Nitrification in Powdered‐Activated Carbon‐Activated Sludge Process

Abstract

Powdered activated carbon (PAC) has been added to activated sludge processes over the past 10 years to improve process performance in a variety of ways, including ammonia removal. Improved ammonia removal is a surprising benefit of PAC since it is not adsorbed. Investigators have speculated that PAC adsorbs inhibitory compounds or provides a media for nitrifier growth. To ascertain the mechanism of nitrification enhancement, a series of experiments were performed with adsorbable (aniline, phenol) and nonadsorbable (ethanol) inhibitors. Experimental results show that adsorption of nitrification inhibitors can dramatically improve nitrification rates in unacclimated activated sludge cultures.