Chemical cleaning method for immersed membrane element

A submerged membrane and element technology, which is applied in the field of chemical cleaning of submerged membrane elements, can solve the problems of poor recovery and achieve a high recovery effect

Inactive Publication Date: 2013-08-14
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, there is a problem of poor recovery

Method used

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  • Chemical cleaning method for immersed membrane element
  • Chemical cleaning method for immersed membrane element
  • Chemical cleaning method for immersed membrane element

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Experimental program
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Embodiment

[0063] The present invention will be specifically described below by referring to Examples and Comparative Examples, but it should be understood that the present invention is not limited to these Examples.

[0064] Waste water from the fiber manufacturing step was used as water to be treated, and after the membrane bioreactor unit was continuously operated for about 3 months, four sets of separation membranes (provided by Toray Industries, Ltd.) in which a decrease in permeation was observed were cleaned in tanks using different cleaning methods. , Inc., submerged membrane for domestic sewage and wastewater, the material is polyvinylidene fluoride, the membrane area is 1.4m 2 ) were cleaned (per group: 1.4m 2 ×5 films). The operating conditions are shown in Table 1. As for the chemical cleaning conditions, four methods shown in Table 2 were performed using sodium hypochlorite (pH 11.7) and sodium hydroxide, and oxalic acid (pH 2.1) and hydrochloric acid. Each chemical was i...

Embodiment 1）

[0081] Chemical cleaning condition 3: 5,000 mg / L of sodium hypochlorite whose pH was adjusted to 12 by adding sodium hydroxide was injected as a first liquid, and contacted for 2 hours. As a result, it was confirmed that pockets were formed in the gap between the film and the support plate. After 2 hours of contact with the first liquid, the residual chemical was suctioned off. 10,000 mg / L of oxalic acid was injected as the second liquid and contacted for 2 hours. As a result, the pockets were dissolved. After 2 hours of contact with the second liquid, the suction filtration operation was restarted.

Embodiment 2）

[0083] Chemical cleaning condition 4: 5,000 mg / L of sodium hypochlorite whose pH was adjusted to 12 by adding sodium hydroxide was injected as a first liquid, and contacted for 2 hours. As a result, it was confirmed that pockets were formed in the gap between the film and the support plate. After 2 hours of contact with the first liquid, the residual chemical was suctioned off. A chemical obtained by adding hydrochloric acid to 10,000 mg / L of oxalic acid to adjust its pH to 1.02 was injected as a second liquid and contacted for 2 hours. As a result, the pockets dissolve. After 2 hours of contact with the second liquid, the suction filtration operation was restarted.

[0084] The research results are shown in Table 2. As a result of the measurement of the respective recovery rates, the recovery rate was as low as 29% in the chemical cleaning condition 1 and as low as 66% in the chemical cleaning condition 2. On the other hand, the recovery rate under chemical cleaning condi...

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Abstract

A chemical cleaning method for an immersed membrane element used in a membrane-separation activated sludge treatment in which organic wastewater containing 1 mg/L or more of manganese is subjected to a biological treatment in an activated sludge treatment vessel followed by solid-liquid separation by a membrane filtration device provided in the treatment vessel, wherein organic decomposition and manganese removal are simultaneously and efficiently carried out and a high recovery effect can be achieved without any adverse effects on microorganisms in activated sludge, when an immersed-membrane element used for a membrane-separation activated sludge treatment of an organic wastewater containing a high concentration of manganese is chemical-washed in an activated sludge treatment vessel by injecting a first solution containing an oxidant from the secondary side into the primary side of the immersed-membrane element, maintaining the same for a given length of time, suctioning and discharging the same from the secondary side of the immersed-membrane element to the outside of the system, injecting a second solution containing an acid from the secondary side to the primary side of the immersed-membrane element, maintaining the same for a given length of time, and carrying out a suction filtration operation.

Description

technical field [0001] The invention relates to a chemical cleaning method for a submerged membrane element arranged in a waste water treatment device. The waste water treatment device has a biological treatment tank and a membrane filtration device. In the biological treatment tank, activated sludge is used to treat Organic wastewater such as domestic sewage or industrial wastewater is treated, and the activated sludge mixture in the biological treatment tank is subjected to solid-liquid separation in the membrane filtration device. Background technique [0002] A membrane bioreactor used in treating domestic sewage or industrial wastewater is a treatment method in which biological treatment is performed in a biological reaction tank, and solid-liquid separation is performed using a filter membrane or the like immersed in the reaction tank. [0003] The membrane bioreactor usually uses air aeration from the lower part of the membrane to clean the surface of the membrane fre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D65/06C02F1/44C02F3/12
CPCB01D65/02B01D2315/06B01D2321/16C02F2303/16B01D2321/162B01D65/06B01D2321/26B01D2321/28C02F3/1273Y02W10/10C02F1/44C02F3/06C02F3/12
Inventor 间谷圣子北中敦木原正浩三好俊郎
Owner TORAY IND INC
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