Membrane Cleaning via Oxidizing and Reducing Agent Neutralization
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Solution Overview
Problem
Current membrane cleaning methods generate significant chemical waste and can damage microbial systems in membrane bioreactors, particularly when chemical cleaning solutions cannot be returned to the treatment plant, leading to increased operating costs and system downtime.
Innovation Solution
A method involving a first cleaning solution with an oxidizing agent, followed by a second solution containing a reducing agent and an enhancing agent, which neutralizes the oxidizing residual and forms an acidic mixed solution to simultaneously remove organic and inorganic foulants from polymeric membranes, reducing waste volume and chemical costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard chemical cleaning methods are used to clean membranes, then membrane cleaning effectiveness is improved, but chemical waste volume and environmental damage increase
Solution Approach 1:
The patent combines the oxidizing cleaning step and the neutralization step into a single integrated process. The second cleaning solution contains both a reducing agent (for neutralization) and cleaning agents, allowing simultaneous neutralization of residual oxidizing agents and continued cleaning action. This merging eliminates the need for separate neutralization and cleaning steps, reducing chemical waste volume while maintaining cleaning effectiveness.
Solution Approach 2:
The patent converts the harmful residual oxidizing agents into beneficial cleaning action. By introducing a reducing agent that reacts with residual oxidizing agents to form acidic species, the harmful residuals are transformed into acidic cleaning agents that continue to clean the membrane. This converts a potentially harmful byproduct into a useful cleaning mechanism, reducing waste while maintaining or enhancing cleaning effectiveness.
2Reliability
If chemical cleaning solutions are discharged to clean membranes, then membrane fouling is removed, but microbial systems in membrane bioreactors are damaged
Solution Approach 1:
The patent introduces a second cleaning solution as an intermediary that performs dual functions: neutralizing residual oxidizing agents and providing continued cleaning action. This intermediary solution bridges the gap between effective membrane cleaning and protection of microbial systems by ensuring complete neutralization of harsh chemicals while maintaining cleaning effectiveness through its own cleaning agents.
Solution Approach 2:
The patent changes the chemical parameters of the cleaning process by transitioning from a strongly oxidizing environment to a controlled acidic environment through the addition of reducing agents. This parameter change neutralizes the harmful effects on microbial systems while maintaining cleaning effectiveness through the acidic species formed during neutralization and the additional cleaning agents in the second solution.
3Reliability
If multiple separate cleaning solutions are used to neutralize and clean, then cleaning thoroughness is improved, but process complexity and operating costs increase
Solution Approach 1:
The patent merges multiple functions into a single second cleaning solution: neutralization of residual oxidizing agents, continued cleaning of membrane surfaces, and adjustment of pH levels. This consolidation reduces process complexity by eliminating separate neutralization and cleaning steps while maintaining thoroughness through the combined actions of reducing agents, acidic species, and additional cleaning agents in the unified solution.
Solution Approach 2:
The second cleaning solution is designed with multi-functionality, serving as both a neutralizing agent and a cleaning solution. It contains reducing agents for neutralization, acidic species for cleaning, and additional cleaning agents to ensure thoroughness. This universal solution performs multiple functions that would traditionally require separate steps, reducing operational complexity while maintaining cleaning thoroughness.
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 method achieves effective membrane cleaning with reduced wastewater volume and chemical usage, maintaining membrane efficiency while minimizing the impact on microbial systems, equivalent to standard chemical cleaning protocols but with lower environmental and operational costs.
Implementation Method 1
introducing a first cleaning solution including an oxidising agent to a tank containing the membrane, contacting at least a portion of the membrane with the first cleaning solution
Implementation Method 2
introducing a second cleaning solution including a reducing agent to the tank containing the membrane and the first cleaning solution after the first time period has elapsed to neutralize an oxidizing residual of the first cleaning solution and to form a mixed cleaning solution containing an acid species
Data Source
AI summary
Methods for cleaning polymeric microfiltration or ultrafiltration membranes. The membrane may be contacted with a first cleaning solution including at least one oxidising agent. A second cleaning solution including at least one reducing agent may then be introduced to the membrane and first cleaning solution. The oxidising and reducing agents may undergo a neutralisation reaction to form an oxidation-neutral mixed cleaning solution. The membrane may be simultaneously cleaned during the neutralisation reaction.