Cyclically Submerged Filter Discs for High-Flux Wastewater Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing filtering technologies, such as rotating disc filters and membrane bioreactors, face challenges in achieving high flux rates while maintaining effective pore sizes for wastewater treatment, with rotating disc filters sacrificing filtering degree due to larger pore sizes and membrane bioreactors experiencing clogging issues.
Innovation Solution
A filtering apparatus using liquid-permeable filtering elements with a dynamic membrane formed by cyclically submerged discs, combined with gas infusion and controlled deposition and removal of solid content, achieves high flux rates and fine filtration by maintaining a thin, permeable cake layer on the filtering elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotating disc filters use filter cloths with larger pore sizes, then flux rate is improved, but degree of filtering deteriorates
Solution Approach 1:
The filter cloth is cyclically moved between immersion in the liquid suspension and removal from it. During immersion, the filter cloth captures suspended solids; during removal, the filter cloth is shaken or tapped to discharge the accumulated solids. This dynamic operation allows the use of larger pore sizes while maintaining effective filtration through continuous cycle operation.
2Manufacturing precision
If membrane bioreactors use smaller pore sizes, then degree of filtering is improved, but flux rate deteriorates
Solution Approach 1:
The filter cloth is cyclically moved between immersion in the liquid suspension and removal from it. During immersion, the filter cloth captures suspended solids; during removal, the filter cloth is shaken or tapped to discharge the accumulated solids. This dynamic operation allows the use of larger pore sizes while maintaining effective filtration through continuous cycle operation.
3Manufacturing precision
If membrane bioreactors use smaller pore sizes, then degree of filtering is improved, but clogging tendency worsens
Solution Approach 1:
The filter cloth is cyclically moved between immersion in the liquid suspension and removal from it. During immersion, the filter cloth captures suspended solids; during removal, the filter cloth is shaken or tapped to discharge the accumulated solids. This dynamic operation allows the use of larger pore sizes while maintaining effective filtration through continuous cycle operation.
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 apparatus enables high-quality filtration with flux rates up to 5000 L/(m²h) and suspended solid content below 10 mg/L, while preventing clogging through controlled deposition and removal of the dynamic membrane layer.
Implementation Method 1
a plurality of liquid-permeable filtering elements, each filtering element having first and second opposite faces, which can be cycled into and out of the liquid
Implementation Method 2
The apparatus is arranged to introduce bubbles of gas into the liquid in such a way that some of the bubbles will attach to and lift deposited solid content back off the filtering elements and back into the liquid
Data Source
Figure 1
Figure 2~3
Figure 4~8
AI summary
A method of filtering a liquid (2), such as wastewater, is disclosed. The liquid has total suspended solids of between 1 and 50 g/L and the method uses a liquid-permeable filtering element (9) having first and second faces (10, 11) so as to produce filtered liquid (4) having total suspended solids of no more than 10 mg/L. The method comprises cycling the liquid-permeable filtering element through the liquid whereby, in a first position, an area of the first face of the filtering element is subjected to liquid under pressure and a pressure across the filtering element is greater than 0 and less than or equal to 5.9 kPa (60 cmH2O), and, in a second position, the area is not subjected to liquid under pressure or is subjected to liquid at a lower pressure, and solids accumulated on the first face of the filtering element can be removed by directing at least one jet at the second face of the filtering element through the filtering element towards the first face. The filtering element has a pore size and the filtering element is cycled at a speed such that permeation flux is between 200 L/(m2h) to 5,000 L/(m2h) and a thickness of a layer of accumulated solids when removed is between 0 and 6 cm.