Material selection of MBBR media retention screen

1. Mechanical strength
Impact resistance:
Interception nets of different materials have different degrees of impact resistance. For example, interception nets made of stainless steel usually have higher strength and hardness, and can withstand larger water flow impact and collision of fillers. In the MBBR system, the flow of water and fillers will have a certain impact force on the interception net, especially when the system starts, stops or the flow changes greatly. If the impact resistance of the interception net is insufficient, deformation, rupture and other problems may occur, resulting in the loss of fillers and affecting the normal operation of the system.
Some interception nets made of plastic materials, such as polyethylene and polypropylene, are relatively light in weight and low in cost, but their impact resistance is relatively weak. When selecting materials, it is necessary to determine the appropriate interception net material based on the actual operation of the system and the impact load.
Abrasion resistance:
Due to the continuous flow and collision of fillers in the system, the interception net will be subject to certain wear. The wear resistance of the material determines the service life and maintenance frequency of the interception net. Interception nets made of stainless steel usually have good wear resistance and can resist long-term wear of fillers. Some interception nets made of plastic materials may wear, become thinner, or even break after long-term use.
For MBBR systems in high-wear environments, materials with higher wear resistance can be selected or surface treatment of the interception net can be performed, such as spraying wear-resistant coatings, to improve its wear resistance.

2. Corrosion resistance
Chemical corrosion resistance:
Sewage treatment environments usually contain various chemical substances, such as acids, alkalis, and salts, which can corrode the interception net. Interception nets made of different materials have different resistance to chemical corrosion. Stainless steel has good corrosion resistance and can maintain stable performance in most sewage treatment environments. Some interception nets made of plastic materials, such as polyethylene and polypropylene, also have certain corrosion resistance, but may experience aging and deformation in some highly corrosive environments.
If the sewage treatment contains high concentrations of corrosive substances, it is necessary to select materials with stronger corrosion resistance, such as special alloys, fiberglass, etc.
Anti-biological corrosion:
In MBBR systems, the growth of biofilms and the activity of microorganisms may also corrode the interception net. Some materials may be eroded or adsorbed by microorganisms, resulting in performance degradation. For example, some plastic materials may be decomposed by microorganisms or produce biofouling, affecting the permeability and interception effect of the interception net.
Metal materials such as stainless steel are relatively difficult to be corroded by microorganisms, but biofouling may also accumulate. When selecting materials, it is necessary to consider their ability to resist biocorrosion, or take corresponding anti-biofouling measures, such as regular cleaning and the use of bactericides.

3. Filtration performance
Aperture stability:
The aperture size of the interception net directly affects its filtration performance. The aperture stability of interception nets of different materials may vary during long-term use. Some materials may cause aperture changes due to thermal expansion and contraction, mechanical deformation or chemical corrosion, thereby affecting the filtration effect. For example, when the temperature changes greatly, the aperture of the interception net made of plastic may shrink or expand.
Stainless steel interception nets usually have good aperture stability and can maintain relatively stable filtration performance during long-term use. When selecting materials, it is necessary to consider the impact of aperture stability on filtration effect to ensure that the interception net can effectively intercept the filler without causing excessive resistance to the water flow.
Permeability:
The permeability of the material will also affect the performance of the interception net. Good permeability can ensure smooth water flow, reduce head loss, and improve the operating efficiency of the system. Interception nets of different materials have different permeabilities, which depends on factors such as the porosity and surface roughness of the material. For example, some plastic interception nets may have a higher porosity and better permeability, but relatively lower strength. Although the interception net made of stainless steel has higher strength, it may have a relatively low porosity and slightly worse permeability.
When choosing materials, it is necessary to comprehensively consider factors such as permeability and strength to ensure that the interception net can meet the filtration requirements without causing too much impact on the hydraulic performance of the system.

If you want to understand the impact of materials on the performance of MBBR media retention screens, you can contact BioCell Environmental Technology, we will do our best to help you!

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