Sodium Bisulfite Chelation for VFA Control in Papermaking
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Solution Overview
Problem
Papermaking systems face challenges in controlling volatile fatty acids (VFA) and bacteria that produce them, leading to undesirable odors and organic gas production, particularly in broke chests with poor microbial control.
Innovation Solution
The use of chelants such as sodium bisulfite and ethylenediamine tetraacetic acid (EDTA) as control agents in aqueous industrial systems to inhibit the formation and growth of VFA-producing bacteria, binding metal ions in the bacteria's cell walls and preventing VFA production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-oxidizing biocides are added to broke chests to control microbial growth, then microbial control is improved, but VFA-producing bacteria still proliferate and produce odorous fermentation products
Solution Approach 1:
The patent changes the chemical parameter of the water system by adding sulfite (SO2) to create a reducing environment. This parameter change specifically targets anaerobic bacteria's metabolic pathways, inhibiting their ability to produce VFA while allowing aerobic bacteria to thrive, thus resolving the contradiction between microbial control and VFA prevention
Solution Approach 2:
The patent converts the harmful effect of sulfite (which can be detrimental to paper quality) into a beneficial effect by using it specifically to control anaerobic bacteria. The sulfite creates conditions that favor aerobic bacteria over anaerobic ones, transforming a potential harm into a selective biological control mechanism that prevents VFA production
2Reliability
If broke chests are sealed to prevent contamination, then microbial introduction is reduced, but anaerobic conditions promote VFA-producing bacteria growth
Solution Approach 1:
The patent changes the redox parameter of the sealed system by introducing sulfite, which creates a chemically reducing environment. This parameter change allows the system to remain sealed (preventing contamination) while simultaneously creating conditions unfavorable for anaerobic bacteria through chemical rather than physical means
Solution Approach 2:
The patent introduces sulfite as a chemical intermediary that mediates between the sealed environment and the bacterial population. The sulfite acts as a selective agent that differentially affects aerobic and anaerobic bacteria, allowing the system to maintain both seal integrity and biological control
3Reliability
If oxidizing biocides are used to control bacteria, then general microbial growth is inhibited, but they fail to prevent VFA-producing facultative anaerobes
Solution Approach 1:
The patent inverts the conventional biocidal approach by using a reducing agent (sulfite) instead of an oxidizing agent. This inversion specifically targets facultative anaerobes by creating conditions that expose their metabolic vulnerability, while simultaneously protecting aerobic bacteria, thus achieving selective control that conventional biocides cannot provide
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
Significantly reduces the concentration of VFA-producing bacteria and inhibits VFA formation by up to 100%, effectively eliminating or substantially reducing VFA in papermaking process water and products, improving microbial control and odor management.
Implementation Method 1
The use of chelants such as sodium bisulfite and ethylenediamine tetraacetic acid (EDTA) as control agents in aqueous industrial systems to inhibit the formation and growth of VFA-producing bacteria, binding metal ions in the bacteria's cell walls and preventing VFA production
Implementation Method 2
The use of chelants such as sodium bisulfite and ethylenediamine tetraacetic acid (EDTA) as control agents in aqueous industrial systems to inhibit the formation and growth of VFA-producing bacteria, binding metal ions in the bacteria's cell walls and preventing VFA production
Data Source
AI summary
The present disclosure provides compositions and methods for treating volatile fatty acids and bacteria capable of producing volatile fatty acids. The compositions can convert acid-producing bacteria environments to nitrate-reducing bacteria environments. The compositions and methods can lower the amount of acid-producing bacteria present in the environment and thereby reduce the amount of volatile fatty acids present in the environment. The control agent may also inhibit the growth of acid-producing bacteria and volatile fatty acid concentrations. The compositions and methods can be used with any aqueous industrial system.