Mass transfer improvement of a fixed-bed anaerobic sequencing batch reactor with liquid-phase circulation

An anaerobic sequencing batch reactor (ASBR) containing biomass immobilized in polyurethane foam was used to treat low strength wastewater. The reactor was operated with liquid-phase external circulation in order to minimize the mass transfer limitations, typical of systems containing immobilized biomass. The reactor was operated at 30ºC and an 8-hour cycle was used to treat a synthetic wastewater with chemical oxygen demand (COD) of 500mg/L. The system achieved overall substrate removal efficiency of 72% with no circulation and 87% when circulation was implemented, i.e., the reactor performance increased as mixing was implemented. Furthermore, a first-order kinetic model with residual substrate concentration was fitted to the experimental values to evaluate the influence of liquid circulation on the reactor performance during a cycle time. The apparent first-order parameter was seen to increase (from 1.19 to 2.00h-1) with increasing superficial velocity (from 0.032 to 0.191cm/s) up to a stable value (1.90h-1) for higher values of superficial velocity (from 0.191 to 0.467cm/s).

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Bibliographic Details
Main Authors: Ramos,Ana C.T., Ratusznei,Suzana M., Rodrigues,José A.D., Zaiat,Marcelo
Format: Digital revista
Language:English
Published: ASOCIACIÓN INTERCIENCIA 2003
Online Access:http://ve.scielo.org/scielo.php?script=sci_arttext&pid=S0378-18442003000400006
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