dear Bruno, I am interested in nitrification-denitrification process, can you explain hoe can such one single process (i.e. nitrification-denitrification) can be treated in combination, how can we control aeration requirements for each process ? Should we separate process in tow tanks (aerobic- anaerobic).
Regards
@Bruno Peeters:
I am interested in nitrification-denitrification process, can you explain hoe can such one single process (i.e. nitrification-denitrification) can be treated in combination, how can we control aeration requirements for each process ? Should we separate process in tow tanks (aerobic- anaerobic).
Regards
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