Sludge Treatment Technology and Ionizing Radiation

The application of radiation hygienization of sludges in sewage works can be affected by secondary effects of this process. The change of the colloidal system of liquid sludges by irradiation results in an improvement of their thickening capacity, but at the same time produces an increase in the demand for polymer flocculants for the conditioning of sludges prior to their dewatering. The irradiation dose of 3 kGy decreases the concentration of Salmonella senf. by at least 6 orders, and at the same time the reinfection of the sludges by prolonged storage is suppressed. Two years of field tests showed higher potato and barley yields with irradiated sludges compared with non-irradiated sludges. The economic evaluation demonstrated under Czechoslovak conditions the suitability of the use of electron accelerators as radiation sources and the introduction of ionizing radiation behind the mechanical sludge dewatering process.