Gas-hydrodynamic characteristics of aerotanks

Abstract

The purpose of the research was to determine the hydrodynamic indicators of aerotanks determining the depth and effectiveness of wastewater treatment. The study of technological parameters of the aeration tank was carried out on a physical model representing a transverse vertical section of the aerotank. The hydrodynamic similarity in the model and industrial aerotank determined by the identical values of the Reynolds, Froude, and Euler criteria. The study of similar indicators on an industrial aeration tank is very difficult and costly. The model and experimental setup make it possible to vary in a wide range the intensity of air aeration, the design and location of the aerator, control the speed of hydrodynamic flows and the concentration of freely floating sludge in the facility with aeration. To study the gas-hydrodynamic indicators in the aerotank model, original methods based on the laws of physical chemistry have been developed and used. The contact surface of the phases “liquid - gas” from the intensity of air aeration was determined using a chemical method for aerated biological wastewater treatment facilities. The dependences of the specific contact surface of the phases “liquid - gas”, referred to the unit of the working area of the aerator, on the intensity of aeration and the depth of immersion of the aerator are obtained. The oxidizing ability of a fine bubble aerator was determined for various aeration intensities. The dependences of the oxidizing ability on the contact surface of the phases ‘liquid - gas” in aerotanks were obtained for the first time. It is shown that the oxidation ability of the aerotank is determined by the phase contact surface and, to a large extent, by the hydrodynamic situation in the aerotank, which forms the fields of freely floating activated sludge.