Membrane Bioreactor Segmentation for Oxygen Transfer
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Solution Overview
Problem
Existing membrane bioreactors for sewage treatment face challenges such as oxygen limitation, biomass damage from shear forces, and inefficiencies in oxygen diffusion, leading to reduced biological activity and productivity, as well as issues with fouling and high energy consumption in sparging systems.
Innovation Solution
A membrane bioreactor with a support membrane having a gas face biolayer and a liquid face biolayer, allowing oxygen diffusion and nutrient transfer through a porous structure, supported by a gel and a fibrous material, which promotes aerobic microorganism growth and efficient oxygenation of sewage, reducing fouling and energy requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If mechanical agitation or pneumatic sparging is used to oxygenate and mix the biomass, then oxygen availability and mixing are improved, but shear forces damage fragile cultures and reduce biological activity
Solution Approach 1:
The system divides the bioreactor into distinct zones: an upper aerated zone with gas sparging for oxygenation, and a lower non-agitated zone for maintaining fragile biomass cultures. This segmentation allows different hydrodynamic conditions in different regions, enabling both efficient oxygen transfer and gentle biomass maintenance without mutual interference.
Solution Approach 2:
A membrane separator is introduced as an intermediary between the aerated zone and the non-agitated biomass zone. This membrane allows oxygen to diffuse from the aerated side to the biomass side while preventing direct mechanical contact between the sparged air and the fragile cultures, thus mediating the oxygen transfer without transmitting harmful shear forces.
2Productivity
If biomass concentration is increased to improve treatment capacity, then productivity increases, but viscosity increases reducing mixing efficiency and oxygen diffusion rate
Solution Approach 1:
The system transitions from relying solely on liquid-phase oxygen diffusion through dense biomass to incorporating gas-phase oxygen transfer at the membrane interface. By introducing a gas-side aeration zone with membrane contact, oxygen can transfer directly from gas to liquid at the membrane surface, bypassing the diffusion limitations imposed by high biomass viscosity in the bulk liquid.
3Use of energy by moving object
If conventional membrane systems are used for sewage treatment, then oxygen transfer is improved, but fouling occurs and energy consumption in sparging systems increases
Solution Approach 1:
The system segments the oxygen transfer function between two zones: bulk oxygenation occurs through gas sparging in the upper zone, while the membrane primarily serves to separate the two zones and provide a controlled interface. This reduces the membrane's exposure to fouling conditions compared to fully immersed membrane systems, as the membrane is positioned at the interface rather than being surrounded by bulk sewage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The membrane bioreactor effectively increases oxygen concentration in treated sewage, enhances biological activity, and reduces fouling and energy consumption, providing a more efficient and robust system for sewage treatment by supporting aerobic microorganism growth and efficient oxygenation.
Implementation Method 1
The support membrane is permeable to oxygen so as to allow oxygen to pass (e.g. diffuse) through the membrane from the gas face and/or the liquid face to the gas face biolayer and/or liquid face biolayer
Implementation Method 2
a support membrane having a liquid face and a gas face; a gas face biolayer at a location selected from on the gas face, in the support membrane near the gas face
Data Source
Figure 1
Figure 1a(i)~1a(vi)
Figure 2~2a
AI summary
The present invention discloses a membrane, optionally for use in sewage treatment. The membrane comprises a support membrane having a gas face biolayer on a gas face of the membrane and/or in the support membrane near the gas face, and a liquid face biolayer on a liquid face of the membrane and/or in the support membrane near the liquid face.