TABLE 4.

Concentrations of mycobacteria isolated from the water from the Ivry treatment plant at some intermediate stages of treatment, in which slow sand filtration is used

Date (mo/day/yr)ProcessOrganism(s)Concn (CFU · liter−1)
3/28/2000PrefiltrationNDa
Slow sand filtrationND
Ozone treatmentND
GAC filtrationM. peregrinum>3,000
Treated water (chlorination)ND
7/18/2000PrefiltrationContaminated
Slow sand filtrationUnidentified mycobacteria10
Ozone treatmentM. nonchromogenicum10
GAC filtrationM. fortuitum>>3,000
Treated water (chlorination)ND
10/17/2000PrefiltrationM. nonchromogenicum100
Slow sand filtrationM. peregrinum800
M. flavescens10
M. chelonae10
Ozone treatmentND
GAC filtrationM. fortuitum-M. peregrinum2,000
Treated water (chlorination)ND
1/23/2001PrefiltrationM. duvalii20
Unidentified mycobacteria300
Unidentified mycobacteria2,000
M. flavescens20
Slow sand filtrationM. peregrinum>400
Ozone treatmentND
GAC filtrationM. peregrinum>3,000
Treated water (chlorination)M. nonchromogenicum60
4/17/2001PrefiltrationContaminated
Slow sand filtrationUnidentified mycobacteria10
Ozone treatmentND
GAC filtrationM. peregrinum1,500
Treated water (chlorination)ND
7/17/2001PrefiltrationContaminated
Slow sand filtrationContaminated
Ozone treatmentND
GAC filtrationM. fortuitum2,000
Unidentified mycobacteria10
Treated water (chlorination)ND
  • a ND, not detected.