Effect of full and partial-bed configuration on carbon removal performance of biological aerated filters

Abstract

A comparative study to explore the characteristics of partially and fully packed biological aerated filters (BAFs) in the removal of carbon pollutant, reveals that the partial-bed reactor can perform comparably well with the full-bed reactor. The organic removal rate was 5.34 kg COD m(-3) d(-1) at Organic Loading Rates (OLR) 5.80+/-0.31 kg COD m(-3) d(-1) for the full-bed, and 5.22 kg COD m(-3) d(-1) at OLR 5.79+/-0.29 kg COD m(-3) d(-1) for the partial-bed. In the partial-bed system, where the masses of biomass were only 41-51% of those of the full-bed, the maximum carbon removal limit was still between 5 to 6 kg COD m(-3) d(-1). At organic loadings above 5.0 kg COD m(-3) d(-1), the carbon removal capacity in both systems was limited by the mass and activity of microorganisms. The SRT in the full and partial-bed reactors was primarily controlled by the biomass loss in the effluent and during backwash operation. The SRT was reduced from 20.08 days at OLR 4.18+/-0.20 kg COD m(-3) d(-1) to 7.62 days at OLR 5.80+/-0.31 kg COD m(-3) d(-1) in the full-bed, and from 7.17 days to 4.21 days in the partial-bed. After all, SRT values in the partial-bed were always lower than those in the full-bed.

Performance linked to residence time distribution by a novel wool-based bioreactor for tertiary sewage treatment

“…This is as expected; others have suggested (Jimenez et al 1988;Nabizadeh et al 2000;Tembhurkar and Mhaisalkar 2006;Kim and Bae 2007) that air bubbles create secondary circulations of the tracer thus making hydrodynamic patterns more uniform in bioreactors. Suja (2004) came to similar conclusions and reported gas and flow velocities from his investigations into optimum air flows for mixing in a biological aerated filter (BAF). A similar mixing effect is achieved in our moving bed SAFs from lower superficial gas velocities (0.04 m/h).…”