Significant decrease of THMs generated during chlorination of river water by previous photo-Fenton treatment at near neutral pH

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2012-02, Vol.229 (1), p.46-52
• Main Authors: Moncayo-Lasso, Alejandro, Rincon, Angela-Guiovana, Pulgarin, César, Benitez, Norberto
• Format: Article
• Language: English
• Subjects: Advanced oxidation processes; Disinfection by-products; Drinking water disinfection; Neutral photo-Fenton; NOM oxidation; Solar treatment; Trihalomethanes
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2011.12.001

► THMs generation decrease by reducing NOM concentration prior to the chlorination step. ► Photo-Fenton process at neutral pH is effective system for the NOM degradation. ► Solar photo-Fenton process can be used to obtain at low cost drinking water safe. An important issue in chlorine drinking water disinfection is the generation from natural organic matter (NOM) of disinfection by-products (DBPs), especially trihalomethanes (THMs). The THMs generation can be limited by reducing the levels of NOM prior to the chlorination step. Herein, photo-Fenton system under solar simulator degraded humic acid solutions (as NOM model compounds), as well as NOM contained in river water (Pance River, Cali-Colombia), and dramatically reduced THMs formation during the subsequent chlorination step. In both cases the initial pH of treated water was near to 7. In no pre-treated river water 100–160μg/L of THMs are formed during chlorination while values of 20–60μg/L were reached in water previously treated for 4h by neutral photo-Fenton under solar simulator. The decrease in the generated THMs/total organic carbon ratio suggests that mainly the NOM fraction sensitive to THMs formation was photo-degraded. Therefore, the neutral photo-Fenton reagent could be implemented as a technological option for NOM removal for limiting THMs formation during a subsequent chlorination step.