To promote the engineering applications of anaerobic ammonium oxidation (ANAMMOX) for sewage treatment

nitrogen removal rate and key operational parameters were studied in two typical filters with ceramsite or volcanic rock as filter media were studied. The obtained results showed that the anammox biofim in both biofilters was successfully cultivated after 10 days of inoculation. Filter media and backwash both played important role in achieving stable anammox in biofilter. At low filtration velocity

in both biofilter

not only nitrogen removal rate was almost similar

but also water backwash and long backwash cycle were optimal. However

at high filtration velocity

volcanic rock biofilter was more easily blocked up than ceramsite biofilter. The effective depth of filter layer in volcanic rock biofilter was also thinner than that in ceramsite biofilter. Besides

air+water backwash style was optimal

backwash cycle should be shortened and backwash time should be prolonged. Filtration velocity in both biofilters should be controlled lower than 2 m·h-1. The highest nitrogen removal loading rate in volcanic rock biofilter and ceramsite biofilter were 3.81 kg·m-3·d-1 and 3.56 kg·m-3·d-1

respectively.