Movable Inlet Decanting Apparatus for Sequencing Batch Reactors
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Solution Overview
Problem
In wastewater treatment plants using sequencing batch reactors (SBRs), the sedimentation and decanting phases are prolonged due to the limitations of air-lift pumps, which either have low hydraulic delivery at small submersion or risk sludge entering the pump during operation, contaminating the treated water.
Innovation Solution
A decanting apparatus separates treated water from the reactor and pumps it into a separate air-lift pump tank, with the inlet submerged to the required depth, allowing for efficient decanting while preventing sludge contamination by maintaining the water level above the inlet and using a float component to manage water level fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the air-lift pump inlet is positioned deep under the water surface to ensure adequate hydraulic delivery, then the pump delivery is sufficient, but the sedimentation time is prolonged until the sludge interface falls deep enough below the inlet
Solution Approach 1:
The invention introduces a vertical movable inlet that adds the dimension of motion to the pump inlet position. Instead of fixing the inlet at a deep position (solving delivery) or shallow position (reducing sedimentation time), the inlet moves vertically to adapt to changing water levels, allowing shallow positioning during sedimentation and deep positioning during decanting.
Solution Approach 2:
The pump inlet is made dynamic rather than static. It moves vertically along with the water level during the decanting phase, maintaining optimal submersion depth. This dynamic adjustment allows the system to achieve adequate pump delivery without requiring excessively deep fixed inlet positioning that would prolong sedimentation time.
2Loss of time
If the air-lift pump inlet is positioned shallow to reduce sedimentation time, then the decanting process starts earlier, but sludge enters the pump during operation contaminating the treated water
Solution Approach 1:
The movable inlet adapts its position dynamically during operation. During the decanting phase, it maintains a shallow position relative to the water surface, allowing early start of decanting without waiting for prolonged sedimentation. The inlet moves with the water level, ensuring it remains above the sludge interface throughout the decanting process, thus preventing sludge contamination while minimizing sedimentation time.
Solution Approach 2:
The system uses the water level as feedback to control the inlet position. The inlet is connected to move vertically with the water level, automatically adjusting its depth based on the current operational phase. This feedback mechanism ensures the inlet remains at the optimal position to prevent sludge entry during decanting while allowing early initiation of the process.
3Ease of manufacture
If the air-lift pump is located directly in the pumped-off water to simplify design, then construction is more advantageous, but the pump inlet must be sufficiently deep under the water surface which causes time lag in sedimentation
Solution Approach 1:
The invention maintains the simple direct-location design of the air-lift pump in the pumped-off water but adds a movable inlet component. This movable inlet can be positioned shallowly during sedimentation (reducing time lag) and moves to appropriate depths during decanting (maintaining pump performance). This dynamic element preserves the construction advantages while eliminating the time lag problem.
Solution Approach 2:
The pump inlet is segmented from the main pump body, allowing independent movement of the inlet while the pump remains fixed in its simple location. This segmentation enables the inlet to adapt its position without complicating the overall pump installation, maintaining ease of manufacture while solving the sedimentation time issue.
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 solution significantly reduces idle time during sedimentation and decanting, ensures minimal sludge entry into the treated water, and enhances the hydraulic delivery of the air-lift pump, making it cost-effective and efficient.
Implementation Method 1
an air-lift pump for pumping off of the treated water... pressure air is in most cases available at the wastewater treatment plant
Implementation Method 2
in the sedimentation phase the activated sludge is separated from the treated water by settling near the bottom of the reactor
Data Source
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AI summary
The method of wastewater treatment and the method-applying apparatus in the sequencing batch reactors, where after separating the activated sludge from the treated water the treated water is drawn off via a decanting apparatus from the sub-surface layer of water in the reactor. The decanted water is conveyed by the decanting apparatus to a separate tank of the air-lift pump, which is separated in a watertight way from the inside of the reactor. The treated water is pumped off from the separate tank of the air-lift pump to the outlet by the air-lift pump, the inlet of which is located at the level corresponding to the delivery yield of the air-lift pump. The submerged inlet part of the decanting apparatus moves vertically alongside with the fluctuating water level in the reactor.