Pilot study of disinfection of a tertiary municipal effluent for reuse by ultraviolet(UV)light

摘要

In this study,a pilot plant was built to examine the potential disinfection efficiency for the reclaimed water from a tertiary municipal wastewater treatment plant with UV light.Experiment results showed that UV light disinfection is effective in removing pathogen and the efficiencies for total coliforms can reach as high as 99.9％(more than 3log).UV dose has a good correlativitv with irradiation time.At the irradiation time of 9.6 sec,which corresponds to an effective UV dose of 97 mJs/cm2.The number of total coilforms could be reduced from 6×104 tO 62 Cfu/L.Further increasing the irradiation time to 33.6 sec.which corresponds to an effective UV dose of 340 mJ/cm2.The rest active total coilforms number was reduced to 18 cfu/L.The inactive efficiency strongly corresponded with turbidity and colourness.Which suggested that pretreatment before disinfection would be a prerequisite for high quality effiuent.At the same time,COD,NH3-N.Turbidity and colourness in effluent were also reduced due to bacteria inactivation.