On the discussion on the comparison of methods for calculating aeration tanks with the removal of nitrogen and phosphorus (for the discussion)

Summary

The arguments of the authors of the book «Calculation and process engineering of processes and facilities for the removal of nitrogen and phosphorus from municipal wastewater» are given in response to the critical article by O. V. Khar’kina in the «VST» journal on the method proposed for calculating aeration tanks. Based on the literature review, it is shown that the calculation of aeration tanks in terms of the sludge age is not empirical, however based on the kinetic laws; and, herewith, in the field of application recommended by the authors, the use of a smaller number of empirical coefficients is required eliminating their choice. Explanations are given why accounting for the concentration of dissolved oxygen and calculation for the nitrite nitrogen concentrations less than 0.05 mg/l should not be included in the calculation procedure. Explanations are given for the dependence of kinetic coefficients on the concentrations in the effluent because of the change in the species composition of nitrifiers according to the theory of competitive exclusion of species. Information is provided on the successful comparison of the methods proposed by the authors with the simulation in the GPS-X program and on the operation of a new block of the Liubertsy Wastewater Treatment Facilities (Moscow), calculated according to the method. The operation of the block testifies to the complete sufficiency of the volume of the aerobic zone of the aeration tanks.

Key words

wastewater , biological treatment , nitrification , simulation , sludge age , kinetic coefficients