UV/chlorination process of algal-laden water: Algal inactivation and disinfection byproducts attenuation

The disinfection of algal-impacted surface waters results in high concentrations of disinfection byproducts (DBPs). Here, the formation of DBPs when water containing Pseudanabaena limnetica (P. limnetica) was disinfected combining chlorination and ultraviolet irradiation (UV) was investigated. Because of UV/chlorination to inhibit algal growth and reduce DBP formation effectively, the effects of UV doses, free chlorine doses, reaction time and pH on the formation of DBPs during UV/chlorination were studied. The results showed that higher UV dose, longer oxidation time, neutral and acidic pH were beneficial in controlling DBPs. Moreover, UV/chlorination could enhance the formation of brominated DBPs, and reduce the formation of chlorinated DBPs in algal solutions containing bromide. In addition, the DBP formation from intracellular and extracellular organic matter (IOM and EOM, respectively) derived from algae was compared. Finally, the economic efficiency of our system using the electrical energy per order (EE/O) was evaluated, which was calculated to be 18.68 kWh/m(3) during the reaction. This information indicated that UV/chlorination was a feasible treatment method for algal-rich water.