Biological phosphorus removal in sequencing batch reactor with single-stage oxic process

Area of Science:

• Environmental Science
• Environmental Engineering
• Microbiology

Background:

• Biological phosphorus removal (BPR) traditionally relies on an anaerobic phase for enhanced biological phosphorus removal (EBPR).
• Sequencing batch reactors (SBRs) are versatile bioreactors used in wastewater treatment.
• Investigating alternative BPR strategies is crucial for optimizing wastewater treatment processes.

Purpose of the Study:

• To investigate the efficacy of BPR in an SBR utilizing a single-stage oxic process.
• To determine if BPR can be achieved without the conventional anaerobic phase.
• To understand the mechanisms of phosphorus uptake and storage under oxic conditions.

Main Methods:

• Experiments were conducted using simulated municipal wastewater in an SBR.
• The reactor operated with a single-stage oxic process.
• Key parameters such as dissolved oxygen (DO), pH, and influent phosphorus concentration were controlled and monitored.

Main Results:

• Significant BPR was achieved, with effluent phosphorus concentrations between 0.22-1.79 mg L⁻¹, representing over 90% removal efficiency.
• Phosphorus was primarily stored intracellularly as polyphosphate (poly-P).
• Poly-beta-hydroxyalkanoates (PHA) levels remained low, indicating phosphorus removal occurred without significant energy storage accumulation.

Conclusions:

• BPR is feasible in an SBR with a single-stage oxic process, challenging the necessity of an anaerobic phase.
• Phosphorus removal is driven by polyphosphate accumulation, not PHA synthesis, in this configuration.
• This approach offers a potential alternative for net phosphate removal in wastewater treatment.