Filamentous bulking control by sponge media in lab-scale SBR process

Area of Science:

• Environmental Engineering
• Wastewater Treatment Technologies
• Biotechnology

Background:

• Filamentous bulking is a common operational problem in wastewater treatment, impairing sludge settling and overall process efficiency.
• Sequencing batch reactors (SBRs) are widely used for nutrient removal, but are susceptible to bulking issues.
• Effective control of filamentous bulking is crucial for maintaining stable and high-performance wastewater treatment.

Purpose of the Study:

• To investigate the efficacy of polyurethane foam sponge media in controlling filamentous bulking in an SBR.
• To evaluate the impact of sponge media on biomass settling properties and nutrient removal performance.
• To elucidate the mechanisms by which sponge media mitigate filamentous bulking.

Main Methods:

• A lab-scale sequencing batch reactor (20 L) was operated with synthetic wastewater (approx. 200 mgBOD/L).
• Polyurethane foam sponge media (20% v/v) were introduced into the reactor to assess their impact.
• Biomass settling properties, nutrient removal (Total Nitrogen and Total Phosphorus), and microscopic characteristics were analyzed.

Main Results:

• Incorporation of 20% v/v sponge media significantly improved biomass settling characteristics.
• Enhanced nutrient removal was achieved, with Total Nitrogen < 10 mg/L and Total Phosphorus < 1 mg/L, even at a short hydraulic retention time (HRT) of 0.67 days.
• Without sponge media, severe bulking led to significant biomass washout.

Conclusions:

• Polyurethane foam sponge media are effective in controlling filamentous bulking in SBRs.
• Sponge media enhance biomass settling and nutrient removal efficiency by physically fragmenting filaments and flocs.
• The physical breakdown of biomass by sponge media creates conditions conducive to suppressing filamentous bulking.