All biofiltration steps analyzed in this study (biological wastewater treatment, rapid sand filtration, granular activated carbon filtration, and slow sand filtration)reduced AOC concentrations and the growth potential of E. coli O157 and P. aeruginosa.
The PGP assay can, therefore,be used to evaluate, optimize, and compare different biofilter systems.
Interestingly, V. cholerae often responded uniquely in samples collected after oxidation steps.
It appears that during oxidation the quality of carbonaceous compounds in the water
is altered in such a way that the potential risk for growth of this pathogen is in fact reduced, although the concentration of AOC increases (Fig. 2, 3, and 5).