Two-Stage Sedimentation for Aerobic Granular Sludge
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Solution Overview
Problem
Current aerobic granular sludge (AGS) processes face challenges in achieving high final suspended solid removal rates and efficient phosphorus removal, particularly due to the complexity of phosphate-accumulating microorganisms' growth conditions and the need for chemical coagulants, which increase engineering costs and sludge treatment difficulties.
Innovation Solution
A continuous-flow AGS process with a two-stage sedimentation system, comprising a biochemical reaction tank, a granular sludge sedimentation tank, and an inclined plate sedimentation tank, where an inclined device promotes rapid separation of heavy and light sludge, using a coagulant in the inclined plate tank to enhance floc formation and reduce separation time, thereby simplifying the process and reducing floor space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical coagulants are added for phosphorus removal, then phosphorus removal efficiency is improved, but engineering investment and sludge treatment costs increase
Solution Approach 1:
The patent extracts and removes the chemical coagulant addition step from the phosphorus removal process. Instead of adding chemicals, the system uses enhanced biological phosphorus removal through optimized anaerobic-anoxic-oxic conditions and two-stage sedimentation, eliminating the need for chemical coagulants and their associated infrastructure
Solution Approach 2:
The patent enables the system to self-remove phosphorus through indigenous phosphate-accumulating microorganisms that naturally accumulate phosphorus under controlled environmental conditions. The two-stage sedimentation process allows these microorganisms to self-settle and be removed as waste activated sludge without external chemical intervention
2Manufacturing precision
If chemical coagulants are used for phosphorus removal, then phosphorus removal efficiency is improved, but sludge generation and treatment difficulty increase
Solution Approach 1:
The patent removes the chemical coagulant addition step that generates chemical sludge. The system achieves phosphorus removal through biological processes alone, eliminating the source of chemical sludge generation and simplifying sludge management
Solution Approach 2:
The patent uses waste activated sludge as an intermediary carrier for phosphorus removal. Phosphate-accumulating microorganisms incorporate phosphorus into their biomass, and this biomass is then removed via the two-stage sedimentation process, providing a natural pathway for phosphorus elimination without chemical sludge
3Device complexity
If a single-stage sedimentation tank is used, then device simplicity is maintained, but suspended solid removal efficiency is insufficient
Solution Approach 1:
The patent divides the sedimentation process into two distinct stages: primary sedimentation for heavy granular sludge and secondary sedimentation for light flocculent sludge. This segmentation allows each stage to be optimized for its specific function, achieving high overall suspended solid removal efficiency
Solution Approach 2:
The patent applies different sedimentation conditions to different portions of the sludge mixture. Heavy granular sludge receives high-speed centrifugal separation, while light flocculent sludge receives inclined plate acceleration, with each portion treated according to its specific characteristics for optimal removal
4Device complexity
If heavy sludge and light sludge are not separated, then process simplicity is maintained, but AGS production promotion is limited
Solution Approach 1:
The patent segments the sludge mixture into heavy granular sludge and light flocculent sludge through two-stage sedimentation. This separation allows the heavy granular sludge to be concentrated and returned to the reactor for AGS production, while light sludge is removed as waste
Solution Approach 2:
The patent uses dynamic flow control to separate sludge based on density differences. The system dynamically adjusts the separation process to concentrate granular sludge and remove flocculent sludge, creating optimal conditions for continuous AGS production
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 system achieves high suspended solid removal rates, simplifies the process flow, conserves energy, and reduces sludge generation points, making it more economical and manageable, while ensuring effective phosphorus removal without negative impacts from residual chemical agents.
Implementation Method 1
heavy sludge in the sludge-water mixture is quickly settled in the granular sludge sedimentation tank
Implementation Method 2
an inclined device promotes rapid separation of heavy and light sludge
Implementation Method 3
using a coagulant in the inclined plate tank to enhance floc formation
Implementation Method 4
enhance floc formation
Data Source
AI summary
A method and a system for a continuous-flow aerobic granular sludge (AGS) process with improved two-stage sedimentation are provided. The method includes the following steps: arranging a biochemical reaction tank, a granular sludge sedimentation tank, and an inclined plate sedimentation tank that are connected sequentially, and arranging an inclined device in the inclined plate sedimentation tank; allowing sewage to continuously flow into the biochemical reaction tank, and allowing a sludge-water mixture obtained after a biochemical reaction to enter the granular sludge sedimentation tank, such that heavy sludge in the sludge-water mixture is quickly settled in the granular sludge sedimentation tank and returned to the biochemical reaction tank; and allowing light flocculent sludge in the sludge-water mixture to flow into the inclined plate sedimentation tank.