AWWA JAW17270

The work described in this article investigated the effects of conventional treatment by alum coagulation and lime softening on the direct removal of the total organic carbon (TOC) associated with humic substances of different origins and on the subsequent adsorption of residual TOC by activated carbon. One commercial humic acid, one commercial fulvic acid, and humic acid present in the raw water supply (Huron River) of the city of Ann Arbor, Michigan, were selected for study. The results of the study indicated that alum coagulation and lime softening exhibit variable effectiveness for removing the TOC associated with humic substances in water supplies. This variability relates primarily to differences in the sources and types of humic matter. Both alum and lime treatment result in humic residuals that manifest different adsorption characteristics than those present in the same waters prior to chemical pretreatment. ; Includes 6 references, tables, figures.