Premium
Mass‐transport dynamics, activity, and structure of sulfate‐reducing biofilms
Author(s) -
Beyenal Haluk,
Lewandowski Zbigniew
Publication year - 2001
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690470721
Subject(s) - biofilm , chemistry , thermal diffusivity , sulfide , desulfovibrio , sulfate reducing bacteria , pseudomonas fluorescens , sulfate , flow velocity , flux (metallurgy) , analytical chemistry (journal) , chemical engineering , bacteria , flow (mathematics) , environmental chemistry , thermodynamics , mechanics , geology , physics , organic chemistry , engineering , paleontology
Factors limiting hydrogen sulfide production were identified in a two‐species biofilm containing sulfate‐reducing bacteria (Desulfovibrio desulfuricans) and nonsulfate‐reducing bacteria (Pseudomonas fluorescens). Profiles of hydrogen sulfide (H 2 S) concentration, pH, local mass‐transport coefficient, local flow velocity, and local relative effective diffusivity in the biofilm were measured using microelectrodes. Biofilms had a heterogeneous structure consisting of cell clusters separated by voids. Typically, the H 2 S concentration was lower in the voids than in the adjacent cell clusters, demonstrating that the voids acted as transport channels for removing H 2 S from cell clusters. The extent of biofilm heterogeneity was directly correlated with the flux of H 2 S from cell clusters. At flow velocities below 2 cm/s, the flux of H 2 S from cell clusters depended on the flow velocity. We concluded that at these flow velocities the H 2 S production rate was limited by the delivery rate of sulfate ions to the biofilm. At flow velocities above 2 cm/s, the H 2 S production rate was nearly constant and did not depend on the flow velocity. At high flow velocities (>2 cm/s) the H 2 S production rate was limited by metabolic reactions in the biofilm. Local intrabiofilm flow velocity profiles were influenced strongly by biofilm heterogeneity without significant pH variation within biofilms. Surprisingly, profiles of local relative effective diffusivity indicated that the biofilm was made up of two layers, which could be related to the specimen with a two‐species biofilm.