Method for producing biogas by aid of intensified anaerobic fermentation of circular backflow sludge in microwave and alkali combined treatment

A technology of combined treatment and recirculation, which is applied in the field of solid waste recycling, can solve the problems that the anaerobic digestion process has not received attention, limits the advantages of anaerobic digestion technology, and the sludge has a long residence time, so as to promote the recycling of sludge , shorten the residence time, the effect of convenient application

Active Publication Date: 2012-07-25
TONGJI UNIV
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  • Abstract
  • Description
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  • 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 producing biogas by aid of intensified anaerobic fermentation of circular backflow sludge in microwave and alkali combined treatment
  • Method for producing biogas by aid of intensified anaerobic fermentation of circular backflow sludge in microwave and alkali combined treatment

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Embodiment 1

[0024] figure 1 A flow chart showing the method of the present invention for combined microwave and alkali treatment of circulating sludge to enhance anaerobic fermentation to generate biogas.

[0025] 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 microwave irradiation d...

Embodiment 2

[0030] 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 microwave irradiation device, the microwave frequency is 2450MHz, after 10 minutes of microwave irradiation under the condition of 600W, adjust the pH to 7.5±0.5 by adding hydrochloric acid, and pump it into the fermenter...

Embodiment 3

[0035] 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 input and output are as follows: take 800mL of the above mixed sludge and put it into a 20L effective volume fermenter, and at the same time discharge 1L into the sludge collection tank (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 microwave irradiation device, the microwave frequency is 2450MHz, after 5 minutes of microwave irradiation under the condition of 800W, the pH is adjusted to 7.5±0.5 by adding hydrochloric acid, and the sludge is circul...

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Abstract

The invention belongs to the technical field of solid waste reclamation, and discloses a method for producing biogas by the aid of intensified anaerobic fermentation of circular backflow sludge in microwave and alkali combined treatment. The method includes steps: preparing concentrated sludge and dewatered sludge into mixed sludge; taking the mixed sludge as a fed material for anaerobic digestion; discharging sludge with the same volume; simultaneously repeatedly carrying out anaerobic digestion after the backflow sludge is in microwave and alkali combined treatment; and collecting the biogas. By the aid of the method, recovery ratio of anaerobic fermentation biomass energy of the sludge is increased, gas yield is stabilized, application is convenient, and sludge reclamation of the sludge is further promoted.

Description

technical field [0001] The invention belongs to the technical field of solid waste recycling, and relates to a method for combined microwave and alkali treatment of recirculating sludge to strengthen anaerobic fermentation to generate biogas. 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 slu...

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 严媛媛陈汉龙冯雷雨戴晓虎周琪
Owner TONGJI UNIV
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