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Method for cleaning immersed ultrafiltration membrane in wastewater reuse

An ultrafiltration membrane, immersion technology, applied in the field of filter membrane cleaning and reuse, can solve the problems of decreased membrane flux, decreased water production rate, increased transmembrane pressure difference, etc.

Active Publication Date: 2014-07-30
SHANXI TAIGANG STAINLESS STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Oil that has not been biochemically treated enters the ultrafiltration membrane system, and it is easy to form an oil film on the membrane surface, blocking the membrane pores, resulting in a decrease in membrane flux, a decrease in water production rate, and an increase in transmembrane pressure difference
Ordinary pickling or alkali cleaning cannot quickly and effectively restore its performance, which requires continuous improvement of chemical cleaning methods during operation practice and targeted cleaning

Method used

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  • Method for cleaning immersed ultrafiltration membrane in wastewater reuse
  • Method for cleaning immersed ultrafiltration membrane in wastewater reuse
  • Method for cleaning immersed ultrafiltration membrane in wastewater reuse

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0065] Embodiment 1: Adopt single alkaline washing method to clean submerged ultrafiltration membrane

[0066]When cleaning, the hot water pool is filled with water, the temperature is heated to 35°C, and the backwash pump of the ultrafiltration unit is started. After backwashing, the water in the membrane pool is discharged to 1.1~1.2 meters, and the hot water pump is started to inject hot water and cleaning agents into the ultrafiltration unit. In the membrane pool, after the water level reaches 2.2~2.3 meters, the hot water pump stops, and the ultrafiltration permeate pump starts to perform self-circulation.

[0067] Specifically include the following steps:

[0068] (1) Backwash

[0069] ①Close the water inlet valve of the ultrafiltration device, and continue to filter until the liquid level in the membrane pool reaches 1.2 meters;

[0070] ②The inlet pressure of the ultrafiltration device is 1.5bar<p<2.5bar, air and water enter the membrane pool at the same time, th...

Embodiment 2

[0087] Embodiment 2: Adopt single pickling method to clean submerged ultrafiltration membrane

[0088] Specifically include the following steps:

[0089] (1) Backwash

[0090] ①Close the water inlet valve of the ultrafiltration device, and continue to filter until the liquid level in the membrane pool reaches 1.1 meters;

[0091] ②The inlet pressure of the ultrafiltration device is 1.5bar<p<2.5bar, air and water enter the membrane pool at the same time, the air scrubbing time is 35 seconds, and the water level is increased to 2.2 meters. After the air scrubbing is completed, the sewage inside the ultrafiltration device is drained ;

[0092] (2) Acid chemical cleaning and medicine soaking

[0093] ① The membrane tank is fed with water by the hot water pump. During this process, the hydrochloric acid and citric acid metering pumps are started, and the pH is flexibly adjusted to 2 according to the online pH meter;

[0094] ② After the dosing is completed, soak for 30 minutes....

Embodiment 3

[0105] Embodiment 3: adopt alkali cleaning and pickling method to clean submerged ultrafiltration membrane

[0106] (1) Backwash

[0107] ①Close the water inlet valve of the ultrafiltration device, and continue to filter until the liquid level in the membrane pool reaches 1.2 meters;

[0108] ②The inlet pressure of the ultrafiltration device is 1.5bar<p<2.5bar, the air and water enter the membrane pool at the same time, the air scrubbing time is 30 seconds, and the water level is increased to 2.3 meters. After the air scrubbing is completed, the sewage inside the ultrafiltration device is drained ;

[0109] (2) Chemical cleaning and medicine soaking

[0110] ① The membrane tank is fed with water by the hot water pump. During this process, the sodium hypochlorite metering pump is started, and the pH is flexibly adjusted to 12 according to the online pH meter;

[0111] ② After the dosing is completed, soak for 45 minutes.

[0112] (3) Ultrafiltration cleaning cycle

[0113]...

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Abstract

The invention discloses a method for cleaning an immersed ultrafiltration membrane in wastewater reuse. The method comprises the following step of chemical cleaning. The method is characterized in that the step of chemical cleaning comprises the following substeps of alkali cleaning, acid cleaning or combined alkali cleaning and acid cleaning, wherein each of the alkali cleaning method and the acid cleaning method is of a method combining the circulatory cleaning with the immersed cleaning, and an alkali cleaning agent comprises sodium hypochlorite, sodium dodecyl benzene sulfonate and sodium tripolyphosphate; an acid cleaning agent comprises citric acid, hydrochloric acid and oxalic acid. The method has the advantages that sodium dodecyl benzene sulfonate and sodium tripolyphosphate are added in the process of alkali cleaning by sodium hypochlorite, so that the cleaning effect of the method on ultrafiltration organic matters and oil pollutants is obviously better than that of a normal alkali cleaning method, the polluting and plugging degree of the cleaned ultrafiltration membrane can be reduced, and stability in operation can be realized; the acid cleaning is adopted as required after alkali cleaning, and the oxalic acid agent is added in the process of acid cleaning, so that the ultrafiltration membrane can be thoroughly cleaned, and the produced water flow and the running differential pressure of the ultrafiltration membrane can be recovered to be the optimal effect.

Description

technical field [0001] The invention relates to a cleaning method for submerged ultrafiltration membranes in sewage reuse, and belongs to the technical field of filter membrane cleaning and reuse. Background technique [0002] In the 21st century, industrialization and urbanization have degraded the global environment, leading to serious resource shortages and environmental pollution. Water resources are one of them. [0003] Industrial water accounts for about 70% of the national urban water use, and industrial production water discharges a large amount of industrial wastewater, which is also the main source of water pollution. In the past 30 years, the development of ultrafiltration technology has been extremely rapid, and its application in sewage reuse has become more and more extensive. It has made great contributions to reducing sewage discharge, reducing the load on natural water bodies, opening up sources of income and reducing expenditure, and reducing fresh water ...

Claims

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Application Information

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IPC IPC(8): B01D65/02B01D65/06
Inventor 张芬芳赵艳芳
Owner SHANXI TAIGANG STAINLESS STEEL CO LTD
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