Biodegradation of pyridine in a completely mixed activated sludge process

Area of Science:

• Environmental microbiology
• Biotechnology
• Wastewater treatment

Background:

• Pyridine is a common industrial pollutant found in wastewater.
• Effective bioremediation strategies are needed to remove pyridine from contaminated water sources.
• Biomass development using specific bacterial strains is crucial for efficient degradation.

Purpose of the Study:

• To evaluate the performance of a completely mixed activated sludge (CMAS) reactor for pyridine biodegradation.
• To determine the optimal operating conditions for pyridine removal.
• To compute bio-kinetic constants for pyridine biodegradation in a continuous system.

Main Methods:

• Isolation and identification of a bacterial strain, Pseudomonas pseudoalcaligenes-KPN.
• Development of biomass in a CMAS reactor using the identified bacterial strain.
• Evaluation of pyridine degradation efficiency at various loading rates and hydraulic retention times (HRTs).
• Calculation of bio-kinetic parameters including yield coefficient (Y), decay coefficient (Kd), maximum growth rate constant (mumax), and saturation rate constant (Ks).

Main Results:

• Pyridine was efficiently degraded at a loading of 0.251 kg pyridine/kg MLSS/d and an optimal HRT of 24 hours.
• Pyridine served as the sole carbon and nitrogen source for the biomass, producing ammonia-nitrogen (NH3-N).
• Computed bio-kinetic constants were: Y = 0.29, Kd = 0.0011 d(-1), mumax = 0.108 d(-1), and Ks = 5.37 mg/L.

Conclusions:

• A CMAS system inoculated with P. pseudoalcaligenes-KPN is effective for pyridine biodegradation.
• Optimal conditions for pyridine removal were identified, enabling efficient wastewater treatment.
• The study provides valuable bio-kinetic data for the design and operation of bioreactors for pyridine-containing wastewater.