Stabilized Oxidant Biocide Control in Paper Mill Process Water

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Solution Overview

Problem

Stabilized oxidant biocides in commercial process systems can become ineffective due to the presence of organisms that degrade the stabilizers, leading to increased microbial growth and chlorine demand, which reduces the treatment's effectiveness and requires higher chlorine usage.

Innovation Solution

A post-treatment strategy involving non-oxidizing biocides like dibromonitrilopropionamide (DBNPA) and glutaraldehyde, or sodium hypochlorite/inorganic chloramine, is used to neutralize stabilizer-degrading organisms, maintaining the antimicrobial effectiveness of the system without harming the stabilized oxidant composition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If stabilized oxidant biocides are used to control microorganisms, then antimicrobial effectiveness is improved and duration of action is extended, but organisms that degrade stabilizers emerge leading to reduced reliability

Engineering Contradiction:

Improveduration of antimicrobial actionVSAvoidreliability of antimicrobial control

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The treatment is divided into two sequential phases: first applying a stabilized oxidant biocide for extended duration control, then following with a non-oxidizing biocide to eliminate stabilizer-degrading organisms. This segmentation allows each biocide type to address specific aspects of microbial control without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stabilized oxidant biocide is applied first to establish extended antimicrobial control and suppress microbial growth. This preliminary action creates conditions that prevent the emergence of problematic organisms, and if they do emerge, the subsequent non-oxidizing biocide is ready to address them.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If higher chlorine usage is increased to maintain effectiveness, then antimicrobial control is improved, but chlorine demand increases and process efficiency decreases

Engineering Contradiction:

Improvereliability of antimicrobial controlVSAvoidchlorine demand

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

A non-oxidizing biocide acts as an intermediary agent that specifically targets and eliminates stabilizer-degrading organisms without consuming oxidants. This mediator restores the effectiveness of the stabilized oxidant system by removing the organisms that would otherwise consume chlorine and reduce control reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Duration of action of stationary object

If stabilized oxidants are used to suppress microorganisms, then duration of action is extended, but stabilizer-degrading organisms emerge reducing treatment effectiveness

Engineering Contradiction:

Improveduration of biocide effectivenessVSAvoidstabilizer degradation

Core Design Contradiction:

Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The emergence of stabilizer-degrading organisms, which initially appears harmful by reducing treatment effectiveness, is converted into a benefit by using these organisms as targets for the non-oxidizing biocide. The sequential application transforms the problem of organism emergence into an opportunity for precise, targeted control that eliminates the harmful organisms while preserving the stabilized oxidant system.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 prevents the rise of organisms that degrade oxidant stabilizers, ensuring sustained antimicrobial control and reducing chlorine demand, thus maintaining process efficiency and product quality.

Implementation Method 1

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

Oxidants, such as sodium hypochlorite, are highly reactive and effectively 'burn' away the cell walls of many microorganisms

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 3

By stabilizing oxidants, the oxidant remains present in the system for a longer period of time and is capable of suppressing microorganisms for an extended period of time

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentEP2912188B1Method to control bacteria tolerant to stabilized-oxidant treatment in process water of paper mills

Publication Date: 2020.08.26 NALCO CO

AI summary

The invention provides for treatment strategies that prevent or control the growth of organisms that degrade oxidant stabilizers in oxidant stabilized biocides. This allows stabilized halogen programs to perform at their intended level and prevents the need for increased halogen usage in an attempt to maintain control of these microbial populations and reduce the halogen-demand created by their enzyme byproducts.