Natural Organic Matter (NOM)

Natural organic matter (NOM) is an organic material from environmental origin and produced by biodegradation of organic substances (plants, etc.). NOM gives surface waters a brownish color and is a problem in drinking water supply, not because of its toxicity but because some of its components can react with chlorine used as disinfectant. The reaction by-products include trihalomethane, haloacetic acids, chlorophenols, etc. which are potentially carcinogenic. The NOM components are known as trihalomethane precursors (THMPs), and it is recognized that their removal prior to disinfection is important for public health. Membrane technology is frequently used for treatment to remove NOM from surface waters (see Natural Organic Matter, Removal and Fouling of).

Natural organic matter (NOM) has a broad spectrum of molecular weights and size distributions, functional groups, and substructures. The term NOM covers the particulate colloids (POM), “dissolved” colloids, and macrosolutes or...