The Biological Aerated Filters (BAFs), permit to achieve high efficiency in the organic substance removal and in nitrification and de-nitrification processes. Furthermore, the packed bed filtering action can lead to the abatement of suspended solids, often making wastewater clarification an unnecessary process.In the present paper a new mathematical model is proposed, as result of an experimental investigation carried out on a bed biofilter reactor with small rigid PEad elements like filling support material, aerated at the bottom with compressed air forced through a porous ceramic membrane.This plant was feed with clarified wastewater, coming from the primary settling unit of an active sludge treatment plant, enriched with suitable dosage of sodium acetate, glycerine, (NH4)2SO4 e KH2PO4, in order to control organic and nitrogen loads and the ratio COD/N/P.The dependence of the organic matter removal rate on biomass surface density, on the dissolved oxygen concentration and on substrate biodegradability, was determined carrying out sequence kinetic tests on filling elements.The results of tests conducted with acetate suggest a zero order kinetic reaction with respect of rapidly biodegradable organic matter (RB), a first reaction rate with respect O2 concentration, while exhibit an asymptotic trend regarding the biomass surface density.The kinetic tests carried out with glycerine and starch suggest a zero order kinetic reaction respect rapidly hydrolysable (RH) and slowly biodegradable (SB) substrate concentration, while in respect of dissolved oxygen concentration, showed a ½ order reaction and an asymptotic trend respectively for RH and SB removal.On the basis of these results it was possible to define a mathematical model, that can simply the bioreactors design, predicting the removal ability of submerged biofilter reactors, as related to their volume, to the specific surface of the filling elements, to the applied organic load, to biodegradability of influent wastewater, to oxygen concentration and to operating temperature.Its validity has been confirmed by the substantial coincidence of the values of the removed organic loads as monitored on the experimental apparatus and the corresponding model predictions.
Formulation of a new model describing the organic matter removal in biofilter reactors
SICILIANO, Alessio
2009-01-01
Abstract
The Biological Aerated Filters (BAFs), permit to achieve high efficiency in the organic substance removal and in nitrification and de-nitrification processes. Furthermore, the packed bed filtering action can lead to the abatement of suspended solids, often making wastewater clarification an unnecessary process.In the present paper a new mathematical model is proposed, as result of an experimental investigation carried out on a bed biofilter reactor with small rigid PEad elements like filling support material, aerated at the bottom with compressed air forced through a porous ceramic membrane.This plant was feed with clarified wastewater, coming from the primary settling unit of an active sludge treatment plant, enriched with suitable dosage of sodium acetate, glycerine, (NH4)2SO4 e KH2PO4, in order to control organic and nitrogen loads and the ratio COD/N/P.The dependence of the organic matter removal rate on biomass surface density, on the dissolved oxygen concentration and on substrate biodegradability, was determined carrying out sequence kinetic tests on filling elements.The results of tests conducted with acetate suggest a zero order kinetic reaction with respect of rapidly biodegradable organic matter (RB), a first reaction rate with respect O2 concentration, while exhibit an asymptotic trend regarding the biomass surface density.The kinetic tests carried out with glycerine and starch suggest a zero order kinetic reaction respect rapidly hydrolysable (RH) and slowly biodegradable (SB) substrate concentration, while in respect of dissolved oxygen concentration, showed a ½ order reaction and an asymptotic trend respectively for RH and SB removal.On the basis of these results it was possible to define a mathematical model, that can simply the bioreactors design, predicting the removal ability of submerged biofilter reactors, as related to their volume, to the specific surface of the filling elements, to the applied organic load, to biodegradability of influent wastewater, to oxygen concentration and to operating temperature.Its validity has been confirmed by the substantial coincidence of the values of the removed organic loads as monitored on the experimental apparatus and the corresponding model predictions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
