Compressible Medium Filter Backwash Using Self-Compression
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Solution Overview
Problem
Conventional tertiary wastewater filters, including compressible medium filters, require additional mechanical devices for compression, increasing complexity and capital expenses, while struggling to meet stringent total suspended solids (TSS) and turbidity discharge limits effectively.
Innovation Solution
A synthetic compressible medium filter system that uses a method comprising three sequences: air and water wash, air purge, and medium compression, triggered by pressure, time, or turbidity set points, eliminating the need for external compression machinery by utilizing fluid flow to compress the medium, thereby enhancing filtration efficiency and reducing operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If compressible medium filters use mechanical devices to compress the medium, then filtration loading rate is improved, but device complexity and capital expense increase
Solution Approach 1:
The filter medium compresses itself under the weight of the accumulated filtered material (cake layer) during operation, eliminating the need for external mechanical compression devices. The system uses its own operational conditions to achieve the compression effect automatically
Solution Approach 2:
The patent replaces mechanical compression devices with a gravity-based self-compression mechanism. The filtered material accumulation creates sufficient pressure to compress the medium without requiring motors, hydraulics, or mechanical press systems
2Reliability
If compressible medium filters use mechanical compression devices, then filtration efficiency is improved, but capital expense increases
Solution Approach 1:
The filter medium achieves the required compression and filtration efficiency through self-compression by the accumulated cake weight during normal operation, eliminating capital expenditure on external compression machinery while maintaining effective filtration performance
Solution Approach 2:
The patent uses inexpensive synthetic filter media that can be replaced periodically, eliminating the need for expensive mechanical compression systems. The focus shifts from expensive durable mechanical components to affordable consumable filter elements
3Device complexity
If conventional filters use cloth or granular media, then structure is simple, but filtration rate is limited
Solution Approach 1:
The patent changes the physical parameters of the filter medium by using compressible synthetic materials that can dynamically adjust their porosity and density. This allows the medium to transition between high-flow states and high-filtration states, achieving both simplicity and high filtration rates
Solution Approach 2:
The invention uses composite filter media combining synthetic fibers with compressible properties, creating a material that integrates the structural simplicity of traditional media with the high-performance characteristics of advanced materials, enabling superior filtration rates without mechanical complexity
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 filtration rates up to 40 gpm/ft2 with effluent TSS < 5 mg/L and turbidity < 2 NTU, meeting stringent discharge requirements without additional mechanical complexity, and reduces water usage in backwashing to less than 7% of treated volume.
Implementation Method 1
introducing air into the medium, causing bubbles which carry at least some of the media to the top of the filter, at which point the air escapes from the filter and the media sinks downward, striking media ascending with air bubbles
Implementation Method 2
using water and air flow to generate forces to break the medium free from a compressed stage
Implementation Method 3
the backwash water and introduced raw water provide enough energy to compress the medium without introduction of air into the medium
Data Source
AI summary
The invention is directed to methods of providing backwash processes for a synthetic compressible medium filter system. More specifically, the system may include a backwash pump and air blower, and the processes may include at least three sequences of: air and water wash; air purge; and medium compression. The backwash process may be triggered by one or more of a pressure, time point, and/or turbidity set point. The air and water wash sequence may include breaking and washing the medium. The air purge sequence may include removing substantially all of the air entrapped in the medium by providing a backwash water flow for a period of time; and a medium compression sequence compressing the medium while avoiding exposing the medium to air, including introducing raw water and where the backwash and raw water provide enough energy to compress the medium without introduction of air into the medium.