What causes MBBR retention screens to fail?

Prolonged immersion in wastewater causes gradual degradation due to chemical corrosion or oxidation. Polymer materials may become brittle and crack, while metals may rust, reducing structural strength. Continuous water flow can cause damage to aged areas, especially in environments with large temperature fluctuations, which accelerates material aging and shortens the equipment's service life.

When water flow rates suddenly increase or when biomass accumulates in large quantities, the retention screen can experience impact forces beyond its design, causing frame deformation or screen cracking. Welding defects in the integral frame structure can lead to cracking in areas subject to concentrated stress. Insufficient mesh spacing can cause additional pressure due to impurities clogging the screen, further exacerbating structural damage.

If the retention screen is not securely fastened during installation, it can sway under the impact of the water flow, and long-term friction with the tank body can cause edge wear. Insufficient buffer space will prevent the equipment from absorbing the impact of sudden changes in water flow, while poorly sealed joints can cause localized corrosion due to the infiltration of impurities, compromising overall structural stability.

Failure to regularly clean biofilm and impurities attached to the surface can lead to uneven water distribution, increased localized pressure, and deformation of the screen. Failure to promptly replace aging seals can cause wastewater leakage and corrode equipment joints. Using hard tools during cleaning can scratch the screen surface, reducing its impact resistance.

High concentrations of acids, bases, or heavy metal ions in wastewater can corrode the retention screen material, causing rust and perforation on metals and swelling and deformation on polymer materials. High levels of suspended particulate matter in the water can exacerbate wear on the screen surface, while microbial metabolites can also degrade the material.

Failure to properly control the water flow rate during system startup or shutdown can cause a water hammer effect that impacts the retention screen, leading to loosening or damage. Failure to take proper protective measures during maintenance can cause equipment deformation due to collisions with tools or crushing with heavy objects. Unauthorized adjustment of operating parameters that results in excessive loads can also accelerate damage to the retention screen.