[Inhibitory Effect of Phenol on Phosphorus Removal Performance of an EBPR System]

Area of Science:

• Environmental Science
• Environmental Engineering
• Microbiology

Background:

• Enhanced biological phosphorus removal (EBPR) systems are crucial for wastewater treatment.
• Phenolic compounds are common industrial pollutants that can impact biological treatment processes.

Purpose of the Study:

• To investigate the inhibitory effects of varying phenol concentrations on EBPR performance.
• To understand the impact of phenol on COD and phosphorus removal, sludge characteristics, and recovery potential.

Main Methods:

• Operation of an SBR reactor with controlled phenol concentrations (5-200 mg·L^-1).
• Monitoring of COD and PO₄^3--P removal efficiencies.
• Assessment of sludge bulking and phosphate uptake/release dynamics.

Main Results:

• Phenol concentrations ≤ 50 mg·L^-1 maintained high COD and phosphorus removal (>85%).
• Concentrations > 100 mg·L^-1 drastically reduced phosphorus removal efficiency, with complete loss at 200 mg·L^-1 after 22 cycles.
• Inhibition of aerobic phosphate uptake was more severe than anaerobic release; high phenol induced difficult-to-recover sludge bulking.

Conclusions:

• Phenol concentrations above 100 mg·L^-1 severely impair EBPR system performance.
• The inhibitory effect of phenol on phosphorus removal is reversible at lower concentrations but leads to persistent issues at higher levels.
• Acclimation to low phenol levels can mitigate some negative impacts, but high concentrations cause irreversible sludge bulking.