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Cleaning method of immersed ultrafiltration membrane

An ultrafiltration membrane and submerged technology, which is applied in the cleaning field of submerged ultrafiltration membranes, can solve the problems of decreased permeate flux, increased transmembrane pressure difference, and difficulty in cleaning, etc., to reduce operating pressure and reduce transmembrane The effect of pressure difference and restoration of permeate flux

Inactive Publication Date: 2020-06-02
LUTAI TEXTILE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the fouling components on the membrane surface are complex and multiple pollutants (including carbonate scale, sulfate scale, colloid, organic matter, microorganisms, iron, manganese, etc.) coexist, it is difficult to clean thoroughly with only one or two cleaning agents
When a certain pollutant cannot be completely cleaned, it will quickly cause membrane fouling, resulting in a decrease in permeate flux and a rapid increase in transmembrane pressure difference

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Embodiment one: the concrete cleaning step to submerged ultrafiltration membrane is:

[0023] 1) The first alkaline cleaning: empty the ultrafiltration membrane pool, transport the alkaline cleaning solution into the ultrafiltration membrane pool, until the cleaning solution completely submerges the ultrafiltration membrane wire, soak the ultrafiltration membrane for 8 hours, soak During the process, use compressed air or Roots blower to aerate and stir the soaking liquid and ultrafiltration membrane filaments in the ultrafiltration membrane pool, and aerate for 1min every 1h. Alkaline cleaning solution is prepared with reverse osmosis water or low hardness tap water, the temperature is 25°C, the composition is sodium hydroxide and sodium hypochlorite, the mass fraction of sodium hydroxide is 2%, the concentration of sodium hypochlorite is 4000ppm in terms of available chlorine, and the rest is reverse osmosis Produced water or tap water with low hardness;

[0024] 2) ...

Embodiment 2

[0031] Embodiment 2: The specific operation steps are the same as in Embodiment 1, and the citric acid in step 3 is replaced with oxalic acid prepared with a mass concentration of 2%.

[0032] The test results of the embodiment of the present invention: after cleaning, the transmembrane pressure difference was restored from -70kPa to -10kPa during the operation of the ultrafiltration membrane, the permeate flux was 100% restored to the design flux, and the cleaning period was extended to 30 days.

[0033] The pollutants cannot be thoroughly cleaned by other cleaning methods, and the transmembrane pressure difference can only be restored to -35kPa, and the permeate flux can only be restored to 50% of the design flux, and the transmembrane pressure difference is restored rapidly after 4 days increased to -70kPa.

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PUM

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Abstract

The invention provides a cleaning method of an immersed ultrafiltration membrane. The method comprises the following steps: 1) carrying out primary alkali washing: emptying an ultrafiltration membranetank, conveying an alkaline cleaning solution into the ultrafiltration membrane tank until ultrafiltration membrane filaments are completely immersed in the cleaning solution, and carrying out soaking alkali washing on the ultrafiltration membrane; 2) backwashing the ultrafiltration membrane tank; 3) carrying out primary acid cleaning: emptying the ultrafiltration membrane tank, conveying an acidic cleaning solution into the ultrafiltration membrane tank to completely immerse ultrafiltration membrane filaments, and carrying out soaking and acid cleaning on the ultrafiltration membrane; 4) backwashing the ultrafiltration membrane tank; 5) carrying out secondary alkali washing: emptying the ultrafiltration membrane tank, conveying the alkaline cleaning solution into the ultrafiltration membrane tank until ultrafiltration membrane filaments are completely immersed, and carrying out soaking and alkali washing on the ultrafiltration membrane; 6) backwashing the ultrafiltration membrane tank; 7) carrying out secondary acid cleaning: emptying the ultrafiltration membrane tank, conveying the acidic cleaning solution into the ultrafiltration membrane tank till the ultrafiltration membranefilaments are completely immersed, and carrying out soaking and acid cleaning on the ultrafiltration membrane; and 8) backwashing the ultrafiltration membrane tank. The method has a remarkable recovery effect on cleaning of the ultrafiltration membrane polluted by multiple components at the same time and is excellent in working performance.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment and recycling, and in particular relates to a cleaning method for submerged ultrafiltration membranes. Background technique [0002] The submerged ultrafiltration is based on the hollow fiber ultrafiltration membrane module as the basic unit, and the membrane module is immersed in the ultrafiltration membrane pool. It is a design structure that sucks water from the outside to the inside under negative pressure. Membrane module is composed of ultrafiltration membrane. It is a basic unit integrating water collection and water production port. It is the core component of membrane device. Membrane module can have curtain type and column type. The membrane material is PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene) and other materials, which have strong chemical resistance and a wide range of applications. Submerged ultrafiltration has high tolerance to raw water quality and st...

Claims

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Application Information

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IPC IPC(8): C02F1/44B01D65/02
CPCB01D65/02C02F1/444C02F2303/14
Inventor 李瑞峰李治刚于守政
Owner LUTAI TEXTILE
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