INTRINSIC KINETIC-PARAMETERS OF SUBSTRATE UTILIZATION BY ANAEROBIC SLUDGE ALONG THE HORIZONTAL-FLOW ANAEROBIC IMMOBILIZED SLUDGE (HAIS) REACTOR

This paper reports on experiments aiming at the estimation of kinetic parameters of substrate utilization by anaerobic sludge immobilized in polyurethane foam matrices at different positions along the horizonta l-flow anaerobic immobilized sludge (HAIS) reactor length. The methodo logy used is based on the minimization of mass transfer resistances by the establishment of adequate environmental and operational condition s. The experiments were carried out in an incubator shaker at 250 rpm. Each assay was performed utilizing substrate and bioparticles taken f rom five sampling ports along the HAIS reactor treating a glucose-base d synthetic substrate. Each assay lasted 12 hours and two flasks were taken every 3 hour for chemical oxygen demand (COD) analyses. The spec ific substrate utilization rates were obtained from the COD profiles o f substrate concentration in the bulk liquid along the experimental ti me and the intrinsic kinetic parameters were estimated considering Mon od type (r(max) and K-s) and first order (K-1) models. The intrinsic k inetic parameters estimated for each HAIS reactor segment ranged from 0.201 to 0.002 mg COD.mg(-1).VSS.h(-1) for r(max), from 1221 to 49 mg COD.l(-1) for K-s and from 8.94 x 10(-5) to 1.51 x 10(-5)l.mg(-1) VSS. h(-1) for K-1. Such a variation in intrinsic kinetic parameters was at tributed to changes in substrate and sludge composition along the reac tor length.