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A Method for Removing Heavy Metals from Surplus Activated Sludge

A residual activity, sludge technology, applied in biological sludge treatment, chemical instruments and methods, water/sludge/sewage treatment, etc., can solve the problems of low metal dissolution, high chemical method cost, difficult operation, etc. The effect of high metal dissolution rate, low treatment cost and low acid consumption

Inactive Publication Date: 2011-12-28
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the chemical method has the disadvantages of high cost, difficult operation, high energy consumption and low metal dissolution.
Therefore, the removal of heavy metals from remaining activated sludge is limited

Method used

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  • A Method for Removing Heavy Metals from Surplus Activated Sludge
  • A Method for Removing Heavy Metals from Surplus Activated Sludge
  • A Method for Removing Heavy Metals from Surplus Activated Sludge

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] 1. Determination of heavy metal content in sludge before treatment

[0045] The remaining activated sludge from the sewage treatment plant is centrifuged to obtain the precipitated part, and after drying at 105 ° C, 1.0 g is digested with a mixed acid solution of concentrated nitric acid and perchloric acid, using 1% HNO 3 Clean the flask, elute the precipitate completely, filter it with filter paper, adjust the volume of the filtrate to 25mL, then filter it with a 0.45μm filter membrane, take 10mL of the filtrate, and use the ICP method to detect the heavy metal content.

[0046] 2. Preparation of Thiobacillus ferrooxidans T.f

[0047] Preparation of medium, prepare the liquid part: (NH 4 ) 2 SO 4 0.6g, KCl 0.02g, K 2 HPO 4 0.1g, MgSO 4 ·7H 2 O 0.1g, Ca(NO 3 ) 2 4H 2 O 0.002g, distilled water 200mL, with H 2 SO 4 Adjust the pH to 2.0, sterilize with high pressure steam at 121°C for 20min; prepare the solid part: FeSO 4 .7H 2 O 8.8g, sterilized by ultravi...

Embodiment 2

[0059] 1. the mensuration of sludge heavy metal content before treatment is the same as embodiment 1

[0060] 2. The preparation of Thiobacillus ferrooxidans is the same as in Example 1

[0061] 3. The preparation of Thiobacillus thiooxidans is the same as in Example 1

[0062] 4. Heavy metal removal --- biological leaching operation

[0063] Prepare the triangular flask and the liquid composition in the same example 1, add 20.0g dewatered sludge in the bottle, 4mL T.f bacterial liquid and 4mL T.t bacterial liquid, 8.8g FeSO 4 and 2g S.

[0064] The initial pH of the leachate is H 2 SO 4 Adjust to 5.0. The bioleaching reaction was carried out in a shaking incubator at a temperature of 28° C., and the rotation speed was adjusted at 150 rpm. The leaching reaction was stopped after 12 days.

[0065] 5. the mensuration of sludge heavy metal content after treatment is the same as embodiment 1

[0066] 6. Experimental results

[0067] Heavy metal removal rate before and aft...

Embodiment 3

[0071] 1. the mensuration of sludge heavy metal content before treatment is the same as embodiment 1

[0072] 2. The preparation of Thiobacillus ferrooxidans is the same as in Example 1

[0073] 3. The preparation of Thiobacillus thiooxidans is the same as in Example 1

[0074] 4. Heavy metal removal --- biological leaching operation

[0075] Prepare the triangular flask and the inner liquid composition with example 1, add 40.0g dewatered sludge in the bottle, 8mL T.f bacterium liquid and 8mL T.t bacterium liquid, 8.8g FeSO 4 and 2g S.

[0076] The initial pH of the leachate is H 2 SO 4 Adjust to 7.0. The bioleaching reaction was carried out in a shaking incubator at a temperature of 35° C., and the rotation speed was adjusted at 150 rpm. The leaching reaction was stopped after 6 days.

[0077] 5. the mensuration of sludge heavy metal content after treatment is the same as embodiment 1

[0078] 6. Experimental results

[0079] Heavy metal removal rate before and after...

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Abstract

The invention discloses a method for removing heavy metals in residual activated sludge. Indigenous Thiobacillus ferrooxidans (Thiobacillus ferrooxidans,T.f) and Thiobacillus thiooxidans (Thiobacillus thiooxidans, T.t) are adopted, inoculated in a system containing the residual activated sludge respectively, undergo leaching reaction, and are subjected to shaking culture at temperature of between 28 and 35 DEG C; initial pH value is between 4 and 7; and leaching time is between 6 and 12 days. The leaching of an indigenous T.f and T.t mixed strain cluster has high removing rate for the heavy metals in the residual activated sludge, and is superior to the leaching effect of a T.f single strain and a T.t single strain. The indigenous T.f and T.t mixed strain cluster has the following removing rate for the heavy metals in the residual activated sludge respectively: Cu 98.32 percent, Zn 98.60 percent, Cr 93.47 percent, Ni 97.88 percent and As 96.09 percent. The process flow has the advantages of little acid consumption, low energy consumption, low treatment cost, high metal dissolution rate, mild treatment condition, normal temperature and normal pressure reaction, and simple operation, and has good application prospect.

Description

technical field [0001] The invention relates to a method for removing heavy metals in excess activated sludge by using indigenous Thiobacillus ferrooxidans and Thiobacillus thiooxidans, which is used in the technical field of removing heavy metals from excess activated sludge in sewage treatment plants. Background technique [0002] 70% of sewage treatment plants in my country use biological methods to treat sewage. The activated sludge process is one of the most commonly used biological processes. The microorganisms in the activated sludge also grow and multiply while purifying the sewage, and increase continuously, which makes the concentration of activated sludge in the sewage treatment tank too high, resulting in the lack of oxygen in the sewage and affecting the effect of sewage treatment. Therefore, a certain amount of sludge must be discharged regularly to keep the concentration of activated sludge in the sewage treatment tank at a certain level, and this part of the...

Claims

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Application Information

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IPC IPC(8): C02F3/12C02F11/02
CPCY02W10/10
Inventor 宋存江王聪王淑芳陈娟孙村民郭文斌邓飞
Owner NANKAI UNIV
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