Anammox in “zeolite-anammox” refers to a bacterial cocktail containing: anammox, nitrifiers, and denitrifiers
Anammox is short for “anaerobic ammonium oxidation”. Anammox bacteria derive their energy from eating NH4. They combine ammonium (NH4+) with nitrite (NO2-) to form nitrogen gas:
NH4 + NO2 = N2 + 2H2O.
The influent contains NH4+; we get NO2- from:
1) First stage of nitrification using symbiosis between nitrifiers and anammox (NH4+ → NO2- → NO3-). Consumption of oxygen for oxidation of ammonium helps keep conditions anaerobic for anammox as well.
2) Partial oxidation of NH4+ to NO2- by anammox themselves (anammox are also capable of dissimilatory reduction of nitrate to nitrite or ammonia (DNRA).
•HALF – needs half the infrastructure.
•HALF – uses half the air.
•HALF – produces half the greenhouse gas.
•Needs high NH4 concentrations.
•Needs high temperatures.
Anammox bacteria were discovered in the 1990’s in a WWTP in Holland. The first full-scale anammox reactor in the USA has recently been completed at Hampton Roads on the East Coast.