C4-HSL Signal Molecules for Low-Temperature Nitrogen Removal

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Solution Overview

Problem

Existing sewage treatment methods face challenges in maintaining effective biological nitrogen removal at low temperatures due to microbial sensitivity, high costs of heat insulation and equipment modification, and the complexity of using long-chain acyl homoserine lactones (AHLs) signal molecules, which are difficult to dissolve and store.

Innovation Solution

The use of a cost-effective exogenous acyl homoserine lactones (AHLs) signal molecule, specifically N-butanoyl-L-homoserine lactone (C4-HSL), is introduced to intervene in the quorum sensing phenomenon among microorganisms in low-temperature systems, enhancing nitrogen removal performance and reducing mixed liquor suspended solids (MLSS) in activated sludge processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heat insulation or heating measures are adopted to eliminate the impact of low temperature on biological nitrogen removal, then nitrogen removal efficiency is improved, but construction and operation costs increase significantly

Engineering Contradiction:
Improvenitrogen removal efficiencyVSAvoidconstruction and operation costs
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent changes the chemical parameters of the system by introducing exogenous AHLs signal molecules to alter microbial behavior and activate quorum sensing pathways, enabling low-temperature nitrogen removal without changing the physical temperature parameter through heating or insulation measures

Inventive Principle:
Principle #35Parameter changes

2Reliability

If treatment equipment is modified to improve low-temperature performance, then nitrogen removal efficiency is improved, but construction costs increase and implementation is limited in existing plants

Engineering Contradiction:
Improvenitrogen removal efficiencyVSAvoidimplementation feasibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces AHLs signal molecules as intermediaries that mediate between the low-temperature environment and the microbial community, enabling the existing treatment equipment to function effectively at low temperatures without any structural modification

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If low-temperature microbial inoculant is added to improve nitrogen removal at low temperatures, then nitrogen removal efficiency is improved, but screening process becomes complex and acclimation time increases

Engineering Contradiction:
Improvenitrogen removal efficiencyVSAvoidacclimation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent enables the existing microbial community to self-adjust and activate low-temperature functionality by responding to AHLs signal molecules, eliminating the need for external low-temperature inoculants and their associated screening and acclimation processes

Inventive Principle:
Principle #25Self-service

4Reliability

If microbial inoculant is inoculated to improve low-temperature nitrogen removal, then nitrogen removal efficiency is improved, but local bacteria are competed against causing loss of bacterial strains

Engineering Contradiction:
Improvenitrogen removal efficiencyVSAvoidbacterial strains
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent introduces AHLs signal molecules that create a feedback mechanism within the existing microbial community, stimulating quorum sensing and cooperative behavior among native bacteria to maintain diversity while improving low-temperature nitrogen removal performance

Inventive Principle:
Principle #23Feedback

5Speed

If mixed AHLs-like signal molecules are used for rapid start-up at low temperatures, then start-up speed is improved, but solubility decreases and storage costs increase

Engineering Contradiction:
Improvereactor start-up speedVSAvoidstorage and transportation costs
Core Design Contradiction:
SpeedVSUse of energy by stationary object

Solution Approach 1:

The patent extracts and uses only the essential short-chain AHLs signal molecules (C4-HSL, C6-HSL, C8-HSL) that provide the necessary quorum sensing activation, eliminating the need for complex mixed formulations and their associated solubility and storage problems

Inventive Principle:
Principle #2Taking out (Extraction)

6Speed

If common AHLs signal molecules are used for rapid start-up, then start-up speed is improved, but cost increases and process complexity increases

Engineering Contradiction:
Improvereactor start-up speedVSAvoidprocess complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent segments the AHLs signal molecules by chain length and selectively applies only the short-chain variants (C4-HSL, C6-HSL, C8-HSL) that are water-soluble and cost-effective, simplifying the overall process while maintaining rapid start-up capability

Inventive Principle:
Principle #1Segmentation

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 C4-HSL molecule improves nitrogen removal efficiency, promotes microbial activity, and reduces sludge amounts, achieving stable operation and cost-effectiveness in low-temperature sewage treatment, even under sudden cooling conditions, while being easier to store and handle compared to other AHLs.

Implementation Method 1

adding an exogenous signal molecule. The signal molecule can intervene in a QS phenomenon among microorganisms in a low-temperature system to be treated

Methodology Applied
Scientific EffectQuorum sensing:

Data Source

PatentUS20240262727A1Method for improving biological nitrogen removal effect of low-temperature sewage
Publication Date: 2024.08.08 SICHUAN UNIV

AI summary

The present disclosure provides a method for improving a biological nitrogen removal effect of low-temperature sewage, and relates to the technical field of sewage treatment. In the present disclosure, the method is implemented by adding an exogenous signal molecule. The exogenous signal molecule can intervene in a quorum sensing (QS) phenomenon among microorganisms, and can also reduce mixed liquor suspended solids (MLSS), reduce an amount of remaining sludge, and reduce a cost of sludge treatment while effectively improving the low-temperature nitrogen removal effect.