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Updated: Sep 4, 2025
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Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
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Electrical voltage application as a novel approach for facilitating methanogenic granulation
Alsayed Mostafa1, Seongwon Im1, Young-Chae Song2
1Department of Smart-city Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea.
Bioresource Technology
|July 21, 2022
Summary
Applying electrical voltage (EV) significantly accelerates granulation in up-flow anaerobic sludge blanket reactors, reducing start-up times and enhancing performance under high organic loading rates. This method improves granule characteristics and microbial activity for efficient wastewater treatment.
Area of Science:
- Environmental Microbiology
- Wastewater Treatment Engineering
- Bioreactor Technology
Background:
- Up-flow anaerobic sludge blanket (UASB) reactors offer high-rate methanogenesis but suffer from prolonged granulation start-up periods (3-8 months).
- Accelerating granule formation is crucial for improving the efficiency and economic viability of UASB reactors.
Purpose of the Study:
- To investigate the efficacy of applying electrical voltage (EV) to facilitate and accelerate granulation in UASB reactors.
- To assess the impact of EV application on reactor performance, granule characteristics, and microbial community dynamics under increasing organic loading rates.
Main Methods:
- Continuous operation of UASB reactors with and without electrical voltage (0.3 V) application.
- Gradual increase of organic loading rates from 0.5 to 11.0 kg COD/m³/d.
- Analysis of granule properties (diameter, settling velocity, hydrophobicity), specific methanogenic activity, microbial community composition (Pseudomonas sp.), and quorum sensing (QS) gene expression.
Main Results:
- EV application enabled stable reactor performance up to 11.0 kg COD/m³/d, while the control reactor failed.
- Granules from the EV-treated reactor exhibited significantly larger diameter (2.3 vs 1.6 mm), higher settling velocity (2.6 vs 1.9 cm/s), and increased hydrophobicity (52.1% vs 34.5%) after 49 days.
- EV application approximately doubled the specific methanogenic activity for propionate and hydrogen.
- Relative abundance of Pseudomonas sp. increased by 17%, and QS gene expression rose by 27 times in the EV-treated reactor.
Conclusions:
- Electrical voltage application is a highly effective strategy for accelerating granulation in UASB reactors, significantly reducing start-up times.
- EV treatment enhances granule properties and microbial activity, leading to improved reactor stability and performance under high organic loads.
- The study highlights the role of quorum sensing mechanisms in EV-mediated granulation acceleration.
Keywords:
Direct interspecies electron transfer (DIET)Electrical voltageGranulationPhysico-chemical characteristicsQuorum sensingMore Related Videos
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