An assessment of the oxidizing ability of activated sludge used in the process of biological wastewater treatment was carried out when it was treated with a direct electric current on an electrohydrodynamic device. The efficiency of biological wastewater treatment is analyzed when the DC voltage changes, the sign of polarization of the electrode, as well as the values of the Camp criterion. It is shown that the electrotreatment of activated sludge leads to an increase in the efficiency of biological wastewater treatment, determined by the indicator of chemical oxygen consumption. A relationship has been established between the intensity of sludge treatment and the magnitude of the zeta potential of activated sludge at the outlet of the aeration tank.

Keywords: wastewater, biological treatment, activated sludge, electrohydrodynamic device, zeta potential, chemical oxygen consumption

Experimental studies have been carried out to determine the sludge index of activated sludge used in the process of biological wastewater treatment on aerotanks at various doses of sludge. The possibility of changing the sedimentation properties of activated sludge when using its electrical treatment is analyzed. It is shown that the electrotreatment of returnable activated sludge together with aeration leads to a decrease in the value of the sludge index, as well as an improvement in the quality of the treated water after settling. pretreatment of activated sludge in an electrolyzer with aeration allows biological wastewater treatment in an aerotank with increased doses, as well as to increase the flocculating properties of sludge in relation to suspended solids.

Keywords: household waste water, biological treatment, activated sludge, aerotank, sedimentation, sludge index, electrical treatment, aeration

The parameters of the mixers widely used in the practice of water treatment are given. A fundamentally new design of the mixing unit is proposed, which provides a process of rapid and complete mixing of reagents in a thin layer of a rotating flow of a pre-created water-air mixture using the method of concentrated coagulation. At the same time dispersion of air bubbles is carried out. A detailed description of the design, operating principle and basic design parameters of the mixer used in the mixing unit.

Keywords: natural water, coagulant, mixer, concentrated coagulation, aeration, velocity gradient, rotational motion