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Method for improving dewaterability of activated sludge through addition of microbial flocculant

A microbial flocculant and activated sludge technology, which is applied in the direction of dehydration/drying/thickened sludge treatment, can solve the problems of poor dehydration performance and high cost of mud cake subsequent treatment and disposal, and achieves easy operation, low investment and operation cost, and source wide range of effects

Active Publication Date: 2013-12-11
BEIJING NORMAL UNIVERSITY
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] The patent of the invention aims at the status quo of poor dehydration performance of residual sludge in urban and industrial sewage treatment plants and high cost of subsequent treatment and disposal of mud cakes, overcomes the environmental risks caused by the application of traditional inorganic and organic polymer flocculants, and provides a dosing The method of microbial flocculant conditioning sludge to improve the dehydration performance of excess activated sludge, while avoiding secondary pollution and other problems, achieve the purpose of sludge reduction and resource disposal

Method used

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  • Method for improving dewaterability of activated sludge through addition of microbial flocculant
  • Method for improving dewaterability of activated sludge through addition of microbial flocculant
  • Method for improving dewaterability of activated sludge through addition of microbial flocculant

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Embodiment 1

[0044] The fermented liquid after shaking culture was centrifuged at 5000r / min for 30min, and the supernatant was the liquid microbial flocculant, and the flocculant produced by Klebsiella isolated and screened was used to treat the 4g / L kaolin suspension solution. 0.4g of kaolin, 5mL of CaCl passed through a 60 mesh sieve 2 (1%) solution and 2mL fermentation supernatant were mixed in a 250mL beaker, added deionized water to 100mL, magnetic stirrer 400r / min fast stirring 1min, 150r / min slow stirring 5min, transferred to a 100mL graduated cylinder and left standing for 5min. Measure the absorbance (A) of the supernatant under the 550nm wavelength of the ultraviolet spectrophotometer, choose fresh medium to replace the fermentation broth, and measure the absorbance of the kaolin suspension after processing as a contrast (A 0 ) The calculation formula of flocculation rate (Fr) is as follows:

[0045] Fr = A ...

Embodiment 2

[0049] Application of Klebsiella flocculants to conditioned sludge to improve sludge dewaterability. 25mL of the sludge sample to be tested was added with 0-5mL of microbial flocculant, stirred rapidly at 400r / min for 60s on a magnetic stirrer, and slowly stirred at 150r / min for 5min, and moved to the sludge specific resistance measuring device (attached image 3 ), filter under the condition of constant vacuum 0.05MPa, record the filtration time t and the corresponding filtrate volume V. Sludge specific resistivity (SRF) and water content were selected to characterize the sludge dewatering effect, and the water content was determined by gravimetric method. Sludge specific resistance (Specific resistance in filtration, SRF) refers to the resistance of unit mass sludge on unit filtration area when filtering under constant pressure. The larger the sludge specific resistance, the worse the filtration performance. The calculation of sludge specific resistance is shown in the formu...

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Abstract

The invention discloses a method for improving dewaterability of activated sludge through addition of a microbial flocculant. According to the method, Klebsiella pneumoniae capable of generating the microbial flocculant is separated, purified and screened from activated sludge in a sewage treatment plant, then shake fermentation cultivation is carried out at a temperature of 25 to 40 DEG C at a rotating speed of 100 to 200 r / min for 2 to 3 d, and a flocculant sample is extracted from fermentation supernatant through frozen ethanol precipitation; and the microbial flocculant is added into an activated sludge sample, specific resistance of filtration (SRF) and water content of the regulated sludge are respectively reduced to 4.66*10<12> m / kg and 83.74%, and compared to chemical flocculants like aluminum sulfate and poly aluminum chloride (PAC), the microbial flocculant enables a better dewatering effect to be obtained. The microbial flocculant has good adaptability to characteristics like sludge salt waste and a pH value, and the regulated activated sludge has substantially improved dewaterability and the advantages of easy biodegradability, high efficiency, no toxicity, etc.

Description

technical field [0001] The invention relates to a method for improving the dewatering performance of activated sludge by adding microbial flocculants, focusing on the separation, purification and screening of a floc-producing bacteria, and its application in activated sludge dewatering, belonging to environmental engineering and sludge Dealing with technical fields. Background technique [0002] Activated sludge is a by-product of municipal sewage treatment. With the expansion of urban and industrial sewage treatment scale, the output of residual sludge is increasing year by year. In 2010, my country's sewage plants produced about 21.7 million tons of sludge (calculated with a moisture content of 80%). The harmless disposal of a large amount of sludge has increasingly become a major problem in the field of environmental protection. The excess sludge has high moisture content, poor dehydration performance, and contains a large amount of refractory organic matter, heavy metal...

Claims

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Application Information

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IPC IPC(8): C02F11/14
Inventor 马俊伟刘杰伟刘彦忠杨娅王洪涛岳东北
Owner BEIJING NORMAL UNIVERSITY
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