Aerobic granulation with industrial wastewater in sequencing batch reactors

Area of Science:

• Environmental Science
• Biotechnology
• Wastewater Treatment

Background:

• Industrial wastewater from dairy product analysis poses treatment challenges.
• Sequencing batch reactors (SBRs) are effective for wastewater treatment.
• Granular sludge formation is crucial for efficient wastewater treatment.

Purpose of the Study:

• To investigate granular sludge formation in SBRs fed with dairy industrial wastewater.
• To evaluate the impact of an anoxic phase and operational parameters on nitrogen removal and effluent quality.
• To determine optimal conditions for minimizing total suspended solids (TSS) in SBR effluent.

Main Methods:

• Two laboratory-scale SBRs (R1 and R2) were operated with industrial wastewater.
• R1 included an anoxic phase, while R2 was fully aerobic.
• High organic and nitrogen loading rates were applied.
• Effluent TSS was analyzed concerning withdrawal period and CODp/VSS ratio.

Main Results:

• Granular sludge with similar morphology and size distribution (0.25–4.0 mm) formed in both reactors.
• Both SBRs achieved 70% nitrogen removal efficiency despite different operational phases.
• Lower effluent TSS concentrations (<0.12 g COD/g VSS) were achieved with a reduced CODp/VSS ratio.
• Decreasing the withdrawal period from 3 to 0.5 min significantly reduced effluent TSS.

Conclusions:

• Granular sludge can be effectively formed in SBRs treating dairy industrial wastewater.
• Nitrogen removal efficiency is maintained even with operational variations.
• Minimizing effluent TSS requires careful control of the withdrawal period and CODp/VSS ratio.
• Shorter withdrawal periods enhance biomass retention and reduce effluent solids.