EVALUATION OF REVERSIBLE FIXED-FILM STATIC-BED BIO-DENITRIFICATION REACTORS

This paper reports the results of a study to investigate the performan ce of fixed-film two-stage reversible biodenitrification reactors oper ated at very short detention limes for the removal of nitrates from co ntaminated groundwater. The results demonstrate that these systems imp arted lower concentrations of organics and suspended solids into the t reated effluent than traditional single-stage systems while maintainin g higher levels of nitrate removal rates at HRT values as low as 30 mi nutes. The lower detention times translate into substantial reductions in capital cost on scaled-up systems. The results also demonstrate th e ability of two-stage reversible flow systems to withstand the stress es associated with low HRT and flow cycle reversals. (C) 1998 Publishe d by Elsevier Science Ltd. All rights reserved