Method for improving methanogenesis of residual sludge by heat and alkali combined pretreatment

A technology for excess sludge and methane production, applied in biological sludge treatment, waste fuel, etc., can solve the problem of low methane production efficiency of excess sludge, achieve sludge reduction, resource pollution of the environment, and increase acid production speed effect

Active Publication Date: 2013-06-26
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention aims to solve the technical problem that the methane production efficiency of excess sludge is not high, and provides a method for improving methane production of excess sludge by combined thermal alkali pretreatment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Add 10 liters of excess sludge to 10 identical 2-liter reactors on average (the reactor is made of plexiglass, with an inner diameter of 100 mm, a height of 260 mm, and a cylindrical shape). It is 15-60min, the initial pH value is adjusted to 8-12, the residence time of sludge in the reactor is 1-12 days, and the temperature is 30-40℃. The optimum conditions for thermal hydrolysis of the sludge were found to be 98-102°C, and the time was 28-32min. The optimum conditions for the acid production stage were the initial pH value of 10.5-11.5, and the residence time in the reactor for 5-7 days. At a temperature of 33-37°C, the obtained short-chain fatty acids were 4361.4 mg per liter (calculated as chemical oxygen demand).

Embodiment 2

[0023] Add 1 liter of excess sludge to a 2-liter reactor, the thermal pretreatment temperature is 98-102 ° C, the time is 28-32 min, the initial pH value of microbial action is 10.5-11.5, and the anaerobic fermentation is 5-7 days. , adjust the pH of the mixture to neutral, add 8% anaerobic granular sludge by volume, control the temperature to be 28-32°C, ferment for 5-7 days, and the methane yield is 0.8 liters.

Embodiment 3

[0025] Add 1 liter of excess sludge to a 2-liter reactor, the thermal pretreatment temperature is 98-102 ° C, the time is 28-32 min, the initial pH value of microbial action is 10.5-11.5, and the anaerobic fermentation is 5-7 days. , adjust the pH of the mixture to neutral, add 10% anaerobic granular sludge by volume, control the temperature to 28-32°C, ferment for 5-7 days, and the methane yield is 1.2 liters.

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Abstract

The invention belongs to the technical field of environmental protection and relates to a method for improving the methanogenesis of residual sludge by heat and alkali combined pretreatment. According to the method, after the residual sludge is thermally pretreated, the dissolving in water of organic matters such as protein and polysaccharide in the residual sludge can be improved significantly so that abundant water-soluble organic matrixes can be provided for the fermentation of the sludge and the generation of acids; and in addition, after the residual sludge is pretreated under the initial alkaline condition, the dissolving and the dehydrating of the sludge can be promoted further and short chain fatty acids can be produced continuously. Therefore, the residual sludge dehydrating efficiency and the acid generating efficiency can be improved greatly by the combination of thermal pretreatment and the initial alkaline condition so that the yield of methane can be increased to the maximum extent.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and relates to a method for improving methane production from excess sludge by combined thermal-alkali pretreatment. Background technique [0002] During the sewage treatment process, about 45-50% of the organic matter in the sewage will be converted into primary sludge and excess sludge. These sludges contain a large amount of pollutants such as organic substances and microorganisms, which can easily cause secondary pollution if they are not treated. In addition, since sludge treatment and disposal costs usually account for more than 60% of the total operating cost of sewage treatment, the rapid growth of urban excess sludge will inevitably lead to increased sewage treatment costs. Therefore, the development of economical and effective treatment and disposal technologies for urban sludge Imperative. The excess sludge contains a large amount of organic substances (such as prote...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/04
CPCY02E50/30
Inventor 张栋高鹏贾舒婷董滨戴晓虎
Owner TONGJI UNIV
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