How to control common reverse osmosis membrane fouling

How to control common reverse osmosis membrane fouling

During the long-term treatment of water quality, the reverse osmosis membrane of purified water equipment may be contaminated, resulting in a decrease in the performance of the reverse osmosis membrane and ultimately affecting the effluent quality of the purified water equipment. So in the process of using equipment, we need to do a good job in controlling reverse osmosis membrane pollution. So, how to control reverse osmosis membrane pollution in common purified water equipment?

1、 Adsorption pollution

The adsorption of organic matter on the surface of reverse osmosis membranes is usually the main factor affecting membrane performance. Over time, the adsorption or accumulation of pollutants within the membrane pores can lead to a decrease in pore size and an increase in membrane resistance, which is difficult to recover. Humic acids and other natural organic compounds (NOM) have a greater impact on permeability than clay or other inorganic particles, even at lower concentrations.

Adsorption pollution and the stability of gel layer formed by organic matters in water affect the efficiency of cleaning. The cleaning methods include backwashing, rapid pulse or cross flow backwashing. Reagents used for membrane chemical cleaning must be able to effectively dissolve organic compounds in the gel layer.

2、 Sedimentation pollution

Membrane separation technologies driven by pressure include reverse osmosis (R0), nanofiltration (NF), ultrafiltration (UF), and microfiltration (MF). When the concentration of salt in the raw water exceeds its solubility, precipitation or scaling will form on the membrane. The pollutants of widespread concern are the precipitates of calcium, magnesium, iron, and other metals, such as hydroxides, carbonates, and sulfates.

The main method to avoid precipitation pollution is to reduce the concentration of cations or anions in the ion product. For example, adding acids can reduce the concentration of hydroxides and carbonates, making it difficult to generate metal ion precipitation. Raw water can be pretreated by lime softening precipitation or ion exchange to remove metal ions (such as Ca2+, Mg2+, etc.) that are prone to scaling. Scale inhibitors, such as hexamethyl phosphate, can also be added to hinder precipitation formation

3、 Biological pollution

Biological pollution refers to the phenomenon of microorganisms accumulating at the membrane water interface, thereby affecting system performance. The interior of the membrane module is damp and dark, making it an ideal environment for microbial growth,

So once the biological activity level of the raw water is high, it is highly susceptible to membrane biological pollution. The biological fouling of membranes can be divided into two stages: adhesion and growth.

The above is the "Precautions for Selecting Stainless Steel Water Treatment Equipment" that Hongjie Water brings to you. We hope it can help you!

Shenzhen Hongjie Water Technology Co., Ltd. is an integrated high-tech enterprise specializing in product research and development, production, sales, engineering design, installation and debugging, technical consulting, and sales of supporting materials in the fields of industrial water treatment and drinking water treatment. Our main products include the design, manufacturing, installation, debugging, and maintenance of water treatment equipment, including pure water equipment, ultra pure water equipment, reverse osmosis equipment, GMP purified water equipment, EDI deionized water equipment, domestic sewage equipment, industrial wastewater equipment, softened water equipment, and reclaimed water reuse equipment, all of which are integrated into an environmentally friendly high-tech manufacturer.