Method for utilizing enhanced pretreatment to promote anaerobic digestion of excess sludge

A technology of excess sludge and anaerobic digestion, applied in chemical instruments and methods, sludge treatment, biological sludge treatment, etc., can solve the problems of high energy consumption, poor wall breaking effect of excess sludge, and long time.

Inactive Publication Date: 2012-04-25
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the traditional ultrasonic treatment not only consumes a lot of energy,

Method used

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  • Method for utilizing enhanced pretreatment to promote anaerobic digestion of excess sludge

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] After the residual sludge of an urban sewage treatment plant is settled by gravity, the moisture content of the sludge is 97.51%. Sodium hypochlorite solution with an available chlorine content of 3.58% is added to the sludge to make the available chlorine content in the sludge 2.01mg / gTSS, and the sludge is quickly Stir for 30s, then use 20kHz, 1W / mL ultrasonic treatment for 1h, take 500mL combined pretreated sludge sample and anaerobic inoculated sludge at a ratio of 1:1 and send it to the anaerobic digestion reactor. The organic matter load was 159.36mgSCOD / gVSS, and it was placed in a constant temperature room at 35±2°C for mesophilic anaerobic digestion. During the anaerobic digestion process, a magnetic stirrer was used to stir the sludge. After pretreatment, the dissolved chemical oxygen demand in the sludge liquid phase can reach 4358.71mg / L, which is about 27.32 times higher than that of untreated sludge. After 13 days of anaerobic digestion of sludge pretreate...

Embodiment 2

[0021] The properties of the remaining sludge in a sewage treatment plant after gravity settlement are shown in the table below.

[0022]

[0023] Add sodium hypochlorite solution with an available chlorine content of 3.58% to the sludge, so that the available chlorine content in the sludge is 4.02mg / gTSS, stir and mix for 30s, and then use 20kHz, 1W / mL ultrasonic treatment for 1h, take 500mL after joint pretreatment The sludge sample and anaerobic inoculated sludge were sent to the anaerobic digestion reactor at a ratio of 1:1. The initial organic matter load in the anaerobic reactor was 177.88mg / gVSS, and placed in a constant temperature room at 35±2°C for mesophilic anaerobic digestion. Digestion, a magnetic stirrer is used to stir the sludge during anaerobic digestion. After pretreatment, the dissolved chemical oxygen demand in the sludge liquid phase can reach 4408.67mg / L, which is about 27.65 times higher than that of untreated sludge. After 13 days of anaerobic dige...

Embodiment 3

[0025] The residual sludge of an urban sewage treatment plant has a water content of 97.53% through gravity sedimentation, and sodium hypochlorite solution with an effective content of 3.58% is added to the sludge to make the available chlorine content in the sludge 8.04mg / gTSS, and the sludge is stirred rapidly for 10 minutes , followed by 20kHz, 1W / mL ultrasonic treatment for 1h, and 500mL of combined pretreated sludge sample and anaerobic inoculation sludge were sent to the anaerobic digestion reactor at a ratio of 1:1, and the initial organic matter load in the reactor was 152.94 mgSCOD / gVSS, placed in a constant temperature room at 35±2°C for mesophilic anaerobic digestion, using a magnetic stirrer to stir the sludge during anaerobic digestion. After pretreatment, the dissolved chemical oxygen demand in the sludge liquid phase can reach 4738.41mg / L, which is about 29.79 times higher than that of untreated sludge. After 13 days of anaerobic digestion of sludge pretreated b...

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Abstract

The invention relates to a method for utilizing enhanced pretreatment to promote the anaerobic digestion of excess sludge, belonging to the technical field of solid waste treatment. The method comprises the following steps of gravity concentrating excess sludge in urban sewage treatment plants, and then adding certain amount of sodium hypochlorite, stirring the sodium hypochlorite fast with the excess sludge, and then feeding the mixture into an ultrasonic reactor to perform ultrasonic treatment. With the coaction of the ultrasonic and the sodium hypochlorite, the bacterial cell wall structure in the sludge is damaged, the inclusion of the cell is discharged, the content of soluble organic substance in the water is increased, after certain time of treatment, the sludge is fed into an anaerobic digestion reactor to perform subsequent medium temperature anaerobic digestion; the biomass gases generated by the anaerobic digestion are comprehensively utilized through a gas collection device. The concentration of SCOD (soluble chemical oxygen demand) in the sludge liquid phase is improved by about 27 times after the treatment, the biomass gas yield is increased by 54.4%, and the content of methane in the biomass gas is improved by about 10%, so that the energy consumption of the ultrasonic treatment is reduced greatly. With the adoption of the method provided by the invention, for the sewage treatment plants with different sizes, a good effect can be obtained by performing corresponding reconstructions on the existing treatment facilities.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment, and in particular relates to a method for promoting anaerobic digestion of surplus sludge by means of enhanced pretreatment. Background technique [0002] At present, most of the urban sewage treatment plants in our country adopt biological treatment process, but there is a disadvantage of biological treatment, that is, a large amount of excess sludge is produced. Surplus sludge is highly perishable and therefore requires stabilization before it can be utilized or disposed of. Anaerobic digestion is the most commonly used sludge stabilization technology at home and abroad. [0003] The anaerobic digestion process of sludge can be divided into hydrolysis stage, hydrogen and acetic acid production stage and methane production stage. In the hydrolysis stage, poorly soluble organic matter and macromolecular compounds such as lipids, polysaccharides, proteins, and nucleic acids are con...

Claims

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Application Information

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IPC IPC(8): C02F11/00C02F11/04
CPCY02E50/343Y02E50/30
Inventor 刘东方李克勋唐云鹭孟宪荣
Owner NANKAI UNIV
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