Effect of pre-sonication on removal of organic matters resulting from chlorinated humic acids

Humic acids are amorphous organic macromolecules that are responsible for the color of natural water. They play an important role in the formation of disinfection by-products, the stabilization of wastewater sludge, and the treatment of wastewater. An ultrasonic process is applied as a pretreatment method for the purpose of reducing the risk of chlorinated by-products. Experimental results indicate that the initial pH, ionic strength, and chlorine demand affect the amount of total organic carbon removal and Cl-2 consumption significantly. The formation of chlorinated by-products depends on both the initial pH and ionic strength. Experimental results also propose a good agreement that the humic acid can be removed efficiently by ultrasonic pretreatment under aerobic conditions. In this study, when the ultrasound/O-2 process is used as a pretreatment method, the biodegradability which is defined as the formation bf BOD5 increases with sonication time. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.