Part 4: 🌊 Troubleshooting High Sludge Blanket in Secondary Clarifierc. Excessive Hydraulic or Solids Loading 💦High inflow rates can overwh...
Published on by Hossein Ataei Far, Deputy Manager of the Research, Technology Development, and Industry Relations Center at NWWEC
c. Excessive Hydraulic or Solids Loading 💦
High inflow rates can overwhelm clarifier capacity. Solutions:
Surface Overflow Rate (SOR): Regularly evaluate and adjust clarifier design or operational limits.
Equalization Basins: Install or use to buffer peak flows.
References: 1, 3
B. Scum and Foam
Foaming can indicate system imbalances. Common scenarios and responses include:
1. White Billowing Foam ☁️
Often seen during startup or organic shocks:
Causes: High F:M ratio, CRT below target, or organic overload.
Actions: Adjust CRT or increase aeration to promote biomass stabilization.
References: 3, 4
2. Dark, Scummy Brown Foam 🛁
Indicative of prolonged CRT or excess oil and grease:
Causes: Extended aeration leading to higher biomass age or influent with excessive FOG.
Actions: Control CRT, remove FOG sources, and monitor primary influent quality.
References: 1, 3, 4
Keynote on Filamentous Bacteria
Deborah Lee, a microbiologist, highlights the role of Microthrix species in clarifier performance.
Key Filaments:Microthrix parvicella: Known for bulking and foaming issues in cold and warm temperatures.
Microthrix calida: Thrives at >30°C but does not cause foaming. This discovery expands our understanding of Microthrix's environmental flexibility.
Proactive Measures:
Increase wasting, adjust DO levels, and monitor nutrient levels to keep filament growth in check. Studies confirm the importance of consistent microscopic evaluation to effectively identify and manage bulking organisms.
References: 2, 3, 4
References 📚
[1] State of Michigan Department of Environmental Quality, Activated Sludge Process Control.
[2] AquaFix, Microthrix Bulking in Summer. Access Link
[3] Jenkins, Richard D., Manual on Activated Sludge Bulking and Foaming Problems.
[4] WEF (Water Environment Federation), filamentous bacteria in activated sludge.