Directing algal-bacterial interactions and system function with g-C₃N₄ under photostimulation

Area of Science:

• Environmental Biotechnology
• Materials Science
• Environmental Chemistry

Background:

• Wastewater treatment faces challenges with high carbon/nitrogen loads.
• Traditional methods are inefficient and energy-intensive.
• Need for sustainable, innovative solutions in wastewater management.

Purpose of the Study:

• To investigate graphitic carbon nitride nanoparticles (g-C3N4-NPs) for enhancing algal-bacterial wastewater treatment.
• To evaluate the impact of varying g-C3N4-NPs concentrations on system performance.
• To understand the role of g-C3N4-NPs in microbial community dynamics and system stability.

Main Methods:

• Algal-bacterial systems were treated with different concentrations of g-C3N4-NPs (0, 50, 100 mg/L).
• Wastewater treatment efficiency (COD, TN) was monitored.
• Microbial community dynamics, extracellular polymeric substance (EPS) production, and microbial aggregation were analyzed.
• Mechanistic studies explored electron transfer and microbial interactions.

Main Results:

• 50 mg/L g-C3N4-NPs (R2 system) significantly improved chemical oxygen demand and total nitrogen removal.
• g-C3N4-NPs promoted algal growth, increased EPS secretion, and enhanced microbial aggregation.
• Mechanistic insights revealed facilitated electron transfer and optimized microbial interactions by g-C3N4-NPs.
• The R2 system demonstrated enhanced stability and overall performance.

Conclusions:

• g-C3N4-NPs are effective in enhancing algal-bacterial wastewater treatment systems.
• The optimal concentration of 50 mg/L g-C3N4-NPs fosters a balanced ecosystem for efficient nutrient removal.
• Nanomaterials like g-C3N4-NPs offer a sustainable approach for environmental biotechnology applications.
• This study highlights the potential of g-C3N4-NPs in improving wastewater treatment with minimal energy input.