Study of the aeration intensity effect in a bioreactor on the pressure head

Summary

The design of a bioreactor with vertically arranged anoxic and aerobic zones is described. The bioreactor is designed for wastewater biological treatment at the facilities ranging from ultra-small to low-capacity ones. It is shown that the given bioreactor type is characterized by the ease of operation owing to the lack of circulation pumps and mixers. The pressure head dependence on the aeration intensity and gas filling coefficient in the aerobic zone of the bioreactor is presented. It has been established that the gas filling coefficient in the aerobic zone of a bioreactor operating under static conditions eliminating liquid overflow into the anoxic zone can be calculated as the ratio of the aeration intensity to the average air bubble rise rate. It has been determined that air bubbles generated in industrial pneumatic fine-bubble aerators rise in a turbulent mode at a rate proportional to the bubble diameter raised to the power of minus 0.4. The results obtained in this investigation will be used in the second part of the experimental and theoretical studies that will provide for determining the dependence of the circulation flow rate on the aeration parameters, and developing a mathematical model of the fluid flow in a bioreactor with the vertical arrangement of aerobic and anoxic zones.

Key words

wastewater , biological treatment , aeration , bioreactor , anoxic zone , aerobic zone , gas filling coefficient