Method for producing methane through mixed slaking of straw stalks subjected to alkali treatment and surplus sludge

A technology for excess sludge and straw straws, which is applied in biological sludge treatment, biosynthesis, waste fuel and other directions, can solve the problems of not being properly treated and the low efficiency of separate digestion of straw straws, etc., and achieves improved anaerobic digestion performance. Synergistic effect, the effect of increasing economic benefits

Active Publication Date: 2014-10-15
JIANGNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the end of 2010, the national urban sewage treatment volume reached 34.3 billion cubic meters, and the dewatered sludge production was close to 22 million tons, and 80% of them were not properly treated
Due to the low nitrogen source and mineral content required for bacterial growth in rice straw, the C / N is as high as about 50, so the digestion efficiency of rice straw alone is low; while the C / N of the remaining sludge is as low as 6-16, the rice straw and straw Mixed digestion of excess sludge can regulate anaerobic digestion C / N

Method used

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  • Method for producing methane through mixed slaking of straw stalks subjected to alkali treatment and surplus sludge
  • Method for producing methane through mixed slaking of straw stalks subjected to alkali treatment and surplus sludge
  • Method for producing methane through mixed slaking of straw stalks subjected to alkali treatment and surplus sludge

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Example 1 Changes in cumulative biogas production during mixed digestion of rice straw and excess sludge

[0034] like figure 2 As shown in A, the gas production of group F without adding inoculated sludge was the lowest, and the cumulative gas production was only 54.9mL / gVS, which may be due to the inability of microorganisms in the remaining sludge to degrade rice straw and its own hydrolyzed products. The biogas production of group E was lower, finally 194.1mL / gVS. The biogas yields of group B and group D were 253.9mL / gVS and 283.1mL / gVS, respectively, while the biogas yields of group A and group C after alkali treatment were 319.6mL / gVS and 338.9mL / gVS, respectively, compared with the two groups without alkali treatment An increase of 25.88% and 19.71%, respectively.

[0035] figure 2 B is the change of daily biogas production during anaerobic digestion. It can be seen from the figure that the biogas production lasted until about 22 days, and the gas productio...

Embodiment 2

[0036] Example 2 Changes in cumulative biogas production during mixed digestion of rice straw and excess sludge

[0037] image 3is the average methane volume fraction, methane production and VS removal rate during the reaction. It can be seen from the figure that the average volume fraction of methane in biogas is about 50%, among which, the volume fraction of methane in group B is the lowest at 46.89%, and that in group A after alkali treatment slightly increases to 49.48%. The methane volume fractions of these two groups in alkali treatment group C were 50.06% and 53.69%, respectively, and the methane volume fraction in group E was the highest at 55.68%. This is because the main components of rice straw are carbohydrates such as cellulose, hemicellulose and lignin, and the organic matter in the remaining sludge is mainly protein. The higher the protein content, the higher the methane content in the generated gas. According to the measured biogas production and methane vol...

Embodiment 3

[0042] Example 3 Changes in pH and ammonia nitrogen in the digestion process

[0043] pH changes during digestion Figure 4 As shown in A, it can be seen that the overall pH showed a trend of first decreasing and then increasing. Due to the small amount of methanogenic bacteria in group F, the hydrolyzate could not be further utilized, and the pH dropped rapidly to 5.7. In the subsequent stage, although the hydrolysis of excess sludge produced substances with a buffering effect, the pH rose slightly and remained at about 6.3. Conducive to biogas generation. The pH of groups A and C treated with alkali reached the lowest value on the 2nd day, and then due to the hydrolysis of excess sludge and the subsequent reaction, the pH gradually increased and stabilized at about 7.5, maintaining the optimum value required by methanogens. pH range. In the two groups without alkali treatment, the pH decreased slowly and did not begin to rise until the 10th day. The results showed that al...

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Abstract

The invention discloses a method for producing methane through the mixed slaking of straw stalks subjected to alkali treatment and surplus sludge, and belongs to the technical field of solid waste disposal control and environment-friendly purification treatment. According to the invention, the mixed anaerobic fermentation is adopted to produce methane, the harmless disposal and resource utilization of wastes are realized while the straw stalks and surplus sludge are effectively treated, the system is stable in operation, the energy recovery rate is high, and a better treatment effect is achieved in the situation that the raw material sources are complex.

Description

technical field [0001] The invention relates to a method for producing biogas by mixing and digesting rice straw with alkali and excess sludge, and belongs to the technical fields of solid waste treatment control and environmental protection purification treatment. Background technique [0002] As a large agricultural country, my country has a huge output of rice straw, with an annual output of 230 million tons, which is higher than that of other crop straws. At present, most of them are incinerated or left unused, which wastes resources and is one of the main culprits of smog-like air pollution. The main components of rice straw are cellulose, hemicellulose and lignin carbohydrates, which can produce high value-added substances such as biogas, hydrogen and alcohol under the action of microorganisms. The effective resource utilization of rice straw is of great significance to alleviate the energy and environmental crisis we are facing today. Although hemicellulose and cell...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12P5/02C02F11/04
CPCY02E50/30Y02P20/59
Inventor 阮文权赵明星王永会
Owner JIANGNAN UNIV
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