Sludge Carryover
Settled Sludge Rising Into the Clarified Zone
Sludge carryover occurs when previously settled sludge is re-entrained and leaves with the effluent — usually a sludge-management or septicity problem.
Understanding the Problem
Unlike fresh solids carryover, sludge carryover involves already-settled material returning to suspension. The classic cause is a sludge blanket allowed to grow until it reaches the plates.
Septic sludge generates gas that floats sludge mats upward. Infrequent or ineffective desludging, or an undersized sludge system, are common contributors.
Restoring a disciplined desludge regime and eliminating septicity usually resolves it quickly.
Common Symptoms
- ›Dark, dense solids in effluent
- ›Sludge blanket rising over time
- ›Gas bubbles lifting sludge mats
- ›Deterioration between desludge cycles
Causes & Corrective Actions
Cause
Sludge blanket too high
Corrective Action
Desludge more frequently; add level-based blanket control.
Cause
Septic sludge producing gas
Corrective Action
Reduce sludge retention; address upstream septicity and odour.
Cause
Undersized or faulty sludge removal
Corrective Action
Service or upgrade the sludge pump/scraper; verify hopper geometry.
Cause
Hopper bridging or rat-holing
Corrective Action
Improve hopper slope; add fluidisation or agitation as needed.
Prevention
Related Pages
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