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Characterization of a hydrogen-producing granular sludge.
Herbert H P Fang1, Hong Liu, Tong Zhang
1Centre for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong. hrechef@hkucc.hku.hk
Biotechnology and Bioengineering
|February 22, 2002
Summary
Hydrogen-producing acidogenic sludge formed granules in a reactor, efficiently degrading sucrose and producing hydrogen gas. These granules exhibited excellent settling properties and were composed of specific bacterial types.
Area of Science:
- Microbiology
- Environmental Engineering
- Biotechnology
Background:
- Acidogenic sludge is crucial for wastewater treatment and biogas production.
- Granulation of sludge can enhance treatment efficiency and settleability.
- Hydrogen production from organic waste is a sustainable energy goal.
Purpose of the Study:
- To investigate the granulation of hydrogen-producing acidogenic sludge.
- To characterize the properties of the formed granules.
- To evaluate the efficiency of sucrose degradation and hydrogen production by the granular sludge.
Main Methods:
- Cultivation of granular sludge in a well-mixed reactor under specific conditions (26°C, pH 5.5, 6h HRT).
- Characterization of granule properties (size, density, ash content, settling velocity).
- Analysis of effluent composition, biogas content, and hydrogen yield.
- Microscopic observation and phylogenetic analysis of bacterial communities within the granules.
Main Results:
- Granular sludge formation was achieved, with mature granules measuring 1.6 mm in diameter and exhibiting high settling velocity (>50 m/h).
- The reactor achieved 97% sucrose degradation, producing methane-free biogas rich in hydrogen (63%).
- Hydrogen production rate was 13.0 L/(L x d) with a yield of 0.28 L/g-sucrose.
- Granules comprised fusiform bacilli and spore-forming bacteria, with dominant Clostridium species and Sporolactobacillus racemicus.
Conclusions:
- Hydrogen-producing acidogenic sludge can effectively form granules in a well-mixed reactor.
- The developed granular sludge demonstrates high efficiency in sucrose degradation and hydrogen production.
- The microbial community, dominated by Clostridium and Sporolactobacillus, plays a key role in granulation and hydrogenesis.