The effect of aeration rate on the efficiency of CANON (completely autotrophic nitrogen-removal over nitrite) process was studied to improve total nitrogen removal of ammonium-rich wastewater.With simulated wastewater as influent

two kinds of CANON reactors

which used sponge and modified polyethylene as carriers respectively

were studied in tests.The results showed that total nitrogen removal efficiency and removal load were closely related to aeration rate

the increase of aeration rate would improve total nitrogen removal of CANON reactor when aeration rate was less than the limiting aeration rate.For the CANON reactor which used sponge as carrier

when aeration rate was 35.8 m3·m-3·h-1

the total nitrogen removal efficiency reached the maximum value of 79.48%

and total nitrogen removal load was 2.32 kg·m-3·d-1.When aeration rate was more than the limiting aeration rate

the effect on total nitrogen removal remained stable

because the structure of sponge protected the Anammox bacteria from inhibition by dissolved oxygen.With sponge as carrier

more biomass could be retained in the CANON reactor

especially for Anammox bacteria

which guaranteed the stable operation of the CANON reactor.For the CANON reactor which used modified polyethylene as carrier

when aeration rate was 6.3 m3·m-3·h-1

the total nitrogen removal efficiency reached the maximum value of 77.6%

and totalnitrogen removal load was 1.01 kg·m-3·d-1.When aeration rate was more than the limiting aeration rate

the effect on total nitrogen removal deteriorated because Anammox bacteria were inhibited by dissolved oxygen.Less biomass could be retained

so the reactor was less stable.