Rapid Leaching and Dewatering for PFAS Soil Remediation
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Solution Overview
Problem
Current remediation techniques for PFAS-contaminated soil are limited, costly, and inefficient, often resulting in labor-intensive processes, significant site preparation, and the need for landfill space, with existing technologies showing limited success in remediating PFAS due to their persistent chemical bonds.
Innovation Solution
A rapid leaching and dewatering system that utilizes a containment pond and filtration system to saturate contaminated soil with water, allowing contaminants to partition into a liquid phase, which is then treated, while the cleaned soil is rapidly dewatered and reused or disposed of.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional soil washing is used to remove PFAS from soil, then contaminants are removed from soil, but the process is labor and power intensive, requires significant site preparation, and produces sludge that must be exported and clean backfill imported
Solution Approach 1:
The patent extracts the washing process from complex mechanical soil washing equipment and simplifies it to a containment pond system where water is added to saturate soil, allowing contaminants to partition into the liquid phase which is then removed. This eliminates the need for complex mechanical mixing, separation equipment, and extensive site preparation while achieving contaminant removal.
Solution Approach 2:
The patent introduces water as an intermediary substance that facilitates contaminant removal by partitioning PFAS from soil into the liquid phase. This intermediary approach avoids direct mechanical removal methods and enables simple dewatering to separate clean soil from contaminated water, eliminating the need for complex mechanical separation equipment.
2Quantity of substance
If excavation and disposal of PFAS impacted soil at a Subtitle C landfill is used, then contaminants are removed from the environment, but it is extremely costly and removes precious landfill space for future use
Solution Approach 1:
The patent extracts and removes only the liquid phase containing dissolved contaminants from the soil matrix, leaving the solid soil particles intact and reusable. This selective extraction approach eliminates the need to dispose of entire volumes of contaminated soil at landfills, preserving landfill space while achieving environmental remediation.
Solution Approach 2:
The patent discards only the contaminated water phase while recovering and reusing the clean soil. The dewatering process separates the liquid contaminant phase from the solid soil phase, allowing the soil to be returned to service or reused, thereby avoiding the loss of valuable landfill space that would occur if entire soil volumes were disposed of.
3Reliability
If current PFAS treatment technologies are used on contaminated soil, then treatment is attempted, but effectiveness is limited due to strong carbon-fluorine bonds making degradation challenging
Solution Approach 1:
The patent converts the persistent nature of PFAS bonds, which resist degradation, into a benefit by using partitioning rather than degradation. Instead of attempting to break the strong carbon-fluorine bonds through challenging degradation processes, the system exploits the fact that PFAS will partition into the liquid phase during saturation, enabling effective removal without needing to overcome bond strength barriers.
Solution Approach 2:
The patent changes the approach from chemical degradation (attempting to break bonds) to physical partitioning (changing phase distribution). By altering the system from a degradation-focused process to a partitioning-focused process using water saturation and dewatering, the method achieves effective contaminant removal without being constrained by the strength of carbon-fluorine bonds.
4Productivity
If rapid dewatering is implemented to remove water from saturated soil, then contaminants are separated from soil, but energy and time are required for the dewatering process
Solution Approach 1:
The patent segments the separation process into distinct phases: water addition for saturation, contaminant partitioning into liquid phase, and dewatering for separation. This segmentation allows each step to be optimized independently, with dewatering being the final rapid separation step that achieves quick contaminant removal without requiring prolonged processing time for the entire system.
Solution Approach 2:
The patent rushes through the dewatering process by using gravity-driven drainage and filtration systems that rapidly remove water from saturated soil. This approach minimizes the time required for the separation step while maintaining effective contaminant removal, allowing quick turnover and high productivity without excessive energy input or time consumption.
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 effectively reduces or eliminates PFAS and other contaminants from soil, reducing the risk of leaching into groundwater or surface water, and provides a cost-effective, sustainable, and scalable solution for soil remediation, improving land, sediment, surface water, and groundwater quality.
Implementation Method 1
allowing contaminants to partition into a liquid phase
Implementation Method 2
filtration system to saturate contaminated soil with water, allowing contaminants to partition into a liquid phase, which is then treated, while the cleaned soil is rapidly dewatered
Data Source
AI summary
The invention provides a rapid leaching and dewatering system for the remediation of PFAS-contaminated solid matrix material (e.g., soil, sediment, and/or sludge material) for the removal of PFAS compounds, and other contaminants, therefrom. The system mobilizes contaminants from a solid state (soil/sediment/sludge) to a liquid state resulting in a clean solid material.