China 
Africa 
Explore chapters and articles related to this topic
Efficiencies of Substrates, Vegetation, Water Levels and Microbial Populations
Published in Donald A. Hammer, Constructed Wetlands for Wastewater Treatment, 2020
Dissimilatory sulfate reduction is a microbial process that commonly occurs in anoxic aquatic environments. By-products of the process are hydrogen sulfide and carbonate alkalinity. Sulfate reduction in wetlands constructed to treat acid mine drainage (AMD) is desirable because hydrogen sulfide readily reacts with dissolved metals, precipitating them as sulfides, and alkalinity neutralizes drainage acidity. This chapter discusses factors which affect the importance of sulfide formation in aquatic systems and evaluates the theoretical potential of the process in wetlands constructed to treat AMD. The importance of dissimilatory sulfate reduction (DSR) in affecting the chemistry of flow-through water is related to the difference between rates of formation and destruction of sulfides. The plan calls for the acid inflow to be partially neutralized by the limestone, subjected to DSR processes as it diffuses upward through the organic substrate, and subjected to oxidizing, “polishing” processes at the wetland surface.
Microbiological Aspects
Published in Héctor A. Videla, Manual of Biocorrosion, 2018
The sulfur cycle is also formed by two types of microorganisms able to reduce sulfate: (1) when sulfate is used as the sulfur source for its reduction to organic sulfides through a metabolic process called assimilatory sulfate reduction and (2) when the sulfate is used as the terminal electron acceptor in the anaerobic respiration, producing hydrogen sulfide through the dissimilatory sulfate reduction. One of the members of this group of microorganisms is the well known corrosion-causing SRB, Desulfovibrio desulfuricans. This is an obligate anaerobe and heterotroph using low molecular weight carbon compounds (e.g., lactate, acetate, propionate) as external carbon sources.
Characterizing phenol-removing consortia under methanogenic and sulfate-reducing conditions: potential metabolic pathways
Published in Environmental Technology, 2019
Leandro Augusto Gouvêa de Godoi, Lucas Tadeu Fuess, Tiago Palladino Delforno, Eugenio Foresti, Marcia Helena Rissato Zamariolli Damianovic
The microbial composition of the two reactors treating CRSW under strictly methanogenic (R1) and simultaneous methanogenic/sulfidogenic conditions (R2) was analyzed by Illumina MiSeq sequencing. The number of sequences generated were 237,345 (R1) and 244,283 (R2), grouped into 1188 and 1036 OTUs for R1 and R2 samples, respectively. The sequences obtained were compared with the microbial composition of the inoculum (235,800 sequences grouped into 841 OTUs), previously reported [51]. The characterization of the microbial structure of the reactors at the genus level is depicted in Figure 3a-c. The extended error bar plots (Figure 3) show the statistically significant differences in the taxonomic profiles of the biomass from the two reactors and the inoculum. Relative abundance values indicated the predominance of the Desulfonauticus genus (9.3%; Figure 3a) in R2, suggesting that this particular genus was the primary microbial group conducting the dissimilatory sulfate reduction in this system. Species belonging to Desulfonauticus genus, such as D. submarinus, use hydrogen as an electron donor in the reduction of sulfate, sulfite, thiosulfate or elemental sulfur [52]. Organisms belonging to the Thermanaerovibrio genus (8.3%; Figure 3a) were also identified in R2, and were characterized by their ability to convert several organic substrates into hydrogen. The growth of this particular group is enhanced in the co-cultivation with hydrogen scavengers [53], such as SRB.