Molecular Size Distributions of Dissolved Organic Matter

Twelve samples were obtained from a groundwater basin containing significant levels of color caused by the humic constituents of dissolved organic matter (DOM). The DOM present in raw source samples was characterized according to apparent molecular size (AMS) distribution. The resultant AMS distributions - expressed in terms of dissolved organic carbon, UV absorbance, and trihalomethane formation potential - were found to provide insight into potential treatment process applicability. Ozonation showed the most merit for lower-color, lower-AMS sources, whereas coagulation or membrane treatment was more suitable for higher-color, higher-AMS sources. No clear treatment niche (i.e., AMS range) was identified for activated carbon adsorption. It is well known that naturally occurring color is often caused by humic substances. Aquatic humic substances generally account for approximately 50 percent of the dissolved organic matter