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Method for improving water-removing performance of urban sludge by coupling treatment of ultrasonic wave and chitosan

A technology of municipal sludge and dewatering performance, applied in the direction of dewatering/drying/concentrating sludge treatment, etc., can solve the problems of low removal rate, secondary pollution, leakage, etc., to improve dewatering performance, reduce usage, and reduce costs. Effect

Inactive Publication Date: 2015-09-23
ZUNYI NORMAL COLLEGE
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Problems solved by technology

Moreover, the sludge is composed of flocculent colloids. When an external force is applied, the colloidal fine particles will block and form a filter bridge, which increases the specific resistance value of the sewage in the sludge to be removed by filtration, resulting in mechanical detachment, such as centrifugal detachment. The moisture in the sludge is difficult and the detachment rate is low, which leads to a high moisture content in the sludge, which further makes the sludge bulky and hinders the normal operation of the sewage treatment plant.
[0003] There are many sludge treatment methods in the prior art, among which the chemical conditioning method is more popular. In this process, the sludge is treated with a flocculant, thereby improving the dehydration performance of the sludge. However, In the prior art, the flocculants used are polyacrylamide (PAM) and polyaluminum chloride (PAC), such as a technical scheme for recovering nitrogen and phosphorus and treating sludge dewatering performance in patent No. CN201410064855; however, wherein After the PAM monomer flows into the environment, it may be teratogenic, carcinogenic, and mutagenic, which will bring great harm to the organism and there is a risk of secondary pollution; at the same time, in the process of PAC treatment, due to the sludge treatment method Inappropriate, which will lead to the leakage of aluminum ions into the environment, causing secondary pollution of the environment
[0004] For this reason, some researchers have introduced ultrasonic treatment technology in the process of sludge treatment, which can promote and improve the dewatering performance of sludge, but pure ultrasonic treatment will release a large amount of extracellular polymers, which will increase the sludge centrifugation The COD in the effluent makes the effluent water quality worse; and the effect of pure ultrasound is not significant, and the operating conditions are difficult to control; and, if the ultrasonic density is dense during the ultrasonic treatment process, and the ultrasonic treatment time is longer, the sludge particles will still be changed. , resulting in poor dewatering performance of the sludge
[0005] Therefore, it is necessary for researchers in this field to further treat sludge and improve the dehydration performance of sludge for new technology research, thereby providing protection for sewage treatment plants. At the same time, the technology of ultrasonic combined with chitosan to treat sludge has not yet been seen. have any literature published

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  • Method for improving water-removing performance of urban sludge by coupling treatment of ultrasonic wave and chitosan

Examples

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Embodiment 1

[0025] A method for improving municipal sludge dewatering performance through ultrasonic-chitosan coupling treatment, comprising the following steps:

[0026] (1) The sludge is placed in the adjustment tank, and the pH value of the sludge is adjusted to 4 by adding acid solution therein, then 600 mg of chitosan is added to it according to every liter of sludge, and then the magnetic stirrer is first used at 290r / Min stirred for 0.9min, then adjusted the stirring speed to 47r / min and stirred for 10min;

[0027] (2) Ultrasonic treatment is used to treat the sludge to be used in step 1. The ultrasonic treatment is to immerse the ultrasonic probe in the place 80mm below the sludge liquid surface, and adjust the ultrasonic frequency to 20kHz, and the sound energy density is controlled at 0.3W / mL. Ultrasonic treatment for 1 min, and then put it in a centrifugal dehydrator for centrifugal dehydration treatment, the improvement of sludge dewatering performance can be completed.

[0...

Embodiment 2

[0031] A method for improving municipal sludge dewatering performance through ultrasonic-chitosan coupling treatment, comprising the following steps:

[0032] (1) The sludge is placed in the regulating tank, and the pH value of the sludge is adjusted to 6.5 by adding acid solution therein, then adding 800 mg of chitosan per liter of sludge, and then using a magnetic stirrer at 310r / m Min stirred for 1.2min, then adjusted the stirring speed to 53r / min and stirred for 15min;

[0033] (2) The sludge to be treated in step 1) is treated with ultrasonic treatment. The ultrasonic treatment is to immerse the ultrasonic probe in the place 120mm below the sludge liquid surface, and adjust the ultrasonic frequency to 200kHz, and the sound energy density is controlled at 0.6W / mL. Ultrasonic treatment for 5 minutes, and then put it in a centrifugal dehydrator for centrifugal dehydration treatment, the improvement of sludge dewatering performance can be completed.

[0034] Described acid l...

Embodiment 3

[0037] A method for improving municipal sludge dewatering performance through ultrasonic-chitosan coupling treatment, comprising the following steps:

[0038] (1) The sludge is placed in the regulating tank, and the pH value of the sludge is adjusted to 5.5 by adding acid solution therein, then adding 700 mg of chitosan according to each liter of sludge, and then using a magnetic stirrer at 300r / Min stirring treatment for 1min, then adjust the stirring speed to 50r / min stirring treatment for 13min;

[0039](2) Ultrasonic treatment is used to treat the sludge to be used in step 1. The ultrasonic treatment is to immerse the ultrasonic probe in the place 100mm below the sludge liquid surface, and adjust the ultrasonic frequency to 100kHz, and the sound energy density is controlled at 0.5W / mL. Ultrasonic treatment for 3 minutes, and then put it in a centrifugal dehydrator for centrifugal dehydration treatment, the improvement of sludge dewatering performance can be completed.

...

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Abstract

The invention relates to the technical field of improvement on the water-removing performance of sludge and particularly relates to a method for improving the water-removing performance of urban sludge by coupling treatment of ultrasonic wave and chitosan. The method comprises the following steps: firstly adopting acid liquor to adjust the pH value, adding the chitosan, then stirring for a period of time at high speed, stirring for 10-15 minutes at low speed, then adopting ultrasonic treatment, further enabling bound water, absorbed water, interstitial water and free water in the sludge to be partially removed and further enabling the water content in the sludge to be reduced from more than 98% to less than 68%, and the capillary water absorption time of sludge is reduced. The method has the advantages that the content of polysaccharide and protein in supernatant liquor of sludge treatment is increased, the water-removing performance of the sludge and the quality of the removed water are improved, the operation is simple, the energy consumption is low and the cost is low.

Description

technical field [0001] The invention relates to the technical field of improving sludge dewatering performance, in particular to a method for improving municipal sludge dewatering performance through ultrasonic-chitosan coupling treatment. Background technique [0002] Sludge is a by-product of activated sludge treatment of wastewater in urban sewage treatment plants, and its effective treatment has become one of the key links in the normal operation of urban sewage treatment plants. However, due to the characteristics of high moisture content, large volume and difficult removal of water in sludge, a large amount of sludge is piled up, which hinders the further operation of sewage treatment plants. The moisture contained in sludge exists in four forms, namely interstitial water, free water, surface adsorbed water, and internally bound water. Moreover, the sludge is composed of flocculent colloids. When an external force is applied, the colloidal fine particles will block an...

Claims

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Application Information

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IPC IPC(8): C02F11/12C02F11/14
Inventor 伍远辉罗宿星巫受群卯明飞翟飞范莎莎
Owner ZUNYI NORMAL COLLEGE
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