AWWA ACE56264

The validity of a macroscopic model to accurately predict the filtration cycle from ripening to breakthrough was investigated. A laboratory scale filter column containing soda lime silica glass beads was used to filter a latex particle suspension, and the data collected was used in the modeling program. Further, the study also endeavored to determine the significance of hydrophobic and hydrophilic forces in filtration theory. The variables in the investigation were: influent particle concentration (4.5 *10[5] particles/ml and 1.35 * 10[6] particles/ml), filter media depth (5 cm and 15 cm), filtration rate (5 m/hr and 10 m/hr), and particle type (hydrophobic and hydrophilic). A macroscopic model was tested, through simulation and calibration. Simulation of the influence of the different parameters on the removal and headloss curves showed the interdependence of the different parameters. The detachment term and its link to headloss development added complexity to use of the model. The shape of the breakthrough stage was mainly determined by the detachment parameter and the headloss curve. The calibration process for the model was very sensitive to the initial parameter guesses and to the balance desired between particle removal and fitting of headloss curves. The model could be fitted to laboratory scale experiments, in well-defined conditions and with an influent close to monodispersed particles, and exhibiting only the ripening and working stage of filtration. The research is ongoing. Includes 13 references, figures.