An inexpensive, reproducible method to quantify activated sludge foaming potential: Validation through lab-scale...

Area of Science:

• Environmental Microbiology
• Water Treatment Engineering
• Wastewater Management

Background:

• Activated sludge processes in water resource recovery facilities (WRRFs) are crucial for removing biochemical oxygen demand (BOD) and total suspended solids (TSS).
• Foaming is a prevalent operational issue in activated sludge, negatively impacting treatment efficiency, causing maintenance challenges, and posing environmental health risks.
• The biological and chemical drivers of stable foaming, such as specific microbes and surfactants, are complex and difficult to predict or quantify.

Purpose of the Study:

• To develop and validate an inexpensive, user-friendly method for quantifying foaming potential in activated sludge.
• To investigate the correlation between microbial community composition, functional parameters, and foaming events over a year-long study.
• To identify specific microbial genera associated with foaming events for improved prediction and mitigation strategies.

Main Methods:

• Development of a reproducible method to measure foaming potential using linear alkylbenzene sulfonate (LAS) as a benchmark.
• A year-long, full-scale study at South Shore Water Reclamation Facility (Oak Creek, WI) collecting activated sludge samples.
• Analysis of microbial community composition and functional parameters, including soluble total nitrogen, alongside foaming potential measurements.

Main Results:

• The developed foaming potential method demonstrated reproducibility (RSD <20%) and sensitivity to foam-inducing constituents.
• Higher relative abundance of genera Zoogloea, Flavobacterium, Variovorax, and Bdellovibrio were significantly associated with foaming events.
• Foaming potential showed a positive correlation with soluble total nitrogen (ρ = 0.24), and Variovorax and Bdellovibrio were newly identified as correlating with foaming.

Conclusions:

• The new method provides a practical tool for WRRFs to quantify activated sludge foaming potential.
• Monitoring specific microbial genera (Zoogloea, Flavobacterium, Variovorax, Bdellovibrio) and soluble total nitrogen can aid in predicting and managing foaming events.
• Further research across multiple facilities is recommended to validate these findings and deepen the understanding of microbe-foaming relationships.