Pin Floc / Deflocculation
Small, weak floc particles fail to settle, leaving a cloudy, turbid effluent.
Symptoms: tiny, dispersed floc particles visible under the microscope with little structure; effluent appears hazy or turbid despite a clear settling test on larger particles.
Probable Causes: excessively long SRT/over-oxidation, high shear from over-mixing or excess DO, or a toxic shock load damaging floc structure.
Troubleshooting Steps: 1) Check SRT — if it's running unusually high, increase wasting to bring it back into the normal operating range. 2) Reduce excess turbulence from over-aeration or aggressive mixing. 3) Screen for a possible industrial toxic discharge upstream if the change was sudden. 4) Give the system 1-2 sludge ages after correction; floc structure typically rebuilds gradually, not overnight.
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