Bio-augmentation as a tool for improving the modified sequencing batch biofilm reactor

Area of Science:

• Environmental Science
• Microbiology
• Biotechnology

Background:

• Domestic sewage treatment faces challenges with low C/N ratios.
• Biological treatment methods are crucial for effective wastewater management.
• Biofilm reactors offer potential for enhanced contaminant removal.

Purpose of the Study:

• To evaluate the efficacy of a bio-augmented sequencing batch biofilm reactor (SBBR) for domestic sewage treatment.
• To assess the impact of indigenous bacterial consortium on contaminant removal.
• To investigate the performance of SBBR under short hydraulic residence time.

Main Methods:

• Utilized a pilot-scale modified SBBR with fibrous and ceramsite media.
• Employed a consortium of 5 indigenous bacterial strains (Pseudomonas and Bacillus).
• Analyzed contaminant removal using chemical oxygen demand (COD), total phosphorus (TP), and total nitrogen (TN) metrics.
• Applied Polymerase Chain Reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) to monitor bacterial survival and dominance.

Main Results:

• The SBBR achieved a short hydraulic residence time of 10 hours.
• Bio-augmentation significantly improved removal efficiencies: COD from 80.3% to 83.7%, TP from 58.1% to 67.8%, and TN from 41.3% to 58.7%.
• PCR-DGGE confirmed the survival of augmented strains, with Bacillus cereus ZQN2 identified as the most dominant.

Conclusions:

• Bio-augmented SBBR is effective for treating low C/N ratio domestic wastewater.
• Indigenous bacterial consortia enhance the removal of key pollutants, particularly total nitrogen.
• The study demonstrates the successful application and microbial stability of bio-augmented biofilm systems.