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A high-recovery, pollution-resistant reverse osmosis membrane water treatment method

A technology of reverse osmosis membrane and high recovery rate, applied in water/sewage multi-stage treatment, water/sludge/sewage treatment, chemical instruments and methods, etc. Deal with complex problems to achieve the effect of low-cost continuous operation, pollution reduction, and recovery rate increase

Inactive Publication Date: 2017-04-12
SHANGHAI LEZE ENVIRONMENTAL ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These requirements make the pretreatment very complicated, and the technology requires that the pH should be operated above 10, which also greatly reduces the operating life of the reverse osmosis membrane
Another shortcoming of this technology is long-term operation at high pH. Some organic substances that may be precipitated at high pH will continue to concentrate and contaminate reverse osmosis. These substances include most organic tertiary ammonia and ketone organic substances.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The comprehensive wastewater of a coal chemical plant is composed of circulating water sewage and biochemically treated gas washing water. Among them, the COD is about 50ppm, the total silicon is about 50ppm, the total hardness is about 800ppm, and the conductivity is about 3000us. The wastewater is first chemically softened and clarified, with a total hardness of 120 ppm, and then filtered through sand filtration and continuous ultrafiltration. The turbidity of the effluent is 0.1NTU, and the SDI is 2. The water then passes through the automatic acid addition adjustment system and enters the first stage. For RO treatment, the concentrated water pH control period is 2 hours, and the PH-time curve within the 2-hour period is a step curve, where PH=5 takes 30 minutes, PH=6 takes 30 minutes, PH=9 takes 30 minutes, and PH=10.5 Go through 30 minutes. The water production rate of the reverse osmosis system is 83%, the conductivity of the product water is about 80us, and the COD...

Embodiment 2

[0034] The concentrated water produced in Example 1 was collected in the concentrated water tank, slightly turbid, with a pH of about 8. After sand filtration, the pH was adjusted to 10.5 with caustic soda. It was found that a small amount of flocs appeared. After ultrafiltration, The indicators measured are: COD is about 200ppm, total hardness is about 200ppm, conductance is about 15000us, total silicon is about 120ppm, and pH is about 10.5. The water then passes through the automatic acid-adding adjustment system and enters the second-stage RO treatment. The PH control period of the concentrated water is 2 hours, and the PH-time curve within the 2-hour period is a step curve, in which it takes 40 minutes at PH=5, and PH=6 For 20 minutes, PH=9 for 20 minutes, and PH=10.5 for 40 minutes. The water production rate of the reverse osmosis system is 70%, the conductivity of the product water is about 900us, and the COD of the product water is about 10. It has been running continu...

Embodiment 3

[0036] The comprehensive wastewater of a refinery chemical plant is composed of circulating water sewage and biochemically treated domestic sewage, of which COD is about 30ppm, total silicon is about 50ppm, total hardness is about 500ppm, and conductivity is about 2800us. The wastewater is chemically softened and clarified first, with a total hardness of 110 ppm, and then filtered through sand filtration and continuous ultrafiltration. The turbidity of the effluent is 0.1NTU, and the SDI is 2. The water then passes through the automatic acid addition adjustment system and enters the first stage. For RO treatment, the PH control period of the concentrated water is 4 hours, and the PH-time curve within the 4-hour period is a sinusoidal curve, where the bottom of the valley is PH=5, the peak of the valley is PH=11, and the median is PH=8. The reverse osmosis system produces The water rate is 85%, the conductivity of the produced water is about 60us, and the COD of the produced wat...

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Abstract

The present invention relates to a high recovery rate and pollution resistance reverse osmosis membrane water treatment method, which comprises that: 1) hardness of a sewage water body requiring treatment is removed, wherein the water body hardness (calculated as calcium carbonate) is less than 200 ppm; 2) clarifying and filtering are performed, wherein the turbidity of the sewage requiring treatment is less than 1, and SDI is less than 2; 3) the pH value of the influent is continuously adjusted according to a certain rule, and then the influent enters a reverse osmosis operation unit; and 4) reverse osmosis continuous operates to obtain the relatively clean desalted product water and the concentrated solution. The high recovery rate and pollution resistance reverse osmosis membrane water treatment method has the following advantages that: with the periodic change of the pH value, bacterial and other microorganisms in the water body almost impossibly survive so as to substantially reduce pollution caused by bacterial and secretions thereof; the pollution on the reverse osmosis membrane is avoided so as to substantially increase the recovery rate, wherein the recovery rate of the two-stage reverse osmosis co-treatment for the reclaimed water reuse can achieve more than 95%; and the weak link of the reverse osmosis membrane water treatment technology is overcome, such that the reverse osmosis membrane can continuously operate in an efficient and low-cost manner.

Description

technical field [0001] The invention relates to a method for treating polluted water with a reverse osmosis membrane (RO), in particular to a water treatment method with a high recovery rate and pollution-resistant reverse osmosis membrane. The water treatment method can effectively prevent the reverse osmosis membrane from being polluted when treating certain polluted water bodies, and can operate continuously with high efficiency and low cost, and can obtain clean water to the maximum extent. Background technique [0002] In the existing technology, reverse osmosis membrane water treatment technology can remove bacteria, viruses, colloids, organic matter and more than 98% of soluble salts, compounds with a molecular weight greater than 100, colloids and other substances in water to obtain relatively pure water. After nearly 40 years of development, reverse osmosis has become the most important technical equipment for water desalination and pure water production. In the pas...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/04
Inventor 张军吕文玉黄义忠
Owner SHANGHAI LEZE ENVIRONMENTAL ENG
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