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Method for washing NF membranes and RO membranes

A technology of cleaning solution and acid cleaning solution, which is applied in the field of membrane fouling cleaning, can solve the problems of reduced service life, single chemical cleaning method, high cost of chemicals, etc., and achieve the effect of prolonging service life, simple process operation and good cleaning effect

Inactive Publication Date: 2019-01-18
HUNAN JUNXIN ENVIRONMENTAL PROTECTION CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the chemical cleaning agents currently on the market are general-purpose cleaning agents. The cost of the agents is high and the pertinence is not strong. It is troublesome to clean the membrane elements in sections and cannot meet the cleaning requirements of the landfill leachate NF / RO treatment process. More importantly, Yes, the negative impact on the NF / RO membrane is not considered or not fully considered, and the chemical cleaning method of the existing NF / RO membrane is relatively simple, and there are neglects in the cleaning sequence and cleaning parameter control, which is used for cleaning treatment When using NF / RO membranes for landfill leachate, the cleaning effect is often not good
When the existing chemicals and cleaning methods are combined with cleaning, the operating pressure of the NF / RO membrane often does not drop much, and it is easy to cause invisible damage to the NF / RO membrane and reduce the service life

Method used

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  • Method for washing NF membranes and RO membranes

Examples

Experimental program
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Effect test

Embodiment 1

[0040] In this example, the waste water from old landfill leachate is mixed with fresh leachate C / N ratio, then enters the MBR biochemical treatment, and then enters the ultrafiltration system to realize the separation of mud and water. After the ultrafiltration system separates mud and water, the obtained ultrafiltration The conductivity of the produced water is 13000-14000us / cm, the total hardness is 1000-3000mg / L, and the COD is 700-800mg / L. Treat the ultrafiltration product water and carry out mixed discharge to meet the discharge standard in Table 2 of GB16889-2008.

[0041] In this embodiment, the nanofiltration / reverse osmosis membrane used to treat landfill leachate is made of polyamide, which is a Dow membrane, and the reverse osmosis membrane model is SW30HRLE-370 / 34i; the nanofiltration membrane model is NF270-400, designed for nanofiltration / Reverse osmosis membrane advanced treatment of ultrafiltration product water.

[0042] In this embodiment, a thermometer is...

Embodiment 2

[0059]In this example, the waste water from old landfill leachate is mixed with the C / N ratio of fresh leachate, then enters the MBR biochemical treatment, and then enters the ultrafiltration system to realize the separation of mud and water. After the mud and water separation of the ultrafiltration system, the conductivity is 13000 ~14000us / cm, the total hardness is 1000~3000mg / L, COD700~800mg / L, the ultrafiltration product water is stored in a water storage tank, and then the ultrafiltration product water is treated with nanofiltration / reverse osmosis membrane for mixed discharge , to meet the emission standards in Table 2 of GB16889-2008.

[0060] In this embodiment, the nanofiltration / reverse osmosis membrane used to treat landfill leachate is made of polyamide, which is a Dow membrane, and the reverse osmosis membrane model is SW30HRLE-370 / 34i; the nanofiltration membrane model is NF270-400, designed for nanofiltration / Reverse osmosis membrane advanced treatment of ultra...

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Abstract

The invention discloses a method for washing NF / RO membranes. The method comprises the steps: S1. subjecting an NF or RO membrane to circulating alkali cleaning with an alkaline cleaning solution of specific ingredients, stopping circulating until the temperature of the cleaning solution reaches 38 DEG C to 39 DEG C, subjecting the membrane to soaking and cooling treatment, and then, continuing tocarry out circulating alkali cleaning, wherein a pH value is controlled to 10.5 to 11 during alkali cleaning; S2. carrying out first flushing on the membrane obtained in the step S1 with product water; S3. subjecting the membrane obtained in the step S2 to circulating acid cleaning with an acidic cleaning solution of specific ingredients, stopping circulating until the temperature of the cleaningsolution reaches 38 DEG C to 39 DEG C, subjecting the membrane to soaking and cooling treatment, and then, continuing to carry out circulating acid cleaning treatment, wherein a pH value is controlled to 2 to 3 during acid cleaning; and S4. carrying out second flushing on the membrane obtained in the step S3 with product water. According to the method, the damage to the membranes can be reduced,the process operations are simple, the pertinency of chemicals is high, the washing effect is good, and thus, the physicochemical properties and treatment capacity of the NF or RO membranes can be restored to the maximum.

Description

Technical field [0001] The invention relates to the field of membrane pollution cleaning, and in particular to a cleaning method for NF membranes and RO membranes. Background technique [0002] In aged leachate, B / C is low (that is, BOD in sewage 5 / COD ratio), has poor biodegradability and contains more organic matter that is not easily degraded. The NF / RO membrane is used to deeply treat MBR ultrafiltration water and must be chemically cleaned regularly during operation to maintain the designed operating pressure and output. Water yield. As the NF / RO membrane continues to operate, more pollutants will accumulate on the membrane surface. The membrane performance characteristics include a significant decrease in membrane flux, an increase in operating pressure, and a deterioration in effluent quality. After various surface pollutants block the water production channel of the NF / RO membrane, physical flushing alone cannot restore the membrane's water production yield and op...

Claims

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Application Information

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IPC IPC(8): B01D65/02
CPCB01D65/02B01D2321/162B01D2321/164
Inventor 高新周俊蔡斌肖宇轩田黎黎
Owner HUNAN JUNXIN ENVIRONMENTAL PROTECTION CO LTD
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