Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | MEMBRANE BIOREACTOR SLUDGE RHEOLOGY AT DIFFERENT SOLID RETENTION TIMES |
| Abstract | Rheological characterization is of crucial importance in sludge management both in terms of biomass dewatering and stabilization properties and in terms of design parameters for sludge handling operations. The sludge retention time (SRT) has a significant influence on biomass properties in biological wastewater treatment systems and in particular in membrane bioreactors (MBRs). The aim of this work is to compare the rheological behaviour of the biomass in a MBR operated under different SRTs. A bench-scale MBR was operated for 4 years under the same conditions except for the SRT, which ranged from 20 days to complete sludge retention. The rheological properties were measured over time and the apparent viscosity was correlated with the concentration of solid material when equilibrium conditions were reached and maintained. The three models most commonly adopted for rheological simulations were evaluated and compared in terms of their parameters. Then, steady-state average values of these parameters were related to the equilibrium biomass concentration (MLSS). The models were tested to select the one better fitting the experimental data in terms of mean root square error (MRSE). The relationship between the apparent viscosity and the shear rate, as a function of solid concentration, was determined and is proposed here. Statistical analysis showed that, in general, the Bingham model provided slightly better results than the Ostwald one. However, considering that a strong correlation between the two parameters of the Ostwald model was found for all the SRTs tested, both in the transient growth phases and under steady-state conditions, this model might be used more conveniently. This feature suggests that the latter model is easier to be used for the determination of the sludge apparent viscosity. |
| Source | Water research (Oxf.) 41 (18), pp. 4197–4203 |
| Journal | Water research (Oxf.) |
| Editor | Pergamon Press., New York, Regno Unito |
| Year | 2007 |
| Type | Articolo in rivista |
| DOI | 10.1016/j.watres.2007.05.032 |
| Authors | LAERA G., GIORDANO C., POLLICE A., SATURNO D., MININNI G. |
| Text | 42202 2007 10.1016/j.watres.2007.05.032 ISI Web of Science WOS 000250247800018 MEMBRANE BIOREACTOR SLUDGE RHEOLOGY AT DIFFERENT SOLID RETENTION TIMES LAERA G., GIORDANO C., POLLICE A., SATURNO D., MININNI G. Istituto di Ricerca Sulle Acque CNR, Via F. De Blasio 5, 70123 Bari, Italy Istituto di Ricerca Sulle Acque CNR, Via Reno 1, 00198 Roma, Italy Rheological characterization is of crucial importance in sludge management both in terms of biomass dewatering and stabilization properties and in terms of design parameters for sludge handling operations. The sludge retention time SRT has a significant influence on biomass properties in biological wastewater treatment systems and in particular in membrane bioreactors MBRs . The aim of this work is to compare the rheological behaviour of the biomass in a MBR operated under different SRTs. A bench scale MBR was operated for 4 years under the same conditions except for the SRT, which ranged from 20 days to complete sludge retention. The rheological properties were measured over time and the apparent viscosity was correlated with the concentration of solid material when equilibrium conditions were reached and maintained. The three models most commonly adopted for rheological simulations were evaluated and compared in terms of their parameters. Then, steady state average values of these parameters were related to the equilibrium biomass concentration MLSS . The models were tested to select the one better fitting the experimental data in terms of mean root square error MRSE . The relationship between the apparent viscosity and the shear rate, as a function of solid concentration, was determined and is proposed here. Statistical analysis showed that, in general, the Bingham model provided slightly better results than the Ostwald one. However, considering that a strong correlation between the two parameters of the Ostwald model was found for all the SRTs tested, both in the transient growth phases and under steady state conditions, this model might be used more conveniently. This feature suggests that the latter model is easier to be used for the determination of the sludge apparent viscosity. 41 http //www.sciencedirect.com/science/article/pii/S0043135407003375 Articolo pubblicato 2007_Wat_Res_41_4197_4203.pdf Articolo in rivista Pergamon Press. 0043 1354 Water research Oxf. Water research Oxf. Water res. Oxf. Water research. Oxf. alfieri.pollice POLLICE ALFIERI giuseppe.laera LAERA GIUSEPPE giuseppe.mininni MININNI GIUSEPPE TA.P07.001.003 Processi innovativi per il trattamento e lo smaltimento dei fanghi di depurazione TA.P07.002.004 Processi biotecnologici e processi a membrana |