Study On Techniques And Mechanism Of Disinfection Of Reclaimed Water By Microwave Discharged Electrodeless UV Lamp

The water shortage has become a worldwide problem. Reclaimed water canbring considerable environmental and economic benefits. With advances intechnology and people’s environmental health awareness, the security issues causedby traditional chlorine disinfection gradually attract people’s attention. People becomefocus their attention on the new security disinfection. Microwave dischargeelectrodeless lamp is a new UV light source, the advantage is to stimulate fastluminous efficiency, long life, and diverse in shape, no electrons. Therefor, it hasbecome a hot topic.In the study, homemade microwave electrodeless UV disinfection unit was usedin analog secondary settling tank water and the actual secondary settling tankdisinfection. E. coli and B. subtilis were selected to discuss the disinfectioninfluencing factors and microwave electrodeless ultraviolet synergy mechanism.The optimal disinfection conditions were obtained through the research. When2discharge lamps and500mL water were placed in the disinfection device, microwavepower was600W, after20s irradiation, the fatality of bacteria in the simulated watersamples was3.47. The turbidity has little affect on the disinfection effect whenturbidity <10NTU. The study of actual secondary settling tank effluent have shownthat after20s irradiation the Escherichia coli can not be detected, after35sirradiation the fatality of bacteria was3.5. After40s irradiation the residual viablecount of24h photoreactivation＜100CFU mL^-1. The research of the dark repair ofthe bacteria in the actual secondary settling tank effluent have shown that COD, TOCdecreased slightly after40s irradiation. Compared with the microwave, UV, UV/water bath disinfection effect, microwave electrodeless UV disinfection was moreefficient, less photoreactivation.The study of representative bacteria have shown that compared with E. coli, B.subtilis is more difficult to kill, but extend the irradiation time can do it. Theconcentration of bacteria affect the total disinfection time, disinfection rate in the early is not significantly affected. The UV discharge lamp play a leading role indisinfection process, there is a synergistic effect. After irradiation of microwaveelectrodeless UV lamps the bacterial surface folds, atrophy, membrane permeabilitychanges, K+and protein leakage, compared with microwave and ultraviolet, themicrowave discharge electrodeless have stronger effect on cell damaging.