How to select an online MLSS or suspended-solids analyzer
Choose by the actual solids duty—effluent TSS, mixed liquor or concentrated sludge—not by one generic mg/L range.
The selection in one paragraph
Define whether the measurement is effluent suspended solids, aeration-basin MLSS, return sludge or concentrated sludge. Then confirm minimum, normal and peak solids, homogeneity, bubbles, fouling, velocity, pressure, cleaning and mounting.
Confirm these conditions before choosing a model.
TSS, MLSS or sludge concentration?
The expected range and matrix can differ by orders of magnitude.
What are the minimum, normal and peak values?
Use real operating data and note whether values are laboratory dry-weight equivalents.
Is the sludge consistently mixed?
Settling, ragging and air bubbles can make a local optical reading unrepresentative.
Are color or bubbles significant?
Confirm the stated optical method and whether the site needs a process-specific correlation.
How quickly will the window foul?
Automatic cleaning and accessible mounting reduce maintenance but do not remove the need for inspection.
How will readings be correlated?
Plan a site correlation against representative laboratory samples across the operating range.
Select by solids range and process point
Separate MLSS from effluent TSS
MLSS in an aeration basin is a process-control measurement in a highly aerated, biologically active matrix. Effluent TSS is usually much lower and may be used for discharge or treatment-performance monitoring. One sensor family may cover both only when the selected range, installation and site correlation are suitable.
Mount the sensor where mixed liquor is representative and where it can be safely removed for cleaning. Avoid walls, dead zones and locations dominated by large air bubbles.
RFQ checklist
Supply the actual process conditions rather than only the words ‘sludge sensor’.
- Process point and measurement objective
- Minimum, normal and peak mg/L
- Laboratory method used for correlation
- Sludge type, color, bubbles and homogeneity
- Pressure, velocity and immersion depth
- Cleaning method and access
- Cable, output, controller and installation hardware
Products to compare after the duty is defined.
Wide-Range Suspended Solids / Sludge Analyzer
The primary option when a broad solids range or higher sludge concentration must be covered.
View technical data↗Suspended Solids / Sludge Analyzer
A compact online configuration for defined wastewater solids duties.
View technical data↗Real suspended-solids and sludge projects
Review municipal, industrial and river-corridor installations documented with searchable English case content.
Questions buyers ask before quotation.
Is MLSS the same as suspended solids?+
MLSS is the concentration of suspended solids in mixed liquor, typically in biological wastewater treatment. TSS is a broader term. The process matrix and expected range must be specified.
Does an optical MLSS sensor need site calibration?+
A site correlation against representative laboratory samples is normally advisable because sludge optical properties and process conditions differ.
Where should an MLSS sensor be installed?+
Use a representative, well-mixed location with safe access for cleaning. Avoid dead zones, walls and positions dominated by large air bubbles.