Preliminary Study onWhole-Phase Control of Photoreactivationafter Ultraviolet Disinfection

摘要

To control photoreactivation of Escherichia coli after UV disinfection, three strategies of reducing the initial photoreactivating microorganism concentration, delaying ultraviolet (UV) disinfected bacteria exposing to photoreactivating light, and secondary disinfection have been studied here. The experimental results showed that, UV dose, as high as 80 mJ/cm~2, could control percentage photoreactivation of E. coli at 6.1x10~(-4)%. Peroxide acid of 3 mg/L helped UV to reduce percentage photoreactivation below 10~(-4)%. Potential photoreactivation potential could recover immediately after water samples were kept in darkness for less than 6 h. Chlorine of 3 mg/L was the lowest concentration to inhibit photoreactivation for 24 h in the study situation.