Short-chain volatile fatty acid and preparation method thereof

A volatile fatty acid and short-chain technology, which is applied in the field of short-chain volatile fatty acids and their preparation, can solve the problems of low efficiency and yield of short-chain volatile fatty acids, long fermentation time, etc., and achieve simple preparation methods, low operating costs, and high product quality. The effect of high yield

Inactive Publication Date: 2015-03-25
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the defects of low efficiency and yield of short-chain volatile fatty acids and long fermentation time (generally 20 to 30 days) in the prior art, and provide a product with high yield, simple preparation method, energy saving and consumption reduction, and easy operation. The method is low-cost and uses free nitrous acid pretreatment combined with alkaline anaerobic fermentation to treat sludge to produce short-chain volatile fatty acids, and also provides short-chain volatile fatty acids prepared by the aforementioned preparation method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] (1) Preparation of fermentation substrate: Take the primary sludge and residual sludge from the sewage treatment plant and mix them according to the mass ratio of 40%:60% (moisture content is 99.2%, pH=6.8) and put them into a glass container in the laboratory , naturally precipitated at 4°C for 24 hours, and drained the supernatant to obtain a fermentation substrate.

[0034] (2) Pretreatment: Add the fermented substrate and sodium nitrite prepared in step (1) into the anaerobic reactor, and mechanically stir and mix at a temperature of 20±0.1°C at a speed of 120rpm / min for 48 hours , to control the NO in the anaerobic reactor 2 - -N concentration is 200mg NO 2 - -N / L, pH control is 6.0. pass NO 2 - The concentration of -N, pH and temperature calculate the concentration of free nitrous acid to be 0.51mg HNO 2 -N / L.

[0035] (3) Anaerobic fermentation: Inflate nitrogen into the anaerobic reactor to drive oxygen for 10 minutes, then adjust the pH in the anaerobic...

Embodiment 2

[0037] (1) Preparation of fermentation substrate: Take the primary sludge and residual sludge from the sewage treatment plant and mix them according to the mass ratio of 40%:60% (moisture content is 99.2%, pH=6.8) and put them into a glass container in the laboratory , naturally precipitated at 4°C for 24 hours, and drained the supernatant to obtain a fermentation substrate.

[0038] (2) Pretreatment: Add the fermented substrate and sodium nitrite prepared in step (1) into the anaerobic reactor, and mechanically stir and mix at a temperature of 20±0.1°C at a speed of 120rpm / min for 48 hours , to control the NO in the anaerobic reactor 2 - -N concentration is 300mg NO 2 - -N / L, pH control is 6.0. pass NO 2 - The concentration of -N, pH and temperature calculate the concentration of free nitrous acid to be 0.77mg HNO 2 -N / L.

[0039] (3) Anaerobic fermentation: Inflate nitrogen into the anaerobic reactor to drive oxygen for 10 minutes, then adjust the pH in the anaerobic...

Embodiment 3

[0041] (1) Preparation of fermentation substrate: Take the primary sludge and residual sludge from the sewage treatment plant and mix them according to the mass ratio of 40%:60% (moisture content is 99.2%, pH=6.8) and put them into a glass container in the laboratory , naturally precipitated at 4°C for 24 hours, and drained the supernatant to obtain a fermentation substrate.

[0042] (2) Pretreatment: Add the fermented substrate and sodium nitrite prepared in step (1) into the anaerobic reactor, and mechanically stir and mix at a temperature of 20±0.1°C at a speed of 120rpm / min for 48 hours , to control the NO in the anaerobic reactor 2 - -N concentration is 600mg NO 2 - -N, pH control is 6.0. pass NO 2 - The concentration of -N, pH and temperature calculate the concentration of free nitrous acid to be 1.54mg HNO 2 -N / L.

[0043] (3) Anaerobic fermentation: Inflate nitrogen into the anaerobic reactor to drive oxygen for 10 minutes, then adjust the pH in the anaerobic r...

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Abstract

The invention discloses a short-chain volatile fatty acid and a preparation method thereof. The preparation method for the short-chain volatile fatty acid comprises the following steps of employing sludge as a fermentation substrate; adding sodium nitrite into the fermentation substrate, performing pretreatment in an acid environment, and performing anaerobic fermentation under an alkaline condition to obtain the short-chain volatile fatty acid. According to the short-chain volatile fatty acid and the preparation method thereof, the sludge of a sewage treatment plant is taken as a raw material, and is jointly treated by virtue of free nitrite pretreatment and alkaline anaerobic fermentation, and the concentration of free nitrite in the system, the pretreatment time, the fermentation pH value and the action of microorganisms in the sludge are controlled to maximally convert undissolved sludge organic matters in the sludge into the short-chain volatile fatty acid, so that the yield of the volatile fatty acid produced from the sludge is further increased on the basis of resourcefully utilizing the sludge and reducing environmental pollution caused by the sludge, and the reaction time is shortened; the short-chain volatile fatty acid and the preparation method thereof have the advantages of high product yield, simple preparation method, energy conservation, consumption reduction, low running cost and the like.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a short-chain volatile fatty acid and a preparation method thereof. Background technique [0002] The simultaneous biological nitrogen and phosphorus removal process of wastewater is an important treatment method to curb water eutrophication. In the process of removing nutrients such as nitrogen and phosphorus, microorganisms in the activated sludge system need to assimilate a large amount of dissolved organic compounds, such as short-chain volatile fatty acids (including acetic acid, propionic acid, butyric acid, etc.). However, in most cases, the content of short-chain volatile fatty acids in wastewater is often insufficient to meet the needs of microbial nitrogen and phosphorus removal in sewage treatment systems, especially in the concentration of organic matter in urban sewage in southern China. In order to avoid additional chemical agents, sludge anaerobic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12P7/54C12P7/52C12P7/40
CPCC12P7/54C12P7/40C12P7/52
Inventor 赵建伟李小明王冬波杨麒陈洪波罗琨邓永超曾光明
Owner HUNAN UNIV
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