A defined role in your monitoring routine.
S3A suitability depends on the representative sample and the measurement required, rather than the process name alone. Discuss the sludge characteristics and expected concentration with PMA before specification.
Where the collected sample meets the instrument requirements, MLSS and settlement observations can contribute to an established operational routine. The S3A does not measure nitrogen conversion or diagnose biological activity.
From a representative sample to a recorded result.
Prepare the sample
Collect a representative sample using the site’s procedure. Use a 210 ml sample and confirm that the expected MLSS is within the specified 50–6,500 mg/L range. Readings above 6,500 mg/L are indicated as INF.
Run the test
S3A provides an MLSS result in approximately 10 seconds, followed by a 30-minute unattended settlement cycle. Standard outputs include SVI, settled sludge level, supernatant clarity and floating sludge.
Review in context
Review completed measurements alongside the sample identity and site observations. Store up to 28 completed results for each of three internal locations, with date and time.
Define the measurement required
Explain the process, sample characteristics and existing operating checks. Confirm which published S3A outputs are useful for the question the site is trying to answer.
Calibration and optional measurements
Calibrate with a site-specific sample of known MLSS between 2,000 and 4,000 mg/L. Repeat after large changes in sludge characteristics. SSVI and SSSL require the optional stirrer module.
Optional connection to a client system.
Specify optional MODBUS RTU over two-wire RS-485 when ordering. Read functions 03/04 provide supported readings to a compatible client system; dashboards and integration are client-provided. Function 06 is limited to Holding Register 40001 for the slave ID (1–247), not measurement writes or test control.
Operational measurement, not a replacement for required laboratory analysis.
S3A supports operational checks of activated sludge. Required compliance sampling, regulatory testing and laboratory analysis must still follow the procedures that apply to the site.
Operate indoors in a safe area at 0–45°C, in noncondensing conditions and away from direct and reflected sunlight. Follow the current manual and the treatment works’ safety and sampling procedures.
Continue your application review.
Measurement parameters
Explore the S3A measurement parameters for activated sludge, including MLSS, SVI, settled sludge level, supernatant clarity and floating sludge.
Explore guideS3A product details
Explore the portable S3A suspended solids and MLSS analyser for activated sludge: 210 ml sample, rapid MLSS result and 30-minute settlement cycle.
Explore guideContact PMA
Contact PMA UK to discuss S3A applications, product information, demonstrations, technical support, calibration and wastewater settlement testing.
Explore guide