NOM Removal by Coagulation

The presence of natural organic matter (NOM) causes various problems in drinking water and drinking water treatment processes, including (1) negative effect on water quality by causing color, taste, and odor problems, (2) increased coagulant and disinfectant doses (which in turn results in increased sludge volumes and production of harmful disinfection by-products), (3) promoted biological growth in distribution system, and (4) increased levels of complexed heavy metals and adsorbed organic pollutants. NOM can be removed from drinking water through the use of several treatment options, of which the most common and economically feasible processes are considered to be coagulation and flocculation followed by sedimentation/flotation and sand filtration. Most of the NOM can be removed by coagulation, although the hydrophobic fraction and high molar mass compounds of NOM are removed more efficiently than hydrophilic fraction and the low molar mass compounds. Thus, enhanced and/or optimized coagulation, as well as new process alternatives for better removal of NOM by coagulation, have been suggested. In this chapter, we present an overview of the recent research dealing with coagulation and flocculation in the removal of NOM from drinking water.