# Innovative Approaches for Minimizing Disinfection
## 4 DBP Minimization Approaches
### Advanced Water Treatment Technologies
#### 4.5.4 Membrane Nanofiltration  
While MF and UF processes are characterized by ease of handling and relatively low operating costs due to the low pressures required, their performance in DBP removal is limited by the large pore sizes of the membranes and the high molecular weight cut-off (MWCO) range, typically between 1 and 200 kDa. These characteristics make it challenging for MF and UF to effectively remove relatively small DBP molecules. The small molecular size of DBPs compared to the large MWCO of MF and UF membranes makes it easy for the DBP molecules to pass through the membrane pores into the permeate stream. The removal efficiency of DBPs by MF is typically around 20%, mainly due to biodegradation or adsorption. MF and UF are commonly used as pretreatment steps to eliminate particles and colloids from the feed water, aiming to prevent fouling of the subsequent NF or RO membranes rather than being the primary method for DBP removal. NF demonstrates intermediate performance between UF and RO, as NF offers better retention properties than UF by effectively rejecting multivalent ions and low-molecular-weight organic substances. At the same time, NF does not require as high an operating pressure as RO. So, in essence, NF presents a middle ground between the capabilities of UF and RO with better rejection performance than UF for specific contaminants and lower operating pressure requirements than the more energy-intensive RO process. This makes NF an attractive option, as it can provide an enhanced removal of DBPs and other organic micropollutants while operating at a reduced energy cost compared to the RO process. The intermediate nature of NF's performance characteristics positions it as a valuable alternative membrane technology for water treatment applications where UF is insufficient, but RO may not be necessary or feasible [12].  
Membrane technology has attracted considerable interest in eliminating organic micropollutants (OMP) due to its simple operation and various technological advantages, including low energy consumption, decreased carbon footprint, and minimal space requirements compared to conventional separation methods. Additionally, membrane systems provide continuous operation and can easily be integrated with current treatment technologies. The most successful commercial membrane products for water treatment include RO and NF membranes made from thin-film composite (TFC) materials. These membranes are commonly manufactured through a cost-effective, scalable, and highly reproducible interfacial polymerization (IP) process conducted from roll to roll. Interfacially polymerized membranes are known for their high-water permeability, outstanding salt rejection (>99%), robust mechanical stability, and broad pH tolerance. The utilization of TFC membranes is a significant contributing factor to pressure-driven membrane processes representing over 60% of the global desalination capacity. These TFC membranes play a crucial role in the dominance of pressure-driven membrane processes, accounting for more than 60% of the worldwide desalination capacity. Previous studies have highlighted the potential of TFC-based RO and NF membranes in removing OMPs from various water sources. However, a notable drawback of current membrane types is their limited ability to reject neutral and slight molecular weight OMPs, especially those that are highly hydrophobic or polar. The rejection of OMPs is influenced by various factors, including: (i) the intrinsic properties of the membrane, such as surface charge, pore size, molecular weight cut-off (MWCO), contact angle, and surface morphology; (ii) the characteristics of the solute, including molecular weight (Mw), acid dissociation constant (pKa), geometry, octanol-water partition coefficient (log Kow), and water solubility; (iii) the chemistry of the feed solution, such as hardness, pH, and ionic strength; and (iv) the operating conditions, including temperature and transmembrane pressure [33].