A Study on Brine Resource Utilization in Desalination Plants

In this study, we utilized electrolytic catalysis technology and the concentrated brine from the Matsu Nankan Desalination Third Stage Plant to develop a brine resource utilization process, producing a multi-oxidant with disinfection efficacy, containing chlorine dioxide (ClO2), chlorine (Cl2), ozone (O3) and hypochlorous acid (HOCl). This experimental result is expected to achieve waste resource utilization by using the waste concentrated brine as an electrolyte material to produce disinfectants by an electrolysis procedure. The disinfectant generated can also be used in many sterilizing processes in the plant. In the study, the optimal operational conditions were controlled at 40 ℃ for temperature and 12 V for cell voltage. 6 % NaClO2 was added into the same brine. Under these optimum conditions, the major product became ClO2 with a maximum concentration of 1074 mg L-1. Comparing the disinfection efficacies between 1 ppm of commercial 10 % hypochlorous acid and the multi-oxidant produced in this study, the efficacies of hypochlorous acid and the multi-oxidant reached 28 % and 93 %. The latter was three times greater than the former. In conclusion, the multi-oxidant produced by recycling the brine from desalination plants was expected to have applicability and economic value.