Kinetic control of sodium hypochlorite electrolysis process and disinfection effect in sewage treatment

In order to increase the chlorine production of sodium hypochlorite electrolysis process and meet the disinfection requirements of effluent from the advanced treatment unit in township sewage treatment station, from the perspective of reaction kinetics, the influence of electrolytic parameters such as saline concentration, current density and electrolytic temperature on the production process of sodium hypochlorite was investigated, and the influence of effluent quality of the advanced treatment unit on the disinfection effect of sodium hypochlorite was analyzed, to clarify the influence mechanism of electrolytic parameters and effluent quality. The results showed that the temperature effect, chlorine evolution potential, disproportionation reaction and activation energy could be effectively controlled by adjusting the saline concentration, current density, electrolytic temperature and time to 40 g/L, 20 A/dm², 32 ℃ and 2.5 h, respectively, and then the yield of sodium hypochlorite could be increased to 9.28 g/L. When the dosage of sodium hypochlorite was at least 5 mg/L and the contact reaction time was 5 min, the sterilization performance of sodium hypochlorite against fecal coliform groups in denitrification filter effluent was more competitive than its oxidation performance of COD and ammonium, and could reduce the number of fecal coliform groups in water samples to 10^2.97 L^-1, and finally meet the bacteria index requirements of A-level standard of Discharge Standard of Pollutants for Municipal Waste-water Treatment Plant (GB 18918-2002).