Waste Water Sterilization by Cobalt Co-60 for the Agricultural Irrigation: A Case Study

2 Abstract: The aim of this paper is to study of establishment a fourth stage of the secondary and tertiary treatments plant for sterilization wastewater. This will reduce the biological loading including vital viruses and parasite eggs by usage of gamma radiation of the Cobalt-60 ( Co- ) (1.16 Me.V and 1.33 Me.V. The cobalt can't 60 make artificial radiation; therefore it is safe and cheap to solve the chemical treatment problems and to avoid chlorine components in the environment. In this comparative study it was completed between the electron rays (e-beam), UV lamps, ozone unites, chlorine, mechanical regimes treatment and gamma rays for sterilization of both of wastewater and sludge samples from Al Hofuf wastewater treatment plant with determining advantages and disadvantages for each of these sterilization methods and the location where it should to be applied. It was found that a 16.2 kGy dose is generally suitable for the wastewater sterilization and it could be raised to above 25 kGy in case of only secondary treatment stage is applied and 27 kGy for sludge (SAL= 10 ). This will reduce 6 the chlorine poisons and the waste of livestock chicken and fishes and the industrial dismissal in the environment. Also it was clarified the biological reason behind of not applying these sterilization methods outside the experimental plants by studying the plant stages of the secondary and tertiary treatment in Al Hofuf, Saudi Arabia, which it was to let the aerobic bacteria to feed on organic material in wastewater and then the subsequent processing stages in the sedimentation downstream and using the irradiation first at the entrance of the station prevent to take advantage of that. This study demonstrated the potential of ionizing radiation to disinfect sewage and sludge and to increase the water quality in the wastewater by lowering the total heterogeneous bacteria.