Mathematical modeling of the wastewater biological treatment process in a plug flow aeration tank

Summary

The results of theoretical studies of the kinetics of the processes of biochemical oxidation of organic wastewater pollution by activated sludge microorganisms are presented. It is shown that the value of the average effective value of the specific rate of organic wastewater pollution oxidation by the activated sludge in a plug flow aeration tank can be determined using the theorem on the average value of the continuous function f(L) integrated in a certain range of its variable from L_н to L_к. By integrating the Michaelis–Menten equation, a mathematical model was obtained based on the fundamental regularities of enzymatic kinetics that describes the process of biological oxidation of organic pollutants in a plug flow aeration tank. The use of the proposed equations will provide for determining the average effective values of the specific oxidation rates of various organic pollutants (BOD, oil products, surfactants, phenols, etc.), the estimated duration of aerobic processes; and thereby, optimizing the design and operation of biological wastewater treatment facilities in plug flow aeration tanks.

Key words

activated sludge , complete-mix activated sludge system , specific oxidation rate , biochemical oxidation , enzyme kinetics , plug flow aeration tank

Methods of determining flow velocity in open channels at turbulent regime

Summary

The turbulent flow structure and velocity distribution at turbulent liquid flow is considered. The methods of determining flow velocity in open channels based on keeping records of the speed of helix blade rotation, of the floating object speed, of the dynamic pressure, of the flow force impact; on the heat exchange principle; on measuring water amount entering the meter for the observation period; on the use of ultrasound; on the use of laser are presented. The error of measuring velocity by different methods is indicated. The profile of liquid velocity in a complete-mix activated sludge model system is specified.

Key words

turbulent flow , hydrodynamics , Reynolds number , actual velocity , Bernoulli equation , Pitot tube , ultrasonic flowmeter , laser method , complete-mix activated sludge system