The majority of NOM originates from the soils. These aquatic humic substances are mainly derived from decomposing plants and animals and color the water from yellow to brown. They also provide a substrate for bacteria and fungi, that, if not removed during the treatment process, can contribute to excess microbial growth in the water distribution system. This in turn can lead to secondary problems such as disease, fouling, poor taste and odor. It is important to remove humic substances prior to chlorination, as any remaining NOM will react with the added chlorine to create undesirable disinfection by-products (DBPs) such as trihalomethanes (THMs). ABB offers two analytical methods for detecting organic matter in water: Aztec 600 Color Analyzer