1Symptom
Effluent TSS rises above normal or toward the permit limit. Effluent may be cloudy (dispersed growth or pin floc) or show distinct particles (straggler floc, rising sludge, washout).
2Check first
- Look at the effluent sample: cloudy versus particles.
- Check blanket depths and SVI.
- Check settleometer supernatant clarity.
- Check weir condition and level.
- Check for algae on weirs and launders.
3Possible causes
- Pin floc or dispersed growth.
- Straggler floc.
- Rising sludge.
- Thickening overload (high blanket).
- Hydraulic overload.
- Uneven weirs, short circuiting, or algae.
4Next investigation
- Match the symptom to the pin floc, straggler, rising sludge or blanket guides.
- Check SOR and solids loading rate.
5Corrective actions
- Follow the matching guide.
- Clean weirs and launders.
- Level weirs.
- Use a polishing coagulant or polymer as a short term measure.
6When to call for help
- TSS limit is at risk.
- Cause is not clear after the checks above.
Make one change at a time, record it, and follow your plant procedures and permit. If you suspect a toxic discharge, a safety hazard or a permit violation, notify your supervisor right away.
This guide also appears on ActivatedSludge.com, our consulting site. Results are for training and operator use; always follow your plant’s procedures.