Attached Growth Reactor for Bod Removal and Nitrification with Polyurethane Foam Medium

Ammonium nitrogen is a principal material of concern in treated water discharge. Applicability of completely mixed series reactor with Polyurethane foam cubes as attached medium to municipal sewage treatment for BOD removal and nitrification was experimentally examined. Nitrifier grew preferably on the polyurethane foam cubes, and its nitrifying activity reached 0.33 (mg N/hr·cube) for the cubes of 8 cm . BOD removal was completed in 4 hours, and then nitrification began to occur and was completedin 10hours under the condition of temperature as low as 15 degrees centigrade. The heterotrophic bacteria and nitrifier grew separately in the different cells of the reactor. Nitrification activity was inhibited by some organics included in the influent. The effect of inhibition was severer with increasing DOC.