High Turbidity After Plate Settler
Cloudy Effluent Diagnosis
High effluent turbidity usually points to fine particles escaping capture — often a chemistry, loading or distribution issue rather than a fault in the plates themselves.
Understanding the Problem
Turbidity is dominated by fine, slow-settling particles. If these are not agglomerated into larger flocs, their settling velocity falls below the surface loading rate and they are carried over.
The most common root cause is inadequate coagulation/flocculation — wrong dose, poor mixing or unstable pH. Hydraulic overloading and uneven flow distribution are the next most frequent culprits.
Work through chemistry first, then hydraulics, then mechanical condition. Small corrections to coagulant dose or flow often restore clarity without any hardware change.
Common Symptoms
- ›Cloudy or milky effluent
- ›Rising NTU / turbidity readings
- ›Fine, non-settling particles visible
- ›Turbidity spikes at peak flow
Causes & Corrective Actions
Cause
Insufficient or incorrect coagulant/flocculant dose
Corrective Action
Run jar tests and adjust dose; verify rapid-mix and flocculation conditions.
Cause
pH outside the coagulant’s effective range
Corrective Action
Correct pH to the optimum window for the coagulant in use.
Cause
Surface loading rate too high for the particles
Corrective Action
Reduce flow or add plate area; verify SLR against particle settling velocity.
Cause
Uneven flow distribution across the pack
Corrective Action
Inspect and clean the inlet distribution system; check for blockages.
Cause
Cold water increasing viscosity
Corrective Action
Derate the loading rate for low-temperature operation.
Prevention
Still seeing the problem?
Send us your operating data and effluent results. Our process engineers will diagnose the issue and recommend a corrective plan.