Enhancement of nitrogen removal in a novel anammox reactor packed with Fe electrode

► The positive effect of Fe electrode in anammox reactor enhanced nitrogen removal significantly. ► Fe-electrode reaction created a favorable environment for the growth of anammox bacteria. ► Fe-electrode anammox reactor (R1) is reliable and useful for enriching anammox bacterium. ► Planctomycete KSU-1 was identified as the dominant anammox bacteria in R1.