Riser Pipe Dewatering Fly Ash Pond with Filter Textile
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Solution Overview
Problem
Fly ash ponds or pits pose challenges due to the instability of fly ash, particularly caused by its fineness and high water content, necessitating effective dewatering for better handling and compliance with regulatory requirements for closure or remediation.
Innovation Solution
A method involving the preparation of wellbores with riser pipes and filter textiles to create a system for dewatering fly ash ponds or pits, using negative pressure to draw water through perforated drain pipes wrapped with porous filter textiles, ensuring clear water extraction and minimizing fly ash entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dewatering is performed using conventional methods, then water extraction is achieved, but fly ash particles enter the extracted water and stability is not sufficiently improved
Solution Approach 1:
The patent employs a filter textile with controlled porosity (apparent opening size of 200 microns or less) wrapped around the drain pipe. This porous material allows water to pass through while blocking fly ash particles, achieving both dewatering and particle separation simultaneously. The specific pore size is optimized to retain fine fly ash particles while maintaining water flow.
Solution Approach 2:
The filter textile acts as an intermediary element between the fly ash pond and the drainage system. It mediates the interaction between water and fly ash particles, allowing beneficial water extraction while preventing harmful particle contamination. The textile serves as a physical barrier that separates the two phases without completely blocking fluid flow.
2Object-generated harmful factors
If fine filter materials are used to prevent fly ash particles from entering water, then particle separation improves, but water flow and dewatering efficiency decrease
Solution Approach 1:
The filter textile is specifically engineered with an apparent opening size of 200 microns or less, which is optimized to balance particle retention and water flow. This pore size is small enough to capture fine fly ash particles but large enough to maintain adequate water permeability, thus resolving the contradiction between filtration effectiveness and dewatering efficiency.
Solution Approach 2:
The patent specifies a particular parameter range for the filter textile (apparent opening size ≤200 microns) that optimizes the balance between particle retention and water flow. By controlling this critical parameter, the system achieves both effective particle separation and maintained dewatering productivity.
3Quantity of substance
If large quantities of fly ash are handled, then disposal capacity increases, but instability and handling difficulty increase
Solution Approach 1:
The patent extracts water from the fly ash pond through the riser pipe and filter textile system. By removing the water component, the system concentrates the fly ash and improves its stability, making large quantities of fly ash easier to handle and more suitable for disposal or remediation operations.
Solution Approach 2:
The system uses hydraulic principles to generate negative pressure within the riser pipe, which draws water from the fly ash pond through the filter textile. This hydraulic mechanism enables efficient water extraction from large volumes of fly ash, facilitating dewatering of substantial quantities while improving stability.
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 method effectively dewatering fly ash ponds or pits, resulting in increased stability and compliance with regulatory requirements by extracting visibly clear water, thereby facilitating better handling and management of fly ash.
Implementation Method 1
a filter textile wrapped about the drain pipe so as to at least overlap the perforations, the filter textile being porous with openings having apparent opening size of 200 microns or less
Implementation Method 2
generating negative pressure within the riser pipe so as to draw water from adjacent the first wellbore and through the filter textile
Data Source
AI summary
A method is provided herein of dewatering a fly ash pond or pit, the method including: preparing one or more wellbores in, or in proximity to, the fly ash pond or pit; installing a riser pipe into a first of the wellbores, the riser pipe including a drain pipe having perforations formed therethrough, and a filter textile wrapped about the drain pipe so as to at least overlap the perforations, the filter textile being porous with openings having apparent opening size of 200 microns or less; and, generating negative pressure within the riser pipe so as to draw water from adjacent the first wellbore and through the filter textile. Advantageously, the method of the subject invention allows for the dewatering of a fly ash pond or pit with extraction of water therefrom which is visibly clear.