Discrete-Pulsed Energy Input in Wastewater Treatment Technologies

Abstract

Wastewater treatment is an important environmental problem of the national economy of any country. Therefore, increasing the efficiency of wastewater treatment through the use of innovative technologies and equipment is becoming relevant. Basically, for the biological treatment of wastewater from organic and biogenic pollution, aerotanks with different aeration systems are used. The aeration and mass transfer of the mixture of waste water and activated sludge accounts for up to 80 % of operating costs. The article deals with the problems of using thermal physics in wastewater treatment by intensifying the mass transfer process and accelerating the biological oxidation reaction. The intensification occurs due to the impact on the treated medium (waste water) of the input energy by the discrete-pulse method. The method is implemented using new heat and mass transfer equipment, namely a rotary-type aerator-oxidizer (AORT). A diagram of a rotary-type aerator-oxidizer and a technological scheme for biological wastewater treatment using this apparatus are presented. A procedure has been developed for determining the volumetric coefficient of oxygen mass transfer from the gas phase to the liquid phase during biological wastewater treatment. A number of studies have been carried out on the dependence of the concentration of oxygen dissolved in water on the number of treatment cycles at: different angular speed of rotation of the rotor unit; different frequencies of flow pulsations; different flow shear rates. It is shown that the maximum concentration of dissolved oxygen is reached in 1–2 passes through the apparatus of the processed mixture. The thermophysical and energy characteristics of the operation of a rotary-type aeration-oxidation plant are determined depending on the frequency of flow pulsations. A comparative assessment of the heat-mass exchange and energy indicators of modern aeration devices used for wastewater treatment with the AORT installation has been carried out and it has been shown that when using the AORT installation, energy costs for aeration are reduced by 20 %.