108
4 Nitrogen and Phosphorous Recovery from Municipal Wastewater …
Fig. 4.2 The DEAMOX
process. Reprinted and
modified with permission
from Elsevier [25]
NH
+
4 + 1.32 NO
−
2 + 0.066 HCO
−
3 →1.02 N 2 + 0.26 NO
−
3
+ 0.066 CH 2 O 0.5 N 0.15 + 2.03 H 2 O Anammox
(4.10)
Denitrifying ammonium oxidation (DEAMOX) is another method based on the
ANAMMOX process. This method does not require separate production of nitrite.
It combines the ANAMMOX reaction with the autotrophic denitrifying conditions
and uses bisulfide as an electron donor to generate nitrite from nitrate [22, 25]. The
Schematic diagram of this process is illustrated in Fig. 4.2.
N − organics + SO
2−
4 → NH
+
4 + HCO
−
3 + CH 4 + HS
−
(4.11)
NH
+
4 + O 2 → NO
−
3 + NO
−
2
(4.12)
4NO
−
3 + HS
−
→ 4NO
−
2 + SO
2−
4
(4.13)
NH
+
4 + NO
−
2 → N 2 + 2H 2 O
(4.14)
The DEAMOX process is only applicable to sulfate-bearing wastewater with a
defined ratio of sulfate/N. As another limitation of the process, in the case of sulfaterich wastewater, all bacterial species (especially ammonia oxidizers and anammox
bacteria) are inhibited by hydrogen sulfide [25].
Completely Autotrophic Nitrogen-removal Over Nitrite (CANON) is a singlestage denitrification process in which aerobic ammonia oxidizers and anaerobic
ammonia oxidizers simultaneously oxidize ammonia to nitrogen gas and a small
amount of nitrate [22, 26].
NH
+
4 + 0.85O 2 → 0.435N 2 + 0.13NO
−
3 + 1.3H 2 O + 1.4H
+
(4.15)
Compared with other methods, the CANON process consumes less oxygen, does
not need external carbon sources and has less N 2 O emissions [27].