Behavior of autotrophic denitrification and heterotrophic denitrification in an intensified biofilm-electrode reactor for nitrate-contaminated drinking water treatment

► Intensified biofilm-electrode reactor using cooperative denitrification was developed. ► Cathode was embedded in the fiber carriers in the reactor. ► The behavior of AD and HD in the reactor was respectively evaluated. ► Cooperative effect of the AD and HD processes was observed. ► The superiority of the HAD over single AD and HD was proved.