Micro-graphite particles accelerate denitrification in biological treatment systems.

Area of Science:

• Environmental Science
• Microbiology
• Chemical Engineering

Background:

• Accelerated denitrification is crucial for effective biological nitrogen removal from wastewater.
• Wastewater treatment processes often face challenges with slow denitrification rates.

Purpose of the Study:

• To investigate the effect of micro-graphite particles (MGPs) on accelerating denitrification.
• To elucidate the microbial mechanisms behind MGP-enhanced denitrification.

Main Methods:

• Quantitative polymerase chain reaction (q-PCR) to assess microbial abundance.
• High-throughput sequencing for microbial community analysis.
• Scanning electron microscopy (SEM) for visualizing microbial-particle interactions.

Main Results:

• Denitrification rates increased by 83.4% in synthetic and 11.1% in industrial wastewater with MGPs.
• MGPs significantly increased the abundance of denitrifying bacteria, particularly Paracoccus.
• The number of bacteria possessing the nirS gene, essential for denitrification, rose by 75.6%.

Conclusions:

• Micro-graphite particles effectively enhance denitrification in wastewater sludge.
• MGPs promote the growth of key denitrifying bacteria, improving nitrogen removal.
• This study presents the first evidence of MGP-mediated denitrification enhancement in industrial wastewater treatment.