Evaluation of an Inactivation Procedure for Determining the Sorption of Organic Compounds to Activated Sludge

Abstract A batch method was developed and validated for determining the sorption coefficient ( K d ) of biodegradable organic compounds to activated sludge solids using a nonspecific analytical technique, total organic carbon (TOC) analysis. In this method, activated sludge solids were first inactivated by lyophilization and dry heat (103°C) and then washed to remove any dissolved organic carbon released during the inactivation procedure. The inactivated sludge solids were exposed to a range of concentrations of different test compounds in synthetic wastewater until equilibrium was achieved ( K d values) for four detergent chemicals in inactivated sludge solids using TOC analysis were in good agreement with values determined in fresh activated sludge using radiolabeled materials. These K d values are suitable for use in estimating environmental exposure concentrations and for developing screening-level models to assess the removal of organic compounds by sorption and settling during activated sludge wastewater treatment.