Method for pretreating sludge by reflux of fermentation liquor and application of method

A technology of pretreatment and fermentation liquid, applied in sludge treatment, biological sludge treatment, chemical instruments and methods, etc., can solve the problem of high energy consumption, and achieve the effects of increasing gas production, shortening cracking time, and reducing energy consumption

Inactive Publication Date: 2012-07-18
TIANJIN UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the problem of high energy consumption in increasing the hydrolysis acid production rate through ultrasonic pretreatment of sludge alone, and to provide a method of acidifying pretreatment and ultrasonic treatment of sludge to reduce the energy cost of ultrasonic pretreatment and shorten the exhaustion rate. Time required for oxygen digestion, acidification pretreatment combined pretreatment and ultrasonic sludge method to increase gas production

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  • Method for pretreating sludge by reflux of fermentation liquor and application of method

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Effect test

Embodiment 1

[0019] The fermented liquid obtained in the hydrolysis and acidification treatment step is returned to the sludge pretreatment tank through the sludge pump, and the solid content of the sludge in the pretreatment tank is controlled to 2.5%, the reflux ratio of the fermented liquid is 50%, and the mechanical agitation mixes the sewage After the mud and fermentation broth are uniform, acidification pretreatment is carried out, and the pretreatment time is 14 hours. After pretreatment, TCOD in the sludge liquid phase increased by 1340mg / L. The sludge is transported by the sludge pump to a multi-probe ultrasonic processor for ultrasonic cracking, in which the frequency of the ultrasonic reactor is 20kHz, the diameter of the probe is 20mm, and the acoustic energy density is 0.2kW / m 3 , the solid content of the sludge is 2.1%, and the cracking time is 1min. After cracking, the TCOD in the sludge liquid phase increased by 950mg / L. After the ultrasonic treatment, the sludge enters t...

Embodiment 2

[0021] The fermented liquid obtained in the hydrolysis and acidification treatment step is refluxed into the sludge pretreatment tank through the sludge pump, and the solid content of the sludge in the sludge pretreatment tank is controlled to 2.5%, the reflux ratio of the fermented liquid is 55%, and the mechanical stirring After the mixed sludge and fermented liquid are homogeneous, acidification pretreatment is carried out, and the pretreatment time is 24 hours. After pretreatment, TCOD in the sludge liquid phase increased by 1453mg / L. The sludge is transported by the sludge pump to a multi-probe ultrasonic processor for ultrasonic cracking, in which the frequency of the ultrasonic reactor is 20kHz, the diameter of the probe is 20mm, and the acoustic energy density is 0.42kW / m 3 , the solid content of the sludge is 2.1%, and the cracking time is 3 minutes. After cracking, TCOD in the sludge liquid phase increased by 1023mg / L. After the ultrasonic treatment, the sludge ent...

Embodiment 3

[0023] The fermented liquid obtained in the hydrolysis and acidification treatment step is refluxed into the sludge pretreatment tank through the sludge pump, and the solid content of the sludge in the sludge pretreatment tank is controlled to 2.9%, the reflux ratio of the fermented liquid is 67%, and the mechanical stirring After the mixed sludge and fermentation broth are evenly mixed, acidification pretreatment is carried out, and the pretreatment time is 36 hours. After pretreatment, TCOD in the sludge liquid phase increased by 2142mg / L. The sludge is transported by the sludge pump to a multi-probe ultrasonic processor for ultrasonic cracking. The frequency of the ultrasonic reactor is 28kHz, the diameter of the probe is 25mm, and the sound energy density is 0.65kW / m 3 , the solid content of the sludge is 2.4%, and the cracking time is 5 minutes. After cracking, TCOD in the sludge liquid phase increased by 1987mg / L. The ultrasonically treated sludge enters the hydrolysis...

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Abstract

The invention discloses a method for pretreating sludge by the reflux of fermentation liquor. The method comprises the following steps of: pretreating the sludge by using an ultrasonic wave in an ultrasonic treater, and hydrolyzing and acidizing the sludge in a hydrolytic acidification tank; and performing methane fermentation on the hydrolyzed and acidized sludge in a methanogenesis tank, wherein the fermentation liquor obtained by hydrolysis and acidification flows back to a sludge pretreatment tank and is mixed with sludge which is not subjected to ultrasonic pretreatment to perform acidizing pretreatment, and the mixture is subjected to subsequent ultrasonic pretreatment. According to the method, the acidizing pretreatment and the ultrasonic treatment are combined, so that the gas production rate can be improved effectively, the retention time of the sludge can be reduced, and the volume of a digestion tank can be reduced; and the density of required ultrasonic acoustic energy is reduced substantially, and energy consumption is reduced effectively, so that a pretreatment process can be applied to methane production practically.

Description

technical field [0001] The invention belongs to the field of wastewater biological treatment, and mainly relates to a new method for ultrasonically disintegrating pretreated sludge by ultrasonic sludge, and returning acid hydrolyzate in the hydrolysis and acidification stage to the pretreated sludge. After the process is implemented, the gas production of anaerobic digestion can be increased, the time required for the anaerobic methane production stage can be reduced, and the cost of fermentation broth pretreatment can be reduced. Background technique [0002] Sewage plant sludge needs to be stabilized before landfilling. Anaerobic digestion is an effective method, and anaerobic digestion has attracted more and more attention because of its ability to generate energy. The anaerobic digestion of sludge can be divided into three stages: hydrolysis fermentation, acidification fermentation and methane fermentation. The latter two stages proceed very quickly, while the hydrolysis...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/00C02F11/04
CPCY02E50/343Y02E50/30
Inventor 王芬季民王拓
Owner TIANJIN UNIV
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