Biological Wastewater Reactor with Low-Density Packed Bed
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Solution Overview
Problem
Existing biological wastewater treatment methods face limitations in achieving high biomass concentration and purification efficiency due to issues with energy consumption, particle loss during backwashing, and inadequate oxygenation, particularly in systems using fluidized beds and fixed beds with particles near water density.
Innovation Solution
A biological reactor design featuring a packed bed with particles of low density and hollow carriers with high specific surface area, allowing co-current flow of water and oxygenated gas, and periodic counter-current backwashing to maintain a compact and efficient biofilm environment, reducing energy consumption and particle loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If materials heavier than water (such as sand) are fluidized, then the material can be kept inside the reactor, but a considerable input of energy is needed for the pumping of the liquid
Solution Approach 1:
The patent applies the anti-weight principle by using gas bubbles as a counteracting force to offset the weight of the particles. The gas injection creates buoyancy forces that counterbalance gravity, allowing particles to be suspended and retained in the reactor without requiring high pumping energy. This resolves the contradiction by replacing mechanical pumping energy with gas-driven buoyancy forces.
2Use of energy by moving object
If light materials with lower density than water are used in a fluidized bed with air insufflation, then energy consumption is reduced, but air bubbles are trapped within the material or carried along by the liquid flow when downflow speed increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the gas flow rate and liquid downflow velocity parameters. By optimizing these parameters, the system maintains a state where gas bubbles effectively aerate the reactor without being trapped or carried away. The gas flow rate is adjusted to provide sufficient aeration while the liquid velocity is controlled to prevent bubble escape, resolving the contradiction through parameter optimization.
3Loss of substance
If a packed bed of particles is used to maintain a compact structure, then particle loss during backwashing is minimized, but oxygen transfer to the biomass may be inadequate
Solution Approach 1:
The patent applies periodic action by implementing cyclic backwashing operations. During normal operation, the packed bed maintains a compact structure for low particle loss. Periodically, the system performs backwashing to restore bed structure and prevent excessive particle accumulation, then returns to the compact packed state. This periodic cycling resolves the contradiction by balancing particle retention with periodic restoration of optimal bed conditions for oxygen transfer.
4Productivity
If the biomass concentration is increased in free biomass techniques, then purification potential is improved, but the settling capacity becomes insufficient
Solution Approach 1:
The patent applies the intermediary principle by introducing a granular filter bed as a mediator between the biomass and the water flow. The filter bed provides a structured environment that supports high biomass concentration while maintaining effective separation. The granular material acts as an intermediary structure that enables both high productivity through increased biomass and reliable settling through the filter matrix, resolving the contradiction.
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
This design enhances wastewater purification efficiency by maintaining a compact packed bed, minimizing particle loss, and optimizing oxygen transfer, leading to improved removal of suspended solids and chemical oxygen demand while reducing energy consumption and backwash frequency.
Implementation Method 1
a gas injection system located in a lower area close to the bottom of the said space for expansion and removal of sludge
Implementation Method 2
the water to be treated and oxygenated gas are sent in ascending co-currents in the same reactor
Implementation Method 3
a biological filter comprising a packed bed of particles retained in a lower part of said reactor and a volume of movable particles located within the said space for expansion and removal of sludge
Implementation Method 4
the biological treatment, for example of water, consists in degrading the organic impurities by the action of a purifying biomass
Implementation Method 5
periodic counter-current backwashing to maintain a compact and efficient biofilm environment
Data Source
AI summary
A biological reactor for treating wastewater. The reactor includes a gas injection system and a system for directing wastewater into the reactor. Further, the reactor includes a biological filter comprised of a packed bed of biofilm carriers and a volume of moveable biofilm carriers. During the method of treating the wastewater, the wastewater moves upwardly through the reactor and through the biological filter while gas is emitted from the gas injection system.