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Method for producing biogas by aid of intensified anaerobic fermentation of pretreated circular backflow sludge

A technology of circulating reflux and anaerobic fermentation, applied in the field of solid waste recycling, can solve the problems of anaerobic fermentation process not receiving attention, limiting the technical advantages of anaerobic digestion, long sludge residence time, etc., and shortening anaerobic fermentation. cycle, promoting sludge recycling, and shortening residence time

Active Publication Date: 2012-07-25
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

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

Method used

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  • Method for producing biogas by aid of intensified anaerobic fermentation of pretreated circular backflow sludge
  • Method for producing biogas by aid of intensified anaerobic fermentation of pretreated circular backflow sludge
  • Method for producing biogas by aid of intensified anaerobic fermentation of pretreated circular backflow sludge

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Embodiment 1

[0028] figure 1 A flow chart showing the method for alkaline hydrolysis treatment of circulating reflux sludge intensified anaerobic fermentation to generate biogas according to the present invention.

[0029] 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 input and output are as follows: Take 1L of the above mixed sludge and put it into a 20L effective volume fermenter (the corresponding sludge residence time is 20d), and at the same time discharge 1L into the sludge collection tank. In addition, a circulation outlet is set at the lower end of the fermenter, and 1L (reflux ratio is 5%) of cooked mud is reflowed by gravity to the alkaline hydrolysis regulating device every day, and NaOH is added under the stirring condition of 120rpm, and the dosage of NaOH is 0.05g / gVS. After reacting for 2 hours, add hydro...

Embodiment 2

[0033] 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 input and output are as follows: Take 2L of the above mixed sludge and put it into a 60L effective volume fermenter (corresponding to a sludge residence time of 30d), and at the same time discharge 2L into the sludge collection tank. 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, CaO is added under the stirring condition of 120rpm, and the dosage of CaO is 0.010g / gVS. After reacting for 6 hours, add hydrochloric acid to adjust the pH to 7.5, and then pump it into the fermenter through the sludge circulation pump through the circulation feed port. The gas is collected through the biogas digester every day, and ...

Embodiment 3

[0038] 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 (the corresponding sludge residence time is 25d), and at the same time discharge 800mL into the sludge collection tank. 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. After reacting for 4 hours, add hydrochloric acid to adjust the pH to 7.5, and then pump it into the fermenter through the sludge circulation pump through the circulation feed port. The gas is collected through the biogas digeste...

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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 pretreated circular backflow sludge. 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 pretreated; and collecting the biogas. By the aid of the method, total gas yield by the aid of anaerobic digestion of the sludge is increased, the retention time of the sludge is shortened, and the volume of a sludge anaerobic fermentation tank is reduced.

Description

technical field [0001] The invention belongs to the technical field of solid waste recycling, and relates to a method for pretreating recirculating sludge and strengthening 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 sludge is used for land use, i...

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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