Membrane Contactor Carbon Booster for Low-Cost Denitrification
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Solution Overview
Problem
Existing biological denitrification processes face challenges with low carbon-nitrogen ratios in sewage, reliance on expensive carbon sources, and instability of hydrolytic fermentation bacteria, leading to high costs and inefficiencies.
Innovation Solution
A device comprising an anoxic tank, aerobic tank, and carbon source booster with membrane contactors that facilitate hydrolytic fermentation of macromolecular carbon sources into volatile fatty acids, enhancing denitrification by increasing contact time and area, and reducing redox potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If additional carbon sources (such as methanol, glucose, sodium acetate) are added to achieve denitrification in low carbon-nitrogen ratio sewage, then denitrification efficiency is improved, but the cost of chemicals increases
Solution Approach 1:
The system utilizes endogenous carbon sources from waste activated sludge through hydrolytic fermentation, allowing the treatment process to serve itself by converting its own byproducts (sludge) into useful carbon sources for denitrification, eliminating the need for external chemical additions
Solution Approach 2:
The invention changes the carbon source from external chemicals to internally generated volatile fatty acids through controlled hydrolytic fermentation, transforming the parameter of carbon source origin from exogenous to endogenous, thereby reducing chemical costs while maintaining denitrification efficiency
2Productivity
If rapidly biodegradable carbon sources (such as acetic acid or sodium acetate) are used for denitrification, then denitrification efficiency is improved, but the stability of microbial populations deteriorates
Solution Approach 1:
The system produces a composite mixture of multiple volatile fatty acids (acetic acid, propionic acid, butyric acid, etc.) through hydrolytic fermentation, creating a complex carbon source composition that supports diverse microbial populations and enhances system stability compared to single-component carbon sources
3Quantity of substance
If hydrolytic fermentation bacteria are used to convert macromolecular organic matter into volatile fatty acids, then carbon source quality is improved, but the bacteria are difficult to enrich and easy to lose
Solution Approach 1:
The invention combines the hydrolytic fermentation process with the existing waste activated sludge system, merging the function of carbon source production with the wastewater treatment process itself, thereby stabilizing the bacterial population within an established system rather than attempting to maintain separate bacterial cultures
Solution Approach 2:
The system uses waste activated sludge as an intermediary substrate that contains the necessary hydrolytic fermentation bacteria, allowing these bacteria to be maintained indirectly through the continuous presence of their natural habitat (sludge) rather than requiring direct bacterial inoculation and maintenance
4Productivity
If membrane contactors are used to increase contact time and area between sewage and carbon source, then denitrification effect is improved, but device complexity increases
Solution Approach 1:
The system employs a membrane contactor that utilizes hydraulic flow to increase contact time and surface area between the carbon source and sewage, using fluid dynamics rather than mechanical agitation or complex mixing mechanisms to achieve enhanced mass transfer and denitrification
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 solution effectively utilizes low-cost macromolecular carbon sources, stabilizes hydrolytic fermentation bacteria, and enhances denitrification efficiency by producing short-chain fatty acids, achieving better nitrogen removal rates and reducing operational costs.
Implementation Method 1
The membrane can facilitate a slow-release diffusion and reduce the redox potential, so as to improve the effect of a nitrogen removal by denitrification
Implementation Method 2
the hydrolysis refers to the enzymatic hydrolysis reaction of macromolecular organic matter outside the cell, and the complex macromolecular organic matter is decomposed into small molecular organic matter
Implementation Method 3
During the acidification, small organic matter is further converted into volatile fatty acids
Implementation Method 4
The membrane can facilitate a slow-release diffusion and reduce the redox potential, so as to improve the effect of a nitrogen removal by denitrification
Data Source
AI summary
The invention discloses a method for enhanced denitrification and a device thereof. The device comprises an anoxic tank, an aerobic tank and a carbon source booster connected in sequence, and an output end of the carbon source booster is then connected with the anoxic tank; a plurality of membrane contactors are fixed inside the carbon source booster, the membrane contactor is in a hollow structure, and there is a gap between the membrane contactors and a shell of the carbon source booster. By adopting the device, macromolecular carbon source can be added and hydrolyzed into volatile fatty acids by using the hydrolytic fermentation bacteria existing in the gap between the carbon source booster and the membrane contactors, which then penetrates into the hollow part of the membrane contactors through membrane diffusion, as a small molecular carbon source that can be effectively used by denitrifying bacteria to promote the denitrification process.