Transport of Escherichia coli strains isolated from springs in Kampala, Uganda - Transport of Multiple Escherichia Coli Transport in Saturated Porous Media - page 106

and highest attaching bacteria strains, respectively, we observed that 75 % of the strains had
Αvalues in the order of 10 -3 and 10 -4 .

In order to compare the importance of equilibrium sorption with kinetic attachment, we
determined the total bacteria mass fraction involved in both types of interactions with the
quartz grains. The total bacteria mass fraction involved in equilibrium sorption was
determined by making use of equation (4). The total bacteria mass fraction involved in
kinetic attachment was determined from the measured difference between total bacteria mass
input and total bacteria mass output. The results suggested two groups of bacteria strains
( Fig.7. 5 ) :

1. A group of strains with approximately equivalent (low) mass fractions involved in
both equilibrium sorption and kinetic attachment (group I), and
2. A group of strains with a high fraction of their cells involved in kinetic attachment,
while the fraction of cells involved in equilibrium sorption was low and comparable
to the group I strains (group II).

1.0

0.8

Group I
Group II

0.6

0.4

0.2

0.0

0.0 0.2 0.4 0.6 0.8 1.0

Equilibrium E. coli mass (% of input mass)

Fig. 7.5: Relation between fraction of cells with kinetic and equilibrium transport

characteristics, indicating two groups:Group I-strains with equivalent (low)
mass fractions involved in both equilibrium sorption and kinetic attachment
and group II-strains with high fraction of cells involved in kinetic attachment

Most of the strains (33 out of 40, or 82%) belonged to group I. Their breakthrough were
somewhat retarded, while their maximum relative breakthrough concentrations were above
0.5; their sticking efficiency values were usually between 10 -3 and 10 -4 . The group II strains