Horizontal Plasma Channels for PFAS Destruction
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Solution Overview
Problem
Current plasma treatment systems for contaminant destruction in liquids, particularly those using Enhanced Contact Electrical Discharge Plasma (EDP), face challenges in scaling up due to the need for a gas headspace and lack of efficient configurations for treating highly resistant contaminants like PFAS, which are not effectively removed by traditional methods.
Innovation Solution
A plasma treatment system with multiple horizontal, parallel channels is developed, where each channel has a gas diffuser at the bottom and electrodes submerged in liquid, allowing for stacked configurations and optional recirculation of process gas to reduce the need for diffusers and enhance contaminant destruction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas headspace is used in EDP systems, then plasma generation is enabled, but system scalability is limited
Solution Approach 1:
The system is divided into multiple independent treatment channels that can be stacked vertically. Each channel functions as a separate EDP unit with its own gas diffuser, electrodes, and gas headspace, allowing modular scaling. The multi-channel configuration enables the system to handle larger treatment volumes while maintaining the necessary gas headspace for plasma generation in each channel.
Solution Approach 2:
The invention transitions from a single-channel horizontal configuration to a multi-channel vertical stacking arrangement. By utilizing the vertical dimension, the system achieves scalability without compromising the gas headspace requirement for plasma generation. Multiple channels are arranged in parallel and stacked vertically within a common process tank.
2Productivity
If multiple EDP channels are stacked in a common process tank, then system scalability is improved, but device complexity increases
Solution Approach 1:
Multiple EDP channels are combined within a single common process tank, sharing the same structural envelope and support system. The channels are arranged in parallel and stacked vertically, merging multiple functional units into one integrated system. This approach scales treatment capacity while consolidating structural complexity into a unified design.
3Productivity
If gas diffusers are used in each channel, then contaminant transport to gas/liquid interface is enhanced, but system cost and complexity increase
Solution Approach 1:
The gas diffuser is designed to serve multiple channels simultaneously, acting as a universal component that distributes process gas to multiple treatment zones. This multi-functional approach reduces the total number of diffusers required while maintaining effective contaminant transport to the gas/liquid interface in each channel.
4Productivity
If PFAS contaminants are concentrated before treatment, then treatment efficiency is improved, but additional process steps are required
Solution Approach 1:
The system incorporates a concentration step before the plasma treatment to pre-concentrate PFAS contaminants. This preliminary action enhances the subsequent treatment efficiency by reducing the volume of dilute contaminant stream that requires processing. The concentration step is integrated into the overall process flow, preparing the contaminant stream for more effective plasma degradation.
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 configuration enables scalable and efficient treatment of contaminants like PFAS by creating a gas/liquid interface for plasma generation, allowing for continuous or batch operations and reducing system size and cost by concentrating contaminants before treatment.
Implementation Method 1
a gas diffuser at the bottom of the EDP channel. As water is pumped through the system, argon gas is bubbled through the diffuser, conveying the PFAS to the gas/water interface
Implementation Method 2
The plasma generated by the electrodes destroys the PFAS by breaking the hydrophobic, hydrocarbon chains above the gas/liquid interface
Implementation Method 3
Enhanced Contact Electrical Discharge Plasma (EDP) system
Data Source
AI summary
A system using electrical discharge plasma (EDP) for treating a liquid, such as water or waste water to degrade or destroy polar contaminants such as per- and polyfluoroalkyl substances (PFAS) compounds, the system includes a sealed process tank and multiple submerged EDP channels stacked horizontally. Each EDP channel consists of a cathode and an anode, a gas hood, and a gas diffuser. The basic submerged EDP channel is bounded by a plate at the bottom and a submerged gas hood at the top which creates a gas headspace, and hence, a local water surface to provide a local gas/liquid interface in each channel. The cathode lies above the local water surface and anode lies below the local water surface. Each EDP channel may have a gas diffuser at the bottom of the EDP channel for introducing a process gas into the liquid creating bubbles that carry contaminants in the liquid to the local gas/liquid interface. An electrical discharge arcs between the cathode and the anode to generate a plasma used for destruction of contaminants in the water or wastewater at the local gas/liquid interface.