Abstract
Background: The issue of periodic aeration, which can be used as a tool in the process of biological wastewater treatment, has always received undeservedly little attention. Since the optimization of all technological processes in terms of productivity and energy consumption is a matter of time, so, in our opinion, a deeper study and research of physical and biological processes that affect the metabolism of microorganisms during periodic aeration is very important. Objectives of the work are i) determination of conditions of stable state of biocenosis of microorganisms during application of short-cycle periodic aeration regime, ii) drawing up a mathematical model of the aeration system that links the increase in biomass depending on the oxygen concentration, iii) determination of minimum limit concentrations of oxygen and microorganisms as conditions for system stability. Materials and Methods: The aeration system is modeled using a system of differential equations describing the dynamics of reproduction of microorganisms taking into account the supply of oxygen by the aeration system to ensure the metabolism of microorganisms. Experimental studies were carried out in an artificially made laboratory aeration tank (0.7 m´ 0.7 m ´1.2 m, with a volume of 500 liters). Results: The solution of the system of differential equations gave the conditions for the stability of the system, i.e. the limiting concentrations of microorganisms and oxygen per liter of liquid. Taking into account the stability conditions, an equation was derived to determine the threshold level of oxygen concentration at which it is necessary to end the aeration period. With the help of data obtained as a result of laboratory experiments, it became possible to numerically determine the coefficient of residual oxygen content γ, using which it is possible to determine the limiting oxygen concentration. Conclusions: From the systems of differential equations, which consist of the equation of reproduction of microorganisms according to the logistic model and the equation that describes the dynamics of oxygen concentration in the aeration tank liquid, the conditions under which the system has stability are found. From the conditions of stability the equation that sets the condition for shutting off the supply of oxygen to the aeration system in the algorithm of periodic aeration is followed. The optimal degree of purification and the total aeration time in the experiments testify that the interval of concentrations of O2 in the exhaust gases, at which the aeration period should be end, can be determined by this equation, taking the numerical value of the coefficient γ equal to 0.01–0.02.
Highlights
The issue of periodic aeration, which can be used as a tool in the process of biological wastewater treatment, has always received undeservedly little attention
Since the optimization of all technological processes in terms of productivity and energy consumption is a matter of time, so, in our opinion, a deeper study and research of physical and biological processes that affect the metabolism of microorganisms during periodic aeration is very important
Materials and Methods: The aeration system is modeled using a system of differential equations describing the dynamics of reproduction of microorganisms taking into account the supply of oxygen by the aeration system to ensure the metabolism of microorganisms
Summary
Метою роботи було: 1) визначення умов стабільного стану біоценозу мікроорганізмів під час застосування режиму короткоциклової періодичної аерації; 2) складання математичної моделі аераційної системи, яка пов’язує приріст біомаси з концентрацією кисню; 3) визначення мінімально граничних концентрацій кисню як умов стабільності системи. Аераційна система змодельована за допомогою системи диференціальних рівнянь, що описують динаміку розмноження мікроорганізмів з урахуванням подачі кисню аераційною системою для забезпечення метаболізму мікроорганізмів. З урахуванням умов стабільності було отримане рівняння, що дозволяє визначити пороговий рівень концентрації кисню, при якому необхідно закінчувати період аерації. З систем диференційних рівнянь, що складається з рівняння розмноження мікроорганізмів за логістичною моделлю та рівняння, яке описує динаміку концентрації кисню у рідині аеротенку, знайдено умови, за яких система є стабільною. З умов стабільності випливає рівняння, що задає умову відключення подачі кисню до системи аерування в алгоритмі періодичної аерації.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
