A method to increase methane gas production in anaerobic digestion of sludge while reducing the ecotoxicity of heavy metals

An anaerobic digestion, heavy metal technology, applied in the fields of sludge detoxification, chemical instruments and methods, sludge treatment, etc., can solve the problem of reducing the adsorption capacity of biochar to heavy metal ions, the poor acid resistance of biochar, and the poor adsorption capacity of heavy metals. and other problems, to achieve the effect of homogenization and the enhancement of the adsorption and complexation capacity of heavy metals, the increase of the specific surface area, and the improvement of the adsorption capacity.

Active Publication Date: 2021-11-02
TONGJI UNIV
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Problems solved by technology

However, due to the continuous high temperature effect of biochar during the pyrolysis process, the number of surface groups is small, and its adsorption capacity for heavy metals is poor.
At the same time, the sludge anaerobic digestion process is a complex system in which microorganisms cooperate with each other. During the acid production stage, the pH value of the digestion system decreases due to the accumulation of volatile fatty acids. The ability of biochar to resist acid is poor, and it will also reduce the adsorption capacity of biochar to heavy metal ions

Method used

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  • A method to increase methane gas production in anaerobic digestion of sludge while reducing the ecotoxicity of heavy metals
  • A method to increase methane gas production in anaerobic digestion of sludge while reducing the ecotoxicity of heavy metals
  • A method to increase methane gas production in anaerobic digestion of sludge while reducing the ecotoxicity of heavy metals

Examples

Experimental program
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Effect test

Embodiment 1

[0031] (1) Preparation of straw biochar BC:

[0032] Corn stalks (taken from a farmer’s market in Shanghai) were placed in a tube furnace. Under anaerobic conditions, the temperature of the tube furnace was raised to 600 °C at a rate of 18 K / min, and then kept at a constant temperature for 180 min. After natural cooling, it was ground and passed through 80 °C. mesh sieve to obtain straw biochar BC;

[0033] (2) Preparation of iron-manganese oxide nanoparticle-loaded biochar material FMBC:

[0034] Under stirring conditions, 5.56g FeSO 4 ·7H 2 O and 0.5g straw biochar BC were added to 70mL deionized water to obtain solution R1, and 1.053g KMnO 4 Add solution R2 to 60mL deionized water; add solution R2 dropwise to solution R1 under constant stirring, and then age at room temperature for 120min. During the reaction, add an appropriate amount of NaOH solution to keep the pH of the reaction system at 9.6. After the reaction is over, centrifuge, wash, and dry to obtain the iron-...

Embodiment 2

[0039] Using the same method as in Example 1, the only difference is that the dosage of FMBC added to the digestion unit in step (3) is 0.151g / g mixed sludge dry matter.

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Abstract

The invention discloses a method for increasing methane gas production in anaerobic digestion of sludge while reducing the ecotoxicity of heavy metals, and belongs to the technical field of environmental protection. The method of the present invention first uses straw as a raw material to produce straw biochar through high-temperature pyrolysis under anaerobic conditions, and the straw biochar is chemically modified under alkaline conditions to obtain a biochar material loaded with iron-manganese oxide nanoparticles, and then the iron Manganese oxide nanoparticle-loaded biochar materials are added to the anaerobic digestion device in a certain proportion for anaerobic fermentation, which can not only greatly enhance the stability of the anaerobic digestion process, increase the methane gas production, but also reduce the ecotoxicity of heavy metals and improve the The adsorption capacity of heavy metal ions.

Description

technical field [0001] The invention relates to a method for increasing methane gas production in anaerobic digestion of sludge while reducing the ecotoxicity of heavy metals, and belongs to the technical field of environmental protection. Background technique [0002] Sewage treatment plants produce a large amount of sludge every year, and the treatment and disposal of sludge has become one of the hot issues in the world. Taking China as an example, 11.2×106 tons of dry sludge is produced every year, and the cost of sludge treatment and disposal accounts for 25%-65% of the total operating cost of the sewage treatment plant. At present, more than 80% of the sludge in our country has not been stabilized, which makes the persistent organic pollutants, pathogens and heavy metals contained in the sludge diffuse in nature, causing harm to the ecological environment and human health. Sludge is rich in organic matter and trace elements, which can be used to increase soil fertility...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F11/04C02F11/00C02F101/20
CPCC02F11/004C02F11/04C02F2101/20Y02E50/30
Inventor 王云才张敏
Owner TONGJI UNIV
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