Biodegradation and optimization of bilge water in a sequencing batch reactor using response surface methodology

Area of Science:

• Environmental Microbiology
• Marine Pollution Control
• Bioreactor Technology

Background:

• Bilge water is a major marine pollutant, necessitating effective treatment strategies.
• Chemical Oxygen Demand (COD) is a key indicator of organic pollution in marine environments.
• Sequencing Batch Reactors (SBRs) offer a flexible approach for wastewater treatment.

Purpose of the Study:

• To assess the biodegradation of Chemical Oxygen Demand (COD) in bilge water using a sequencing batch reactor (SBR).
• To optimize SBR performance for bilge water treatment by identifying optimal operating conditions.
• To investigate the biodegradation kinetics of COD in bilge water.

Main Methods:

• Utilized a sequencing batch reactor (SBR) inoculated with Bacillus licheniformis (strain S2).
• Employed Response Surface Methodology (RSM) to optimize temperature, pH, and inoculum concentration.
• Analyzed biodegradation kinetics using the first-order equation.

Main Results:

• Achieved a maximum COD removal efficiency of 77.81% at optimal conditions: 35.44°C, pH 8.13, and 31.47 mL inoculum.
• Observed a decrease in COD degradation rate with reduced hydraulic retention time (HRT).
• Biodegradation kinetics followed a first-order equation with a high coefficient of determination (R² = 0.98106).

Conclusions:

• The SBR system, optimized by RSM, is effective for biodegrading COD in bilge water.
• Optimized operating parameters are crucial for maximizing COD removal efficiency.
• First-order kinetics accurately describe COD biodegradation in bilge water within the SBR system.