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Method for generating methane by enhancing anaerobic digestion of reflux sludge after heat and alkaoline combined treatment and circulation

A technology of anaerobic digestion and combined treatment, applied in the field of solid waste recycling, can solve the problems of anaerobic digestion process not receiving attention, limiting the technical advantages of anaerobic digestion, poor sludge degradation, etc., and shortening anaerobic digestion. cycle, promote sludge recycling, and enhance the effect of mixing

Inactive Publication Date: 2012-07-18
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Traditional anaerobic digestion has the disadvantages of slow reaction, long sludge residence time (30-40 days), large tank volume, low methane production and poor sludge degradation degree, which limit the advantages of anaerobic digestion technology.
In recent years, domestic and foreign scholars have mostly considered how to strengthen the pretreatment method in the research on improving the recovery of biomass by anaerobic digestion of sludge, but the improvement of anaerobic digestion process has not received much attention.

Method used

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  • Method for generating methane by enhancing anaerobic digestion of reflux sludge after heat and alkaoline combined treatment and circulation
  • Method for generating methane by enhancing anaerobic digestion of reflux sludge after heat and alkaoline combined treatment and circulation

Examples

Experimental program
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Effect test

Embodiment 1

[0025] figure 1 A flow chart showing the method of the present invention for the combined treatment of circulating sludge with heat and alkali for enhanced anaerobic digestion and gas production.

[0026] Take the concentrated sludge and dewatered sludge from a sewage treatment plant in a certain place and prepare mixed sludge with a water content of 92% and a VS / TS of 0.45 in a sludge blending tank. The daily normal feeding and discharging are as follows: Take 1L of the above mixed sludge and put it into a 20L effective volume fermenter, and discharge 1L into the sludge collection tank at the same time (the corresponding residence time is 20d). In addition, a circulation outlet is set at the lower end of the fermenter, and 1L of cooked mud (reflux ratio is 5%) is reflowed to the alkali hydrolysis regulating device by gravity every day, and NaOH is added under the stirring condition of 120rpm, and the dosage of NaOH is 0.05g / gVS, and then put it into the heating pretreatment...

Embodiment 2

[0031] Take the concentrated sludge and dewatered sludge from a sewage treatment plant in a certain place and prepare mixed sludge with a water content of 98% and a VS / TS of 0.75 in a sludge blending tank. The daily normal feeding and discharging are as follows: Take 2L of the above mixed sludge and put it into a 60L effective volume fermenter, and discharge 2L into the sludge collection tank at the same time (the corresponding residence time is 30d). In addition, a circulation outlet is set at the lower end of the fermenter, and 4L cooked mud (reflux ratio is 6.7%) is reflowed to the alkaline hydrolysis regulating device by gravity every day, and CaO is added under the stirring condition of 120rpm, and the dosage of CaO is 0.10g / gVS, and then put it into the heating pretreatment device and heat it at 100 degrees for 30 minutes, then adjust the pH to 7.5±0.5 by adding hydrochloric acid, and pump it into the fermentation tank through the sludge circulation pump. The gas is col...

Embodiment 3

[0036] Take the concentrated sludge and dewatered sludge from a sewage treatment plant in a certain place and prepare mixed sludge with a moisture content of 88% and a VS / TS of 0.33 in a sludge blending tank. The daily normal feeding and discharging are as follows: Take 800mL of the above mixed sludge and put it into a 20L effective volume fermenter, and discharge 1L into the sludge collection tank at the same time (the corresponding residence time is 25d). In addition, a circulation outlet is set at the lower end of the fermenter, and 2L of cooked mud (reflux ratio is 10%) is reflowed to the alkaline hydrolysis regulating device by gravity every day, and Ca(OH) is added under the stirring condition of 120rpm 2 , Ca(OH) 2 The dosage is 0.15g / gVS, and then put into the heating pretreatment device and heated at 90°C for 60min, then adjust the pH to 7.5±0.5 by adding hydrochloric acid, and pump it into the fermentation tank through the sludge circulation pump. The gas is collect...

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Abstract

The invention belongs to the technical field of recycling of solid wastes and discloses a method for generating methane by enhancing anaerobic digestion of reflux sludge after heat and alkaoline combined treatment and circulation. The method comprises the following steps: preparing mixed sludge from concentrated sludge and dehydrated sludge; feeding the mixed sludge and performing anaerobic digestion; discharging the sludge with the same volume; performing heat and alkaoline combined pretreatment on the reflux sludge; circulating and performing anaerobic digestion; and collecting the methane. In the method, a heat and alkaoline combined pretreatment circulation reflux sludge system is provided, so the mixed effect of a fermentation system is enhanced, dissolution of solid organic matters is enhanced, and the reactor can operate efficiently and stably.

Description

technical field [0001] The invention belongs to the technical field of solid waste recycling, and relates to a method for generating biogas by thermal-alkali joint treatment of circulating sludge and enhanced anaerobic digestion. Background technique [0002] my country has built a large number of sewage treatment plants. As of 2009, 1,792 urban sewage treatment plants have been built nationwide, with a treatment capacity of 99.04 million m 3 / d, the average operating load rate is 81.27%. While the construction and operation of these sewage treatment plants have played an important role in the reduction of urban pollution load, the amount of urban sludge, a by-product of the sewage treatment process, is also increasing day by day. At present, the annual production of wet sludge in the country is nearly 30 million tons (water content 80%), and the center of sludge treatment and disposal has shifted from simple landfill to resource-based land use. Before the sludge is used f...

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 严媛媛陈汉龙冯雷雨戴晓虎周琪
Owner TONGJI UNIV
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