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Method for increasing yield of short chain fatty acid produced with excess sludge through enzyme and alkali combined pretreatment

A short-chain fatty acid and excess sludge technology, applied in the direction of microorganism-based methods, biochemical equipment and methods, microorganisms, etc., can solve the problems of unstable acid production system and low efficiency of short-chain fatty acid production, and achieve resource reduction , sludge reduction, microbial system stabilization effect

Inactive Publication Date: 2015-08-26
TONGJI UNIV
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The present invention aims to solve the technical problems of low efficiency of short-chain fatty acid production from excess sludge and unstable acid production system, and provides a method that can improve the ratio of high-efficiency fermentation bacteria-Clostridium (strictly anaerobic bacteria) in the anaerobic fermentation process. Method for significantly promoting the production of short-chain fatty acids from excess sludge

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Add 13.2 liters of concentrated residual sludge to 11 identical 2-liter reactors (the material of the reactor is plexiglass, the working volume is 1.5L, the inner diameter is 100mm, the height is 260mm, and it is cylindrical), and the reactor is added Protease K to a concentration of 0-0.04U / g VSS, hydrolyzed at a temperature of 35-37°C and a stirring rate of 120rpm for 2-28h, the best enzyme concentration was measured to be 0.018-0.022U / g VSS, and the time was At 22-26h, the maximum soluble COD obtained was 250.97 mg COD / g VSS. The following examples 2-8 all select better hydrolysis conditions: the concentration of proteinase K is 0.018-0.022U / g VSS, the time is 22-26h, the temperature is 35-37°C, and the stirring rate is 120rpm.

Embodiment 2

[0031] Add 1.2 liters of excess sludge into a 2-liter reactor (the material of the reactor is plexiglass, the working volume is 1.5 L, the inner diameter is 100 mm, the height is 260 mm, and it is cylindrical), and proteinase K is added to the reactor to a concentration of 0.018- 0.022U / g VSS, hydrolyzed for 22-26h at a temperature of 35-37°C and a stirring rate of 120rpm, adding anaerobic granular sludge with a volume percentage of 10%, adjusting the initial pH value to 8.5-9.5, anaerobic fermentation In 1-3 days, the production of short-chain fatty acids was 250.47 mg COD / g VSS, as determined by fluorescence in situ hybridization with 16S rRNA oligonucleotide probes, and the proportion of Clostridium was 28%.

Embodiment 3

[0033] Add 1.2 liters of excess sludge into a 2-liter reactor (the material of the reactor is plexiglass, the working volume is 1.5 L, the inner diameter is 100 mm, the height is 260 mm, and it is cylindrical), and proteinase K is added to the reactor to a concentration of 0.018- 0.022U / g VSS, hydrolyzed for 22-26h at a temperature of 35-37°C and a stirring rate of 120rpm, adding anaerobic granular sludge with a volume percentage of 10%, adjusting the initial pH value to 9.5-10.5, anaerobic fermentation On 1-3 days, the production of short-chain fatty acids was 292.49 mg COD / g VSS, as determined by fluorescence in situ hybridization with 16S rRNA oligonucleotide probes, and the proportion of Clostridium was 32%.

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Abstract

The invention belongs to the technical field of environment protection, and relates to a method for increasing the yield of short chain fatty acid produced with excess sludge through enzyme and alkali combined pretreatment. Precipitated concentrated sludge is obtained after excess sludge stands at 4 DEG Cfor 24 h, proteinase k is added into the concentrated sludge till the concentration of proteinase k ranges from 0.018 U / gVSS to 0.022U / gVSS, the concentrated sludge is hydrolyzed for 22 h to 26 h under 35 DEG Cto 37 DEG Cwith the stirring speed of 120 rpm, then, 10% of anaerobic granular sludge is inoculated, the pH of the sludge is adjusted to range from 9.5 to 10.5, fermentation is carried out for 4 days to 6 days in a reactor under 35 DEG Cto 37 DEG Cat the stirring speed of 120 rpm, short chain fatty acid mixed liquid which mainly contains acetic acid, propionic acid and butyric acid is obtained, and the mixed liquid can serve as a chemical material with high additive value and a methanogenesis matrix. The hydrolysis rate of sludge is increased because the proteinase k is added; the generation of short chain fatty acid is inhibited due to the alkaline condition, but because more than two pretreatment manners are combined, strict anaerobe, particularly clostridium, in acid production microorganisms is enriched, the proportion of facultative microorganisms is reduced, and the acid production rate and the acid production quantity of substrate are increased.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and relates to a method for improving the production of short-chain fatty acids in excess sludge through combined enzyme-alkaline pretreatment. Background technique [0002] As of 2013, there were more than 3,500 sewage treatment plants above the county level in my country, accompanied by a large amount of surplus sludge, and the total sludge production in the country reached 30 million tons (calculated with a moisture content of 80%). It is estimated that by 2020, the sewage Mud output will exceed 60 million tons. Because sludge contains a large amount of organic matter, the energy and resource utilization of sludge has been widely valued by researchers. Due to the social needs of sustainable development and the government's policy support, the focus of solid waste treatment has shifted from pollution control to resource utilization. With the engineering application of anaerobi...

Claims

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Application Information

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IPC IPC(8): C12P7/40C12R1/145
CPCC12P7/54C12P7/40C12P7/52
Inventor 张栋傅翔王涛李晓帅王晓彤戴晓虎
Owner TONGJI UNIV
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