Method for extracting bioflocculant from excess activated sludge

A biological flocculant and excess sludge technology, applied in sludge treatment, chemical instruments and methods, water/sludge/sewage treatment, etc., to achieve the effect of low preparation cost, simple operation process, and good promotion and use value

Inactive Publication Date: 2011-08-17
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, so far, there have been no reports of extracting bioflocculants from excess sludge at home and abroad.

Method used

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  • Method for extracting bioflocculant from excess activated sludge
  • Method for extracting bioflocculant from excess activated sludge
  • Method for extracting bioflocculant from excess activated sludge

Examples

Experimental program
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Effect test

Embodiment 1

[0022] A. The remaining sludge is concentrated to obtain gravity thickened sludge. Adopt A from 2 The sewage treatment plant of the / O treatment process takes back the return sludge of the secondary sedimentation tank as the remaining sludge, puts it in a refrigerator at 4°C within half an hour, and dumps the supernatant after 14 hours, and the gravity obtained after the supernatant is dumped Mix the concentrated sludge evenly. At this time, the gravity concentrated sludge concentration should reach 18.0-20.0g / L, VSS / SS=68.0%-75.0%, and the pH value is 6.5-7.0;

[0023] B. Ultrasonic treatment of gravity thickened sludge to obtain sludge samples. Take out the gravity concentrated sludge obtained in step A from the refrigerator, mix it and put it in a 100ml plastic jar, about 90ml; use a 20KHz ultrasonic cell breaker from Shanghai Shengxi Ultrasonic Instrument Co., Ltd., at a power of 120W Next, select continuous ultrasound mode, 13mm probe, and continue ultrasound for 30s; ...

Embodiment 2

[0027] A. The remaining sludge is concentrated to obtain gravity thickened sludge. Retrieve the return sludge from the secondary settling tank from a sewage treatment plant that adopts a double sludge treatment system process, place it in a refrigerator at 5°C within half an hour, pour off the supernatant after 12 hours, and dump the supernatant Concentrate the sludge by gravity and mix evenly. At this time, the concentration of the sludge by gravity concentration should reach 15.0-16.0g / L, VSS / SS=65.0%-70.0%, and the pH value is 7.0-7.5.

[0028] B. Ultrasonic treatment of gravity thickened sludge to obtain sludge samples. Take out the gravity concentrated sludge obtained in step A from the refrigerator, mix it and put it in a 100ml plastic jar, about 90ml; use a 20KHz ultrasonic cell breaker from Shanghai Shengxi Ultrasonic Instrument Co., Ltd., at a power of 180W Next, choose 1-8 seconds pulsed ultrasound for continuous ultrasound mode, 13mm probe, continuous ultrasound for ...

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Abstract

The invention relates to a method for extracting bioflocculant from excess activated sludge, in particular to a method for preparing the bioflocculant by adopting an ultrasonic method. The method comprises the following steps of: A, getting back the excess activated sludge from a sewage treatment plant adopting a biological treatment process, standing for 8-24h at a temperature of 4-5 DEG C, and dumping supernate to obtain gravity concentrated sludge; B, carrying out ultrasonic treatment on the gravity concentrated sludge for 30-120s under the conditions that the frequency is 20-53kHz and the power is 120-240W to obtain a sludge sample; and C, centrifuging the sludge sample for 10-30min at a speed of 6,000-12,000rpm to obtain supernate, namely the bioflocculant. Determination on the bioflocculant provided by the invention shows that flocculation can be about 70% when pH value is equal to 9.0, and the flocculation effect is rapidly promoted while the alkalinity is increased; the bioflocculant is biodegradable, and no secondary pollution is produced after the bioflocculant is used; the price is low, the process controllability is high, the requirement of industrial production can be easily met, good environmental, economic and social benefits are realized, and the bioflocculant can be widely applicable to recycling of the excess activated sludge produced by a sewage biological treatment plant.

Description

technical field [0001] The invention relates to a preparation method of a biological flocculant, in particular to a method for extracting the biological flocculant from excess sludge by means of an ultrasonic method. Background technique [0002] Flocculants are substances that can coagulate and precipitate suspended particles that are not easy to settle in liquids. They are widely used in industrial water treatment, domestic sewage treatment, food production and fermentation industries. Flocculants can generally be divided into three categories: ①Inorganic flocculants, such as aluminum sulfate, polyaluminum chloride, ferrous sulfate and alum; ②Synthetic organic polymer flocculants, such as polyethylene oxide, polystyrene sulfonate , polyacrylamide derivatives and polyethyleneimine, etc.; ③ natural organic polymer flocculants, such as cellulose, starch, polyglucosamine, sodium alginate and biological flocculants. Many inorganic flocculants are widely used due to their good ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/56C02F11/00C02F11/12
Inventor 张志强张艳君李向蓉戴晓晴王春晖
Owner TONGJI UNIV
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