# Innovative Approaches for Minimizing Disinfection
## 3 DBPs
### DBPs Precursors--Natural Organic Matter (NOM)
This sustained focus underscores the importance of optimizing the water treatment process to mitigate the formation of potentially harmful disinfection byproducts while maintaining the necessary level of microbial disinfection to protect public health [25]. While DBPs in drinking water pose a significant environmental health risk, the main objectives of drinking water disinfection are pathogen inactivation and the prevention of regrowth. This underscores the necessity of chlorine disinfection for the foreseeable future. Hence, striking a balance between pathogen inactivation and managing DBP formation is a complex yet crucial global concern [14]. The decrease in DBPs is typically accomplished by physically removing organic precursor materials through coagulation or enhanced coagulation along with flocculation, sedimentation, and filtration processes like granular activated carbon or membrane filtration. Utilities can also adopt alternative disinfection methods such as ozonation or ultraviolet disinfection to achieve disinfection objectiveswhile minimizing the requirement for chlorine. However, some of these alternative disinfectants may also generate DBPs (for example, the production of bromate from ozonation) or may be less efficient in deactivating specific pathogenic microorganisms [26]. Typically, the water supply system includes coagulation and flocculation, sedimentation, and sand filtration, followed by disinfection, before the water is distributed through the network. Sedimentation and sand filtration processes are efficient in eliminating suspended solids and turbidity. However, dissolved organic matter (DOM), which consists of molecules smaller than 0.45 \(\upmu\)m, such as dissolved organic carbon (DOC), humic acid, and fulvic acid, cannot be effectively removed by the sand filter tank. The most used disinfectants in the disinfection process are chlorine, chloramines, ozone, and chlorine dioxide. The classical water treatment steps include the following:  
* Coagulation and flocculation: This help to agglomerate small particles into larger, more easily settleable flocs. * Sedimentation: The flocculated particles settle from the water during this sedimentation stage (Figure 2). * Bed filtration: The water then undergoes filtration through sand (Figure 3), gravel, and other materials, effectively removing suspended solids and turbidity. * Disinfection: Finally, the water is disinfected, commonly by using chlorine, chloramines, ozone, or chlorine dioxide, before being distributed through the supply network. While sedimentation and sand filtration processes are efficient at removing suspended particles, they are less effective at eliminating DOM, such as humic and fulvic acids, which are smaller than 0.45 \(\upmu\)m in size. The sand filtration step cannot efficiently remove this dissolved organic material [27]. The treatment process commonly used, granular activated carbon (GAC) adsorption (Figure 4), only removes a small portion of NOM due to its heterogeneous nature. As a result, it may not adequately address halogenated DBPs in treated water. Efforts have been focused on understanding the mechanistic formation of regulated THMs and HAAs during the chlorination of NOM to recommend effective strategies for controlling DBPs. Humic substances present in NOM contain numerous unsaturated carbon bonds and aromatic structures, particularly active phenolic groups, which significantly generate HAAs, THMs, and other halogenated DBPs [28]. Figure 2: Sedimentation tank. It has been noted that hydrophilic and low-molecular-weight NOM tend to react preferentially with bromine and iodine, whereas hydrophobic and high-molecular-weight NOM typically result in an increased production of halogenated chlorination byproducts. NOM exhibits diverse chemical compositions, varying from simple aliphatic structures to complex-colored aromatic substances, encompassing a broad spectrum of organic compounds.