Transport of Escherichia coli in 25 m columns - Transport of Multiple Escherichia Coli Transport in Saturated Porous Media - page 64

Fig. 5.1: Set up of the helical column
5.2.2 Bacteria growth and column experiments
Two Escherichia coli ( E. coli ) strains (UCFL-94 and UCFL-131) were selected for their low
sticking efficiency, based on the work of Foppen et al. (2010). The strains had originally been
obtained from the soil of a pasture used for cattle grazing (Yang et al., 2004). To grow bacteria,
the isolates were activated from a peptone agar stock in Luria Bertani Broth (DifcoTM LB Broth,
Miller) for 6 hours at 37 °C, while shaking at 150 rpm on an orbital shaker. Then, 5 mL of the of
the bacteria suspension was diluted in 250 mL of Nutrient Broth and incubated while shaking on
the orbital shaker for 24 hours at 37 °C to reach a stationary growth phase at a concentration of
~10 9 cells/ml.
To study the distributions of sticking efficiencies and to measure very low sticking efficiency
values of the E. coli strains, bacteria transport experiments were conducted using artificial
groundwater (AGW). AGW was prepared by dissolving 526 mg/L CaCl 2 .2H 2 O and 184 mg/L
MgSO 4 .7H 2 O in DI water, and buffered it with 8.5 mg/L KH 2 PO 4 , 21.75 mg/L K 2 HPO 4 and 17.7
mg/L Na 2 HPO 4 . The resultant pH-value ranged between 6.6 and 6.8 and the Electrical
Conductivity (EC)-value ranged from 1025 to 1054 S/cm. Prior to a bacteria transport