Removal of monochlorobenzene from air in a trickling biofilter at high loading rates |
| |
| Authors: | Mario Zilli Cristiano Nicolella |
| |
| Affiliation: | 1. Department of Chemical and Process Engineering “G.B. Bonino”, University of Genoa, Via Opera Pia 15, 16145, Genoa, Italy;2. Department of Chemical Engineering, University of Pisa, Via Diotisalvi 2, 56126, Pisa, Italy |
| |
| Abstract: | BACKGROUND: In this study, the biofiltration of air streams laden with monochlorobenzene (MCB) vapours was investigated using a trickling biofilter operated co‐currently. The device was filled with ceramic material and inoculated with an acclimated microbial culture. A neutralization process was carried out in a separate unit using crushed oyster shells. Long‐term biofilter performance was evaluated over a 10‐month period of continuous experiments under different influent pollutant concentrations from 0.10 to 1.75 g m?3, sequentially stepped up through three different apparent air residence times of 60, 30, and 15 s. RESULTS: Pollutant removal was shown to be complete at influent concentrations up to 1.25, 0.75 and 0.20 g m?3, and apparent air residence times of 60, 30, and 15 s, respectively. The maximum elimination capacity was found to be 95.0 g mPM?3 h?1 for an influent concentration of 1.0 g m?3 and an apparent air residence time of 30 s, corresponding to a loading rate of 120.0 g mPM?3 h?1. Monochlorobenzene and biomass concentration profiles along the biofilter evidenced the dependence of microbial concentration distribution on the pollutant loading rate and the existence of a linear relationship between biomass concentration and specific pollutant removal rate, regardless of the operating conditions applied. A macrokinetic analysis shows that the MCB removal rate is zeroth order for low values of MCB concentration. A critical value of MCB concentration exists at all superficial air velocity at which the biomass growth is inhibited. A simple kinetic model is developed which is able to describe the inhibition behaviour under any operating conditions. CONCLUSION: The experimental results indicated that the system was effective and stable under various working conditions and over a long operating period, provided that the loading conditions corresponding to substrate inhibition of microbial growth are not exceeded. Copyright © 2012 Society of Chemical Industry |
| |
| Keywords: | monochlorobenzene trickling biofilter crushed oyster shells microbial concentration distribution long‐term performance macrokinetics |
|
|
