The process of biological wastewater treatment in a mixing aeration tank for the purpose of its intensification is studied. Two variants of intensification are considered-hydraulic partitioning of aeration volume of the mixing aeration tank and use of a vortex aerator. It is proposed a calculation method of partitioning of aeration volume of the mixing aeration tank, and it is shown that partitioning can increase its performance by 1.8 times and reduce power consumption of the aeration system. The new design of the vortex aerator is described, and it is shown that its use will significantly increase the efficiency of the tank aeration system and intensify the process of biological treatment due to the increased turbulence of the activated sludge flow. In this case, the quantity of oxygen utilization rate is  u = 0.14-0.18, the relative concentration of organic contaminants is reduced to 0.20 at oxygen deficit 10% during the first aeration hour.

The results of theoretical studies of the hydrodynamic laws of fluid flow and changes in the characteristics of the wall layer of the flow in tubular mixing devices, used in technological processes of reagent-based wastewater treatment, are presented. A mathematical relation, which allows determining the critical value of the Reynolds number Re, at which the regime of fluid movement in a tubular mixing device passes into the region of the quadratic resistance law of rough channels with the maximum degree of turbulence of flows, is obtained. It is shown that the main technical characteristics of tubular mixing devices are: the magnitude of the pulsation component of the local velocity ∆υ l (m/s) and the value of the turbulent diffusion coefficient D T (m 2 /s) in the wall region of the turbulent fluid flow. Mathematical relations, which allow calculating the magnitude of the pulsation component of the local velocity and the turbulent diffusion coefficient in the wall region of the fluid flow in the pressure channels of circular cross section, are obtained. Using the proposed calculation technique will allow to optimize the operation regime of tubular mixing devices.