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A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
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Enhanced aerobic granulation, stabilization, and nitrification in a continuous-flow bioreactor by inoculating
Yang Yang1, Dandan Zhou, Zhengxue Xu
1Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun, 130021, China.
Applied Microbiology and Biotechnology
|March 20, 2014
Summary
Backwashed biofilm effectively seeds aerobic granular sludge reactors, reducing start-up time and enhancing wastewater treatment. This method improves chemical oxygen demand removal and nitrification, offering a stable alternative to activated sludge.
Area of Science:
- Environmental Microbiology
- Wastewater Engineering
- Bioreactor Technology
Background:
- Conventional aerobic granular sludge systems often rely on flocculent activated sludge for inoculation.
- Optimizing the start-up phase and granulation efficiency is crucial for effective wastewater treatment.
- Investigating alternative seeding materials can lead to improved bioreactor performance.
Purpose of the Study:
- To evaluate the efficacy of backwashed biofilm as an alternative seed material for aerobic granular sludge in a continuous-flow airlift fluidized bed (CAFB) reactor.
- To assess the impact of backwashed biofilm inoculation on reactor start-up time, granulation, and stability.
- To determine the efficiency of chemical oxygen demand (COD) removal and nitrification in the CAFB reactor.
Main Methods:
- Inoculation of a CAFB reactor with backwashed biofilm using municipal wastewater.
- Monitoring of reactor performance over a 90-day continuous operation period.
- Analysis of microbial distribution using fluorescence in situ hybridization (FISH).
- Microstructural examination of granules using scanning electron microscopy (SEM).
Main Results:
- Reactor start-up period was reduced to 25 days with enhanced aerobic granulation and stabilization.
- Achieved high COD removal efficiency (80-90%) and nitrification efficiency (60%) at steady state.
- Demonstrated significantly more stable performance compared to systems inoculated with activated sludge.
- FISH analysis revealed even distribution of ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) within granules.
- SEM showed broad holes in granules, facilitating nutrient mass transfer and simultaneous COD removal and nitrification.
Conclusions:
- Backwashed biofilm serves as a viable alternative seed for aerobic granular sludge systems.
- This method enhances both carbonaceous oxidation and nitrification processes in wastewater treatment.
- The unique microbial distribution and granule structure contribute to improved bioreactor efficiency and stability.
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