Biofilm is essential to MBBR performance. But what happens when it starts detaching from the carriers?

Biofilm detachment is not always a problem. A certain degree of sloughing is a natural part of biofilm renewal. However, excessive detachment may indicate that something in the system needs attention.

Here are four common causes:

🔹 1. Excessive Shear Forces

Intense aeration or mixing can create strong mechanical forces that remove biofilm from the carrier surface.

🔹 2. Changes in Organic Loading

Sudden increases or decreases in wastewater loading can affect microbial growth and biofilm stability.

🔹 3. Poor Operating Conditions

Changes in dissolved oxygen, pH, temperature, or toxic substances may stress microorganisms and weaken biofilm development.

🔹 4. Excessively Thick Biofilm

When biofilm becomes too thick, oxygen and substrate may not reach deeper layers effectively, potentially causing internal decay and detachment.

What Should We Do?

Before changing the media, check aeration, mixing intensity, organic loading, and water quality. Identifying the root cause is more effective than simply adding more carriers.

A well-designed MBBR carrier provides a suitable surface for biofilm attachment, but stable biofilm also depends on proper process control.

The goal isn't to prevent all detachment—it's to maintain a healthy, active, and balanced biofilm.