TABLE 3.

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

Date (mo/day/yr)ProcessOrganism(s)Concn (CFU · ml−1)
6/20/2000Rapid sand filtrationM. peregrinum>20,000
M. gordonae>6,000
Ozone treatmentNDa
GAC filtrationUnidentified mycobacteriab20
Treated water (chlorination)Unidentified mycobacteria20
9/19/2000Rapid sand filtrationUnidentified mycobacteria20
M. gordonae3,000
M. gordonae400
Ozone treatmentND
GAC filtrationUnidentified mycobacteriab20
Unidentified mycobacteriab10
Treated water (chlorination)ND
12/19/2000Rapid sand filtrationUnidentified mycobacteria3,000
Ozone treatmentND
GAC filtrationUnidentified mycobacteriab10
Treated water (chlorination)Unidentified mycobacteriab10
3/20/2001Rapid sand filtrationM. gordonae500
Ozone treatmentND
GAC filtrationUnidentified mycobacteriab10
Treated water (chlorination)ND
6/19/2001Rapid sand filtrationM. gordonae100
Ozone treatmentM. gordonae10
GAC filtrationUnidentified mycobacteriab20
Treated water (chlorination)ND
  • a ND, not detected.

  • b Identical mycobacteria.