Enhanced quinoline removal by zero-valent iron-coupled novel anaerobic processes: performance and underlying function...

Area of Science:

• Environmental Science
• Environmental Chemistry
• Microbiology

Background:

• Quinoline poses ecological risks due to its toxicity and resistance to biodegradation.
• Effective methods are needed to mitigate quinoline contamination in ecosystems.

Purpose of the Study:

• To investigate the efficacy of zero-valent iron (ZVI) in enhancing quinoline degradation within an anaerobic digestion (AD) system.
• To compare the performance of different ZVI types (iron powder, iron scrap, rusty iron scrap) on pollutant removal and biogas production.

Main Methods:

• Batch experiments were conducted to assess ZVI's impact on quinoline degradation, methane production, volatile fatty acids (VFAs), and chemical oxygen demand (COD) removal.
• High-throughput sequencing was used to analyze microbial community structure and function.

Main Results:

• ZVI addition significantly improved quinoline and COD removal, methane production, and acetic acid formation compared to AD alone.
• Rusty iron scrap demonstrated the highest efficiency, increasing quinoline and COD removal by 28.6% and 19.9%, respectively.
• ZVI addition led to increased ferrous ion accumulation and pH self-buffering, enhancing microbial activity and enriching quinoline-degrading bacteria like *Pseudomonas* and *Bacillus*.

Conclusions:

• ZVI, particularly rusty iron scrap, is a promising additive for enhancing anaerobic digestion performance in treating quinoline-contaminated environments.
• The integration of ZVI into AD systems positively impacts microbial community structure and function, promoting the degradation of recalcitrant pollutants.