The parameter at a glance.
MLSS represents the concentration of suspended solids in mixed liquor. The S3A provides a rapid operational result with stated accuracy of ±10%.
mg/L
Unit or result
Approximately 10 seconds
Test timing
50 to 6,500 mg/L
S3A scope
Understanding Mixed Liquor Suspended Solids (MLSS).
MLSS represents the concentration of suspended solids in mixed liquor. The S3A provides a rapid operational result with stated accuracy of ±10%.
What MLSS shows
MLSS supports routine comparison of biomass and suspended-solids concentration against the treatment works’ established operating range.
Use the same sample
The MLSS result comes from the same representative 210 ml sample used for the subsequent settlement cycle.
Review the trend
Compare results over time and alongside the site’s wider process information rather than interpreting one reading in isolation.
One sample. A complete settlement picture.
The S3A measures MLSS rapidly, then continues the unattended 30-minute settlement test for SVI, SSL, supernatant clarity and floating sludge. The optional stirrer is required for SSVI and SSSL.
01 / MLSS
Rapid MLSS measurement
A result in approximately 10 seconds from a compact 210 ml sample, within the specified 50 to 6,500 mg/L range.
02 / Settlement test
Unattended settlement analysis
The analyser continues the 30-minute cycle and stores the completed result after the test has finished.
Designed for routine activated-sludge checks.
The S3A uses a compact 210 ml representative sample in a safe-area wastewater-treatment environment. The 30-minute settlement cycle runs unattended, allowing the operator to continue with other work.
Completed results can be stored for each of three locations, with date and time information.
Explore related S3A parameters.
See how the S3A measurements work together within one repeatable settlement-analysis workflow. The portable suspended solids analyser guide explains where this rapid MLSS result fits the full instrument cycle.
Sludge Volume Index (SVI)
Relate settled sludge volume to MLSS concentration after the S3A completes its 30-minute settlement test.
Settled Sludge Level (SSL)
Record the volume occupied by activated sludge after the S3A completes the unattended 30-minute settlement cycle.
Supernatant Clarity
Assess the solids remaining above the settled sludge after the unattended 30-minute S3A settlement cycle.