The goal of this research was to increase the understanding of the filtration mechanisms and to
also further the efforts of improved modeling of the filtration process. The macroscopic model
used in this research included the detachment mechanism and thus, it was able to model the
entire cycle of filtration. An assessment of the ability of the model to predict the filtration
process for varying types of particles, mainly hydrophobic and hydrophilic particles, was an
important aspect of this research. This is one of the first efforts to determine the importance of
particle hydrophobicity and hydrophilicity on particle removal in deep bed filtration. To this
point, past research efforts have suggested that this difference may be significant; however, no
detailed research into this area has been conducted.
In order to alleviate the difficulty in having to determine model parameter values through
experimental data, empirical equations for the direct calculation of the ripening, detachment,
and headloss parameters were determined. Literature and prior research has indicated that
values of the three parameters are affected by filtration rate, filter media depth, diameter of the
media grains, and diameter of the influent particles. Since the experiments conducted as part of
this research incorporates a wide array of filtration conditions, it was possible to derive
empirical equations for the three parameters. Previously determined empirical equations all
contain different combinations of the following filter operating variables: filtration rate, influent
concentration, particle diameter, and filter media diameter. However, none of the equations
contain all the filtration variables. Furthermore, the depth of the filter media is not considered
in any of the empirical relationships previously established. Therefore, more detailed equations
are needed to account for all the variables involved and thus, to accurately calculate the model
parameters. The empirical equations derived as part of this research were able to accurately
predict the parameter values generated by the model through the simultaneous fit of the
experimental removal and headloss data. The empirical equations were most accurate for the
ripening and headloss model parameters. The equation derived for the detachment parameter
was less precise than the equations for the other two parameters.
Another aspect of this investigation involved how the knowledge of the difference in
removal efficiency and headloss development for hydrophilic particles impact practical
filtration and filtration modeling. To answer that question, Suwannee River natural organic
matter was added to the influent water containing hydrophobic particles, and a series of
experiments were conducted in the exact fashion as the previous eight experiments using
hydrophobic latex particles. The effluent and headloss data generated through these new
experiments with the hydrophobic particle and Suwannee River natural organic matter mixture
was then compared to the data produced by the experiments using hydrophilic particles and
hydrophobic particles. After making this comparison, it was noted that in all the experiments
conducted with hydrophobic particles and Suwannee River natural organic matter the removal
and headloss curves closely modeled the curves generated for the same experimental conditions
but with hydrophilic particles. Therefore, knowledge of particle hydrophilicity and
hydrophobicity is important in understanding the removal of natural organic matter during
filtration.
Includes 21 references, table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 370 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 13 |
| Published : | 06/17/2004 |
