Asynchronous Chlorine Dioxide Dosing for Microbial Adaptation Control

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Solution Overview

Problem

Existing methods for controlling biological fouling in industrial water systems, particularly those using oxidizing biocides, are ineffective in waters with high chlorine demand and can lead to microbial adaptation, necessitating new approaches to prevent bacterial growth and maintain system efficiency and safety.

Innovation Solution

A method involving asynchronous feeding of acid and chlorate salt into a diluent stream or tank to create a fluctuating chlorine dioxide concentration, which is then injected into process water, utilizing a 'slug dose' strategy and potentially including hydrogen peroxide, to effectively kill organisms and prevent adaptation, while avoiding 'runaway' reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional oxidizing biocides are used to control biological fouling, then disinfection effectiveness is improved, but microbial adaptation occurs and system reliability deteriorates

Engineering Contradiction:
Improvedisinfection effectivenessVSAvoidmicrobial adaptation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system uses periodic pulse dosing of chlorine dioxide instead of continuous dosing, creating fluctuating concentration cycles that prevent microbial adaptation while maintaining disinfection effectiveness. The pulse generator creates periodic spikes in biocide concentration that disrupt biofilm formation and kill adapted organisms.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention implements dynamic concentration control where the chlorine dioxide concentration varies over time rather than remaining constant. This dynamic approach, through automated pulse dosing based on flow rate and contact time calculations, prevents microbes from adapting to a steady-state biocide level.

Inventive Principle:
Principle #15Dynamics

2Reliability

If high doses of biocides are applied to kill microorganisms, then disinfection effectiveness is improved, but harmful side effects increase due to chemical accumulation

Engineering Contradiction:
Improvedisinfection effectivenessVSAvoidchemical accumulation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Periodic pulse dosing delivers high biocide concentrations in short bursts followed by lower concentration periods, achieving effective disinfection while allowing chemical levels to回落 between pulses, preventing harmful accumulation in the water system.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system applies excessive biocide dosage temporarily during pulse events to ensure complete microbial kill, then reduces dosage during inter-pulse periods, achieving effective disinfection with lower overall chemical accumulation than continuous high-dose application.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If continuous biocide dosing is used to maintain disinfection, then reliability is improved, but device complexity increases due to constant monitoring and adjustment requirements

Engineering Contradiction:
Improvedisinfection effectivenessVSAvoiddosing system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses flow rate sensors and automated calculations to self-determine appropriate pulse dosing parameters based on real-time water flow conditions, eliminating the need for complex continuous monitoring and manual adjustment mechanisms while maintaining reliable disinfection.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates flow rate sensing and automated feedback control where the pulse dosing frequency and magnitude are automatically adjusted based on measured water flow characteristics, simplifying the control system compared to continuous dosing while maintaining effective disinfection.

Inventive Principle:
Principle #23Feedback

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 method provides a dynamic chlorine dioxide concentration that effectively kills microorganisms and creates an environment resistant to bacterial growth, enhancing system efficiency and safety by preventing microbial adaptation and maintaining a stable operational state.

Implementation Method 1

The reaction of the alkali salts of chlorite and chlorate and acid produces chlorine dioxide in-situ in the water of the industrial water system

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

The chlorine dioxide kills microorganisms

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

a water flow-proportional, fluid proportioning device having three or more fluid transferring devices

Methodology Applied
Scientific EffectFluid flow proportioning: Fluid Spray

Data Source

PatentEP3585738B1Method for onsite production of chlorine dioxide
Publication Date: 2024.08.14 ECOLAB USA INC
  • EP3585738B1 patent drawingFigure 1
  • EP3585738B1 patent drawingFigure 2
  • EP3585738B1 patent drawingFigure 3

AI summary

The methods disclosed generally relate to treatment of process water using chlorine dioxide. Specifically, reactants may be fed asynchronously into a diluent line or a tank where the reactants may mix and react to form chlorine dioxide. The chlorine dioxide levels may fluctuate in the diluent line or the tank thereby inhibiting or reducing the growth of microbes.