REMOVAL OF DISSOLVED ORGANIC-CARBON BY COAGULATION AND ADSORPTION FROM POLLUTED SOURCE WATER IN SOUTHERN TAIWAN

The removal of dissolved organic carbon from a polluted water source i n southern Taiwan by coagulation and powder activated carbon (PAC) ads orption was investigated in light of increasing concern for the produc tion of potentially toxic chlorinated organic products. The results of this study clearly indicated that the effects of coagulation and PAC adsorption on the removal of nonpurgeable dissolved organic carbon (NP DOC) from Tungkang River water were complementary. Coagulation by alum inum sulfate (alum) or polydiallyldimethylammonium chloride (PDDAC) al one removed only about 40% NPDOC; this type of NPDOC being preferentia lly large organic molecules with negatively charged functional groups. On the other hand, at a 20- to 30-min contact time, PAC removed about 60% NPDOC, mostly low molecular weight and uncharged NPDOC. A total 9 0% removal of NPDOC from this polluted source water was achieved by a combined coagulation and PAC adsorption process. (C) 1998 Elsevier Sci ence Ltd.