Three-step two-stage method for producing marsh gas from municipal sludge by anaerobic fermentation

A technology of municipal sludge and anaerobic fermentation, which is applied in the field of solid waste recycling, can solve the problems of difficult biodegradation, removal, and inability to pass biochemical methods, and achieve the goals of increasing degradation rate, reducing sludge volume, and improving biodegradability Effect

Inactive Publication Date: 2012-11-14
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the removal rate of organic matter in the existing anaerobic digestion of sludge is only 40%~50%, and the product of anaerobic digestion of sludge—big residue still has a high content of organic matter, which is mainly inert organic matter that is difficult to biodegrade. Cannot be removed by biochemical methods

Method used

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  • Three-step two-stage method for producing marsh gas from municipal sludge by anaerobic fermentation
  • Three-step two-stage method for producing marsh gas from municipal sludge by anaerobic fermentation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] The properties of municipal sludge in a sewage treatment plant are shown in the table below.

[0015]

[0016] First put the sludge in an anaerobic digestion tank for mesophilic anaerobic digestion under the condition of 35±2°C, and the residence time is 30 days. After that, take the biogas residue from the anaerobic digestion tank and send it to a high-temperature and high-pressure reactor for wet oxidation. Cool to room temperature and send it to an anaerobic digestion tank for mesophilic anaerobic digestion at 35±2°C, with a residence time of 15 days. After three-step two-stage anaerobic fermentation, the sludge VSS removal rate (sludge digestibility) reaches 72.9%-81.3%, which is about 60%-110% higher than the traditional single-step mesophilic anaerobic digestion process, and the sludge volume Reduced by more than 85%, the formed filter cake can be directly landfilled. Example 2:

Embodiment 2

[0017] The properties of municipal sludge in a sewage treatment plant are shown in the table below.

[0018]

[0019] First put the sludge in an anaerobic digestion tank for mesophilic anaerobic digestion at 35±2°C, with a residence time of 20 days. Afterwards, take the biogas residue from the anaerobic digestion tank and send it to a high-temperature and high-pressure reactor for wet oxidation. The biogas residue is cooled to room temperature and sent to an anaerobic digestion tank for mesophilic anaerobic digestion at 35±2°C, with a residence time of 10 days. After three-step and two-stage anaerobic fermentation, the sludge COD removal rate reaches 87.6%-92.3%, and the VSS removal rate (sludge digestibility) reaches 67.4-71.5%. Afterwards, after centrifugal dehydration, the sludge volume is reduced by 95%. The formed filter cake can be directly landfilled.

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Abstract

The invention relates to a three-step two-stage method for producing marsh gas from municipal sludge by anaerobic fermentation, which comprises the following steps: carrying out anaerobic digestion on municipal sludge at 33-37 DEG C or 53-57 DEG C for 15-90 days; putting residual marsh slag in the anaerobic digestion step in a loading reactor to carry out wet oxidation, wherein the temperature is set at 120-320 DEG C according to different sludge properties, an oxidizer is introduced until the gas pressure is 0.5-20 MPa, and the reaction time is 20-90 minutes; cooling the marsh slag subjected to wet oxidation to room temperature, and carrying out anaerobic digestion at 33-37 DEG C or 53-57 DEG C for 15-90 days; and collecting marsh gas generated by digestion by using a gas collection device, and determining the methane content. After the sludge is subjected to anaerobic digestion, the VS (VSS) removal rate is enhanced from 40-50% to 70%, and the COD (chemical oxygen demand) removal rate is up to more than 90%; the dehydration property of the digested sludge is obviously improved; and after dehydration and dewatering, the volume of the sludge can be reduced by more than 85%, and the main components are inorganic substances, thereby efficiently implementing reduction, stabilization and recycling of sludge, and having wide application prospects.

Description

technical field [0001] The invention belongs to the field of solid waste recycling, and in particular relates to a three-step and two-stage anaerobic fermentation method for producing biogas from municipal sludge. Background technique [0002] With the promotion of sewage treatment technology and the continuous development of the economy and society, the sludge production is increasing day by day, which directly leads to the increasingly urgent sludge problem. According to statistics, the surplus sludge production in Chinese cities reaches 2.2×10 7 tons, and is growing at a rate of about 10% per year. The composition of sludge is complex, containing a large amount of organic pollutants, toxic and harmful heavy metals, pathogenic microorganisms, parasite eggs, salts and radionuclides and other refractory substances. If not handled properly, it will cause serious pollution to the environment after discharge. The treatment and disposal of mud has become an urgent problem to be...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/04
CPCY02E50/343Y02E50/30
Inventor 董滨刘晓光戴翎翎戴晓虎
Owner TONGJI UNIV
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