ANOMALIES IN THE TRANSFORMATION OF 3-CHLOROBENZOATE IN PERCOLATION COLUMNS WITH PSEUDOMONAS SP. STRAIN B13

The biotransformation of 3-chlorobenzoate (3CB) by attached cells of P seudomonas sp. strain B13 was studied in percolation columns operated at various flow rates and biomass contents. Steady-state residual effl uent concentrations were compared with predictions from spreadsheet mo dels describing the combined action of microbial and mass transfer kin etics. The effluent concentrations were successfully predicted above a critical ratio of flow rate and biomass. Below this critical point th e steady-state residual effluent concentrations were higher than predi cted and this deviation increased with decreasing flow rate:biomass ra tios. The results are discussed in the light of convection-diffusion p rocesses limiting the transport of both substrate and oxygen to the at tached cells. (C) 1998 IAWQ. Published by Elsevier Science Ltd.