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ph controlling technology for converting municipal sludge into acetic acid

A municipal sludge and acetic acid technology, applied in the field of waste recycling, can solve the problems of insufficient SCOD degradation capacity, increased wastewater treatment costs, and high SCOD index, and achieve the effects of reducing SCOD index, low cost, and high economic value

Inactive Publication Date: 2010-05-05
JIANGNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Qiu Jian et al. found that the pH has a greater impact on the reactor, and the pH was controlled at 9-10. Although the acetic acid content increased (Qiu Jian, Regulating pH to promote sludge acid production efficiency and two-phase coupling system directional acetic acid production, China Water Supply and Drainage, 2009.25(13)), but the SCOD degradation ability is insufficient, and the SCOD index in the wastewater discharged from the reactor is very high, which leads to an increase in the cost of wastewater treatment in the later stage

Method used

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  • ph controlling technology for converting municipal sludge into acetic acid
  • ph controlling technology for converting municipal sludge into acetic acid
  • ph controlling technology for converting municipal sludge into acetic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Method 1: Coupled system without process pH control

[0021] The initial SCOD value of waste municipal sludge in phase A is 16000mg / L.

[0022] Hydrogen-producing acetic acid phase (phase A): Seed sludge with a concentration of 4gVS / L (VS refers to volatile solids), sludge pretreatment liquid, the initial pH is adjusted to 10, and the pH is not controlled during the fermentation process.

[0023] Hydrogen consuming and acetogenic phase (H phase): seed sludge, concentration 6gVS / L, initial pH 6.5, pH is not controlled during the fermentation process.

[0024] Fermentation conditions: fill with nitrogen for 10-40 minutes, seal, ferment at 30-40°C, mix the seed mud and substrate by magnetic stirring or other methods.

[0025] Method 2: Coupled system to control process pH

[0026]The initial SCOD value of waste municipal sludge in phase A is 16000mg / L.

[0027] Hydrogen and acetic acid production phase (phase A): Seed sludge, concentration 4gVS / L, sludge pretreatment li...

Embodiment 2

[0033] Embodiment 2: Adopt the coupling system of pH control technology (A phase initial pH9.0)

[0034] The initial SCOD value of waste municipal sludge in phase A is 16000mg / L.

[0035] Hydrogen and acetic acid production phase (Phase A): seed sludge, concentration 4gVS / L, sludge pretreatment liquid, initial pH is adjusted to 9, and pH is adjusted to 9 once a day starting from 13 days of fermentation.

[0036] Hydrogen consuming and acetogenic phase (H phase): Seed slime with a concentration of 6gVS / L and an initial pH of 6.5. During the fermentation process, the pH was adjusted once a day to keep the pH at 6.5.

[0037] Fermentation conditions: fill with nitrogen for 10-40 minutes, seal, ferment at 30-40°C, mix the seed mud and substrate by magnetic stirring or other methods.

[0038] Table 1 Coupling system using pH control process (phase A initial pH9.0)

[0039] time (d)

Embodiment 3

[0040] Embodiment 3: Adopt the coupling system of pH control technology (A phase initial pH10.0)

[0041] The initial SCOD value of waste municipal sludge in phase A is 16000mg / L.

[0042] Hydrogen and acetic acid production phase (phase A): the concentration of the seed sludge is 4gVS / L, the initial pH is adjusted to 10, and the pH is adjusted once a day from the 13th day of fermentation, and the pH is adjusted to 10.

[0043] Hydrogen consuming and acetogenic phase (H phase): the seed sludge concentration is 6gVS / L, the initial pH is 6.5, and the pH is adjusted once a day during the fermentation process to keep the pH value at 6.5.

[0044] Fermentation conditions: fill with nitrogen for 10-40 minutes, seal, ferment at 30-40°C, mix the seed mud and substrate by magnetic stirring or other methods.

[0045] Table 2 Coupling system adopting pH control process (initial pH of phase A is 10.0)

[0046] time (d)

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Abstract

The invention provides a pH controlling technology for converting municipal sludge into acetic acid, belonging to the field of the recovery of waste. The technology performs different pH control modes to two phases in a coupling system of generating hydrogen and generating acid / consuming hydrogen and generating acetic acid. Before 12 days of fermenting generating hydrogen and generating acid phase (A phase), the pH is not controlled, and from 13 days, the pH is remained at 9-10; the pH is remained at 6.5 when fermenting consuming hydrogen and generating acetic acid (H phase); and the fermentation is stopped after 18 days. The concentration of A phase acetic acid is 7.53g / L, the concentration of H phase acetic acid is 1.45g / L, and the index of A phase SCOD is reduced by 56.7%. The technology solves the problem of the environment pollution caused by the municipal sludge, obtains the acetic acid with high additional value, discharges the polluted water which is easily processed (SCOD index is low), and has the advantages of convenient operation, low cost and obvious effect, etc.

Description

technical field [0001] A pH control process for converting municipal sludge into acetic acid belongs to the field of waste resource utilization. Background technique [0002] With the acceleration of urbanization in my country, the rate of urban sewage treatment has increased year by year, and the amount of sludge produced by urban sewage plants has also increased sharply. At present, there are more than 1,320 urban sewage plants that have been built and operated in my country, with an annual treatment capacity of 97.25 million m3. According to estimates, the amount of sludge (dry weight) discharged by my country's urban sewage treatment plants is about 5.32 million tons, and the wet weight is 26.62 million tons (water content 80%), and the annual growth rate is more than 15%. Therefore, it is imminent to develop a cost-effective treatment and disposal technology for municipal sludge. At present, my country's sludge recycling and harmless treatment technologies include agr...

Claims

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Application Information

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IPC IPC(8): C12P7/54
Inventor 刘和扶郡石峰李秀芬
Owner JIANGNAN UNIV
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