Gravity Filter with Coarse Granular Medium for High-Speed Water Treatment
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Solution Overview
Problem
Existing water treatment installations using dissolved air flotation followed by gravity filtration have limitations in filtration speed and generate significant pressure drops, leading to increased costs and reduced efficiency, especially when dealing with challenging water quality or algae growth.
Innovation Solution
A water treatment installation with a dissolved air flotation reactor partially superimposed on a gravity filter, using a single-layer granular filter medium with particle sizes between 1.5 mm and 5 mm, distributed over a height of less than 1 m, allowing for higher filtration rates and reducing structural height and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fine-grained filtration materials (0.5-0.8 mm) are used in gravity filters, then effective filtration and sufficient water quality are obtained, but filtration speed is limited to 10-30 m/h and pressure drop increases significantly
Solution Approach 1:
The invention changes the particle size parameter of the filter medium from conventional fine grains (0.5-0.8 mm) to coarse grains (1.5-5 mm). This parameter change allows the filter to operate at higher speeds (greater than 30 m/h) while still providing effective filtration, thereby resolving the contradiction between water quality and filtration speed
Solution Approach 2:
The invention applies local quality by using coarser filter material specifically in the gravity filter section that receives pre-treated water from the flotation reactor. The flotation pre-treatment removes sufficient suspended matter to allow the gravity filter to use coarser media without compromising overall water quality, enabling the local optimization of filtration speed
2Productivity
If the height of filtration material is increased to achieve higher filtration speeds, then productivity improves, but pressure drop and total structure height increase, generating higher costs
Solution Approach 1:
The invention changes the particle size parameter of the filter medium to coarse grains (1.5-5 mm), which allows achieving high filtration speeds without increasing filter height. The coarser media provides sufficient filtration capacity at lower heights, thereby avoiding increased pressure drop and structural costs while maintaining high productivity
3Reliability
If independent DAF installation followed by filtration device are used, then effective water treatment is achieved, but the facility occupies a large footprint
Solution Approach 1:
The invention merges the DAF reactor and gravity filter into a single integrated facility where the flotation reactor is positioned directly above the gravity filter. This vertical integration allows water to flow by gravity from the flotation zone into the filter, eliminating the need for separate buildings or large horizontal spacing, thereby reducing facility footprint while maintaining treatment effectiveness
Solution Approach 2:
The invention transitions from a horizontal arrangement of separate DAF and filtration facilities to a vertical stacked configuration. By utilizing the vertical dimension, the system achieves space-efficient integration where the flotation reactor sits above the gravity filter, allowing gravity-driven flow without requiring additional horizontal space
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 solution enables filtration rates greater than 30 m/h while maintaining water quality suitable for subsequent membrane filtration, reducing the need for fine-grained filtration materials and minimizing installation costs by using coarser filter media and a compact design.
Implementation Method 1
a dissolved air flotation reactor (4) comprising an inlet connected to said supply means, and/or optionally an inlet connected to the outlet of said coagulation and/or flocculation zone
Implementation Method 2
a gravity filter, said flotation reactor being at least partially superimposed on said gravity filter and communicating with it so that the water coming from said flotation reactor can flow by gravity into said gravity filter
Data Source
Figure 1
AI summary
The invention is within the technical field of water treatment. A subject of the invention is a water treatment facility, comprising: means for conveying the water to be treated 1, optionally a coagulation zone 2 and/or a flocculation zone 3, into which said means for conveying the water to be treated open, a flotation reactor 4 comprising an inlet and a gravity filter 5, the water originating from said flotation reactor can flow by gravity into said gravity filter, the latter has a single-layer filtering media bed distributed over a height of less than 1 m. A facility according to the invention may also comprise a means for washing the gravity filter and/or a membrane filter for the filtration of the water originating from the gravity filter. Another subject of the invention is a water treatment process implemented using a facility according to the invention.