Porous Membrane Gas Diffusion for Groundwater Decontamination

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Solution Overview

Problem

Current groundwater remediation technologies, such as Pump & Treat and Air-Sparging, are costly, environmentally impactful, and inefficient due to high energy consumption, biofouling, and the need for extensive infrastructure, while in situ technologies like ISOC and ORC face limitations in oxygen diffusion and biofouling, leading to prolonged remediation times and increased costs.

Innovation Solution

A gas injection system utilizing a porous microstructured membrane for in situ gas diffusion, which eliminates the need for electric energy, reduces biofouling, and achieves high gas concentrations, allowing for efficient oxidation or reduction processes without waste production, using gases like oxygen, ozone, hydrogen, or methane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If Air-Sparging is used to treat groundwater, then oxygen dissolution in groundwater is achieved, but stripping processes occur and volatile substances are lost

Engineering Contradiction:
Improveoxygen concentration in groundwaterVSAvoidvolatile substances stripping
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent uses a porous diffuser element that allows controlled gas dissolution into groundwater. The porous structure provides large surface area for gas-liquid contact, enabling efficient oxygen transfer while preventing excessive gas flow that would cause stripping of volatile contaminants.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The system controls gas flow parameters to optimize oxygen dissolution while minimizing stripping. By adjusting gas flow rate and pressure through the porous diffuser, the patent achieves high oxygen concentration (40-60 mgO2/l) without the harmful stripping effects of high-velocity air injection.

Inventive Principle:
Principle #35Parameter changes

2Speed

If compressors are used to inject gas in Air-Sparging, then gas flow is achieved, but electric power and on site installation space are required

Engineering Contradiction:
Improvegas injection rateVSAvoidelectric power requirement and installation infrastructure
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical compressor system with a chemical pressure generation system. Chemical reactions (such as decompression of compressed gas cylinders or chemical pressure vessels) generate the necessary pressure to inject gas through the porous diffuser, eliminating the need for electric compressors and associated infrastructure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If membrane systems are used for oxygen diffusion, then gas dissolution efficiency is improved, but biofouling occurs and membrane blinding is caused

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

Solution Approach 1:

The patent employs disposable porous diffuser elements that are inexpensive and can be easily replaced. These single-use or limited-life porous components provide efficient gas dissolution during their service period and are then discarded, avoiding the long-term reliability issues of permanent membranes that suffer from biofouling and blinding.

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

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 system significantly reduces remediation times, minimizes site impact, avoids biofouling, and achieves high oxygen dissolution efficiency, resulting in cost-effective and efficient groundwater decontamination with low operational and environmental impact.

Implementation Method 1

The diffusion equipment has a great importance on the gas dissolution efficiency. In particular, the more gas-liquid exchange surface increases, the more efficient the oxygen dissolution in groundwater.

Methodology Applied
Scientific EffectGas diffusion: Diffusion

Implementation Method 2

Groundwater decontamination system through in situ injection of oxidant and/or riducent gases

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

Groundwater decontamination system through in situ injection of oxidant and/or riducent gases

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP1914016B1Groundwater decontamination system through in situ injection of oxidant and/or riducent gases
Publication Date: 2015.09.09 SOCIETA ITALIANA ACETILENE & DERIVATI SIAD SPA IN ABBREVIATED FORM SIAD SPA
  • EP1914016B1 patent drawingFigure 1~2
  • EP1914016B1 patent drawingFigure 3
  • EP1914016B1 patent drawingFigure 4

AI summary

A microdiffusion system of oxidising and/or reducing gases in groundwater for contaminated sites reclamation is disclosed. The system does not involve the use of electric power and so it can be applied also in those sites where particular safety precautions are required or where no electric power is available. The application of the system involves an in situ configuration. It is based on a gas diffusion process in groundwater characterised by very high efficiency and significant low flows. Gas is fed as micro bubbles that, through their continuous diffusion in the injection point, allow to reach high dissolved gas concentration in groundwater. In this way the system is able to quickly activate biological and/or chemical degradation process in the aquifer, and thanks to high concentration gradient thus created, it has significant influence radius. The system allows to purify the saturated fraction of ground from contaminated substances by reducing and/or oxidising processes. It has a lot of advantages compared to traditional systems, for example: very low site impact, high use flexibility, absence of stripping of volatile substances, absence of biofouling on gas diffusion surface, no waste production.