The S3A can support representative sample checks where the treatment configuration and sample meet its specification. The site’s procedure must determine the sampling point and phase; this article does not prescribe a universal SBR sampling time.
Define the phase in the site procedure
Use the same terminology as the plant’s operating records. If sampling is intended to represent a particular mixed-liquor condition, explain how the operator identifies that condition. Do not rely only on a broad shift label or an assumed cycle timetable.
Where a sampling time or phase changes, annotate the record. Preserve the old and new method labels so a difference caused by collection conditions is not automatically interpreted as a process change.
Separate reactor observations from the sample test
A settlement test takes place in the instrument’s sample tube. Its settled sludge level is not a measurement of sludge blanket depth in the full-scale reactor. Keep any tank observations separately labelled, even when they are reviewed together.
The S3A uses a representative 210 ml sample, measures MLSS in approximately 10 seconds and continues a 30-minute settlement cycle. The reactor’s operating sequence and the instrument’s test duration are different parts of the record.
Capture the comparison conditions
Sampling point and biological stage
Reactor phase at sample collection
Collection time and relevant cycle observations
MLSS and the connected settlement results
Unstirred SVI or optional stirred SSVI method
Any departure from the agreed routine
Check sample suitability before trending
Confirm that the expected MLSS fits the S3A’s specified 50 to 5,500 mg/L range, with stated accuracy of ±10%. Use a safe sampling location and the site’s approved preparation procedure. Ask PMA about unusual sample conditions before assuming suitability.
Compare results with site observations and relevant laboratory data. One sample does not diagnose the reactor or justify changing cycle settings. Follow the treatment team’s established review and escalation process.
Connect the sampling record to the S3A guides
Read the representative sampling guide and the settled volume versus SVI article for the comparison boundaries.
Review the S3A specification or contact PMA with the reactor configuration and proposed sampling phase. Required discharge monitoring and laboratory analysis remain separate.
