Nitrogen removal from wastewater using a hybrid membrane-biofilm process: pilot-scale studies.

The hybrid membrane biofilm process (HMBP) is a new approach to achieving total nitrogen removal from wastewater. Air-filled, hollow-fiber membranes are placed into an activated sludge basin and bulk aeration is suppressed. A nitrifying biofilm develops on the membranes, exporting nitrate and nitrite to the bulk liquid.