Development of New Nitrogen Removal System Using Nitrifying Bacteria Immobilized in Synthetic Resin Pellets

Abstract

A newly developed process applying a technique of microorganism immobilization to biological nitrogen removal is reported. Nitrifiers immobilized in 2 to 3 mm diameter polyethylene-glycol resin (Nitrifying pellets) are mixed with activated sludge in the nitrification tanks to promote quick nitrification. Due to the high nitrifying activity of the pellets, nitrification of municipal wastewaters is completed within a few hours. This paper introduces the synthetic polymer and immobilization method suited to nitrifiers, the conditions for pellet fluidization, the activity of nitrifying pellets and its treatment performance as a nitrogen removal process.