Gas Diffusion Sizing Using Tracer Gases for Groundwater Remediation

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Solution Overview

Problem

Current in situ groundwater remediation technologies face challenges such as high costs, environmental impact, inefficiencies, and inaccurate sizing methods due to limitations in gas diffusion monitoring and pollutant identification, particularly in Italy, where traditional methods rely on discrete data points and struggle with biofouling and energy consumption.

Innovation Solution

A method utilizing a gas mixture with a 'useful' gas for remediation and inert tracer gases to monitor and size gas diffusion systems, allowing for more accurate data collection and real-time monitoring of pollutant presence and groundwater movement, enhancing the efficiency and precision of remediation processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If Air-Sparging is used to treat groundwater, then oxygen dissolution in groundwater is improved, but stripping processes of volatile substances increase and energy consumption rises

Engineering Contradiction:
Improveoxygen concentration in groundwaterVSAvoidstripping phenomena of volatile substances
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent changes the gas composition parameter from air (21% oxygen) to pure oxygen or oxygen-enriched gas, thereby increasing oxygen dissolution efficiency while reducing gas flow rates needed, which in turn minimizes stripping of volatile contaminants

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs specialized diffusion equipment including hollow polymeric membranes that enable controlled gas-liquid exchange, improving oxygen transfer efficiency while minimizing bubble formation and associated stripping effects

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Quantity of substance

If hollow polymeric membranes are used for oxygen diffusion, then gas dissolution efficiency is improved, but biofouling phenomena cause membrane blinding and efficiency loss

Engineering Contradiction:
Improveoxygen dissolution efficiencyVSAvoidmembrane efficiency over time
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent extracts the diffusion function from the membrane itself and relocates it to the groundwater flow path, allowing oxygen diffusion to occur in the bulk water rather than through membrane surfaces that are susceptible to biofouling

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses simple diffuser elements that can be easily replaced or cleaned, avoiding the need for expensive, fragile hollow membranes that require protection from biofouling

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If discrete sampling points are used for site characterization, then measurement cost is reduced, but measurement precision and completeness of pollutant identification deteriorate

Engineering Contradiction:
Improvesampling system complexityVSAvoidpollutant concentration accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses tracer gases that simultaneously serve multiple functions: characterizing groundwater flow paths, identifying pollutant locations, and monitoring remediation progress, thereby obtaining comprehensive site information without increasing sampling complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces tracer gases as intermediary substances that reveal information about groundwater movement and pollutant distribution indirectly, allowing comprehensive site characterization without direct sampling of all contaminants

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach provides more precise data for system sizing and real-time monitoring of gas diffusion, identifying previously unnoticed pollutants and fluctuations, leading to improved remediation efficiency and reduced costs by optimizing gas usage and system design.

Implementation Method 1

The propagation difference between a gas useful for remediation and another gas and/or gases, which do not chemically or biologically react with the aquifer

Methodology Applied
Scientific EffectGas diffusion: Diffusion

Implementation Method 2

Gas diffusion phenomena can be increased thanks to high concentration gradients, moreover gas flows can be reduced with respect to the air, thus decreasing stripping processes of volatile substances present in groundwater

Methodology Applied
Scientific EffectGas dissolution: Absorption (physical)

Data Source

PatentEP1914015B1Method based on the use of a gas mixture for sizing systems of gas diffusion in groundwater and evaluating the aquifer contamination
Publication Date: 2016.08.24 SOCIETA ITALIANA ACETILENE & DERIVATI SIAD SPA IN ABBREVIATED FORM SIAD SPA

AI summary

A method introducing improving elements compared with those used at present is disclosed, based on use of gas mixtures in order to size a system of gas diffusion in groundwater. Such a method allows to more precisely define the influence radius of an injection system, the real gas consumption and the time required for reclamation. The method is based on the propagation difference between a gas useful for remediation and an other gas and/or gases, which do not chemically or biologically react with the aquifer. The method allows to overcome the difficulties met at present during the sizing of an injection system of gas in groundwater. The techniques used till now have two important drawbacks: the first one is that they are based on punctual data, while the site of reclamation is a continuous system; the second one is that they are based on the partial analysis of the real chemical composition of contaminated groundwater.