Study of Sodium Ferrate Disinfecting Ability

More and more attention has been recently paid to the disinfection of industrial wastewater. Food, petrochemical, pharmaceutical, and other industries cannot directly dump wastewater into the environment, therefore, the wastewater is fed to the deep biological treatment lines. A high level of biological threat and the expanding list of potential pathogens cause the need to search for new highly efficient disinfecting agents. The use of ferrates can be a new step in the improvement of the wastewater disinfection process due to the combination of processes of inactivation of pathogenic microflora and the reactant coagulation on ferric hydroxides generated during decontamination (oxidation). Within the framework of the study, the potential use of sodium ferrate as a disinfecting agent obtained by electrochemical dissolution of iron electrodes in alkali solutions has been confirmed. It has been established that sodium ferrate can effectively inactivate conditionally pathogenic cultures A. niger, B. subtillis which are part of activated sludge symbiosis. The efficient dosing of ferrate for complete inhibition of B. subtillis is 0.5 % mass, whereas for A. Niger it is 15 % mass. It has been proved that microflora inhibition occurs directly under the action of sodium ferrate and not due to the alkali reaction of the medium. Industrial tests of the disinfecting ability of ferrates in relation to wasted activated sludge of industrial wastewater deep biological treatment systems have confirmed the results obtained for individual objects (A. niger, B. subtillis). Based on the results, a conclusion about the potential use of ferrates in the deep biological treatment processes for highly bacteriologically contaminated industrial wastewater has been made. The main advantages of the suggested agent include the low toxicity of metabolites, minimum secondary contamination of treated water, and possible reactant advanced treatment (dephosphorization).