Article ID Journal Published Year Pages File Type
4485495 Water Research 2009 10 Pages PDF
Abstract

A multi-compartment anaerobic bioreactor, designated the anaerobic migrating blanket reactor (AMBR), did not perform well in terms of chemical oxygen demand (COD) removal after an increase in sulfate load, compared to a conventional upflow anaerobic sludge blanket (UASB) reactor. The trophic structures of the bioreactors were characterized by analyzing the electron flows, formation and consumption of fermentation intermediates and terminal product (methane and hydrogen sulfide) formation. Critical performance parameters were linked to operational perturbations such as increase in sulfate load and changes in flow reversal schemes in the AMBR. Both of these manipulations affected the microbial communities, which were monitored by terminal restriction fragment length polymorphism (T-RFLP) analysis targeting the bacterial and archaeal domains. The less stable AMBR did not produce granular biomass, and in response to increased sulfate concentrations, experienced a reversal in the distribution of hydrogenotrophic methanogens that correlated with a shift in electron flow from butyrate to propionate. As this shift occurred, bacterial populations such as butyrate-producing clostridia, became predominant, thus leading to reactor imbalance. The stable UASB reactor developed and retained granules and maintained a relatively stable archaeal community. Sulfate perturbation led to the selection of a novel bacterial group (Thermotogaceae), which was most likely well adapted to the increasingly sulfidogenic conditions in the bioreactor.

Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Earth-Surface Processes
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