High energy electron disinfection of sewage wastewater in flow systems

The disinfection of eflluent municipal wastewaters by high-energy electrons in flow systems was studied using an experimental apparatus which has the maximum treatment capacity of 10.8 m 3 /h. An electron accelerator with an accelerating voltage of 2 MV was used. The electron beam current was controlled to deliver the desired doses ranging from 0.05 to 1 kGy. Treatment times were in the range from 0.0022 to 0.051 s. Pleriminary experiments with batch system using Petri dish of 100 ml showed that the effectiveness of electron irradiation on inactivation of coliforms was not influenced significantly by factors such as pH, SS, COD, DO and irradiation temperature. The dose required to produce 99.9% kill in the total population presented in wastewater were markedly affected by the thickness of water exposure to electron irradiation; that is, 0.39, 0.4 and 0.44 kGy for the depth of 5, 6 and 7 mm, respectively. The data obtained after a suitable correction for the doses due to the depth dose distribution showed no deviation from an experimental survival curves. Experiments with flow system indicated no mesurable effect of the flow rate of wastewaters on the efficiency of disinfection in the range from 0.5 to 3.5 m/s.