A sterilizing method for preventing microbial fouling from blocking reverse osmosis membranes

Abstract

The invention relates to a sterilization method capable of preventing a reverse osmosis membrane from being polluted and plugged by microbe. The sterilization method mainly comprises the steps of adding an oxidizing sterilizing agent NaClO (5%) solution to a raw water tank continuously; adding a reducing agent NaHSO3 (35% W / V) solution continuously after ultra-filtration; removing residual chlorine thoroughly; controlling a pH value of inlet water at a reverse osmosis inlet between 7.1 and 7.4; monitoring and controlling ORP before a security filter between 200 mv and 300 mv; and sterilizing by carrying out preventative addition of a non-oxidizing sterilizing agent DBNPA solution with a concentration of 50 ppm continuously for one hour once every week in the above flow according to the quick killing characteristic of the non-oxidizing sterilizing agent DBNPA. Meanwhile, NaClO addition to the raw water tank is stopped. The sterilization method mainly takes use of the oxidizing sterilizing agent accompanied by two non-oxidizing sterilizing agents to carry out preventative sterilization alternatively, controls drug tolerance and resistance of the microbe, can effectively prevent and control propagation and excessive multiplication of the microbe on the surface of the reverse osmosis membrane, thereby preventing the reverse osmosis membrane from being polluted and plugged by the microbe.

Description

technical field [0001] The application relates to the fields of using reverse osmosis technology in water treatment to produce boiler feed water and industrial desalinated water, and in particular to a sterilization method for preventing microbial fouling of reverse osmosis membranes. Background technique [0002] Reverse osmosis is a widely used desalination technology in the preparation of pure water equipment. Reverse osmosis (RO), ultrafiltration (UF), microporous membrane filtration (MF) and electrodialysis (EDI) technologies are all membrane separation technologies. [0003] The production of desalted water by pressurized membrane separation technology using reverse osmosis (RO) and ultrafiltration (UF) membranes is a typical process for boiler feed water and industrial pure water. Its technological process is briefly described as follows (as shown in the accompanying drawings): [0004] When production water enters the production area, it first enters the water stora...

AI Technical Summary

Problems solved by technology

[0006] In the process of using reverse osmosis technology to produce boiler feed water and industrial desalinated water, microbial fouling of reverse osmosis membranes often occurs and affects the normal operation of the device

Biofouling reverse osmosis membranes will have the following problems: 1) The biofouling of reverse osmosis membrane elements will seriously affect the performance of the reverse osmosis device, and the pressure difference between the feed water and concentrated water will increase rapidly, resulting in mechanical damage to the membrane elements, production water drop

2) Biofouling will also occur on the product water side of the membrane element, resulting in product water contamination

[0008] According to the product technical manual provided by the reverse osmosis membrane manufacturer, Dow Chemical Company's "Reverse Osmosis and Nanofiltration Component Product and Technical Manual 2012 Edition" 4-6 content requirements of the prevention of membrane biofouling chapters, according to the method described in the manual for sterilization treatment, in The problem of biological fouling of reverse osmosis membranes still occurs in practical applications

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