title: Characterization of a hydrogen-producing granular sludge.
abstract: This study demonstrated that hydrogen-producing acidogenic sludge could agglutinate into granules in a well-mixed reactor treating a synthetic sucrose-containing wastewater at 26 degrees C, pH 5.5, with 6 h of hydraulic retention. A typical matured granule is 1.6 mm in diameter, 1.038 g/mL in density, 11% in ash content, and over 50 m/h in settling velocity. Treating a solution containing 12.15 g/L of sucrose at a volumetric loading rate of 48.6 g/(L x d), the reactor containing 20 g/L of granular sludge degraded 97% of sucrose. Effluent comprised 46% acetate and 49% butyrate and the methane-free biogas comprised 63% hydrogen, 35% carbon dioxide, and 2% nitrogen. Hydrogen production rate was 13.0 L/(L x d), and the yield was 0.28 L/g-sucrose. The granule had multiple cracks on the surface and comprised two morphological types of bacteria: fusiform bacilli and a spore-forming bacterium. Phylogenetic analysis showed that 69.1% of the clones were affiliated with four Clostridium species in the family Clostridiaceae, and 13.5% with Sporolactobacillus racemicus in the Bacillus/Staphylococcus group.
authors.affiliation: Centre for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong. hrechef@hkucc.hku.hk
authors.forename: Herbert H P
authors.initials: HH
authors.lastname: Fang
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Tong
authors.initials: T
authors.lastname: Zhang
mesh_terms: D000438:Alcohols / Q000032:analysis; D019149:Bioreactors; D019976:Cloning, Organism; D003013:Clostridium / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D004275:DNA, Ribosomal / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D005740:Gases / Q000032:analysis; D006859:Hydrogen / Q000032:analysis* / Q000378:metabolism*; D007777:Lactobacillaceae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013395:Sucrose / Q000378:metabolism*; D014865:Waste Disposal, Fluid
chemical_list: D000438:Alcohols; D004275:DNA, Ribosomal; D005227:Fatty Acids; D005740:Gases; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D013395:Sucrose; D006859:Hydrogen