TABLE 1.
Concentrations of influent and 30-min-effluent microorganisms for POU disinfectant systems treating sewage-contaminated water
| Microorganism group | Geometric mean concn (range) [% of samples below detection limit]a |
|||||||
|---|---|---|---|---|---|---|---|---|
| NaDCC |
Flocculant-disinfectant |
Cl-contact |
Br-contact |
|||||
| Influent | Effluent at 30 min | Influent | Effluent at 30 min | Influent | Effluent at 30 min | Influent | Effluent at 30 min | |
| Total coliforms | 2.7 × 104 (6.7 × 103 to 7.6 × 104) | 4.3 (4.0 × 10−2 to 1.6 × 102) | 1.7 × 104 (1.2 × 104 to 2.7 × 104) | 4.0 × 10−2 (<1.0 × 10−2 to 2.4 × 10−1) [33] | 2.9 × 104 (2.3 × 104 to 4.0 × 104) | <1.0 × 10−2 [100] | 4.5 × 104 (1.9 × 104 to 7.2 × 104) | 1.1 × 10−2 (<1.0 × 10−2 to 1.3 × 10−2) [66] |
| Heterotrophic plate counts | 8.7 × 104 (2.7 × 104 to 1.8 × 105) | 6.4 × 101 (2.1 × 101 to 4.5 × 102) | 8.9 × 104 (2.9 × 104 to 4.3 × 105) | 8.5 (4.7 to 2.7 × 101) | 6.6 × 104 (3.5 × 104 to 1.1 × 105) | 3.9 (3.5 to 4.2) | 8.3 × 104 (2.4 × 104 to 2.0 × 105) | 4.6 (2.2 to 7.7) |
| E. coli | 3.3 × 103 (7.7 × 102 to 1.1 × 104) | 1.8 × 101 (9.0 × 10−1 to 5.3 × 102) | 6.7 × 103 (2.3 × 103 to 4.3 × 104) | 1.1 × 10−2 (<1.0 × 10−2 to 1.3 × 10−2) [66] | 4.7 × 103 (2.3 × 103 to 1.1 × 104) | <1.0 × 10−2 [100] | 1.5 × 104 (6.3 × 103 to 4.6 × 104) | <1.0 × 10−2 [100] |
| Enterococci | 8.8 × 102 (5.7 × 102 to 1.3 × 103) | 2.3 (<1.0 × 10−2 to 4.9 × 101) [33] | 6.3 × 102 (5.0 × 102 to 8.7 × 102) | <1.0 × 10−2 [100] | 9.9 × 102 (5.3 × 102 to 1.7 × 103) | <1.0 × 10−2 [100] | 1.3 × 103 (7.3 × 102 to 2.3 × 103) | <1.0 × 10−2 [100] |
| Clostridia | 1.6 × 102 (6.0 × 101 to 3.0 × 102) | 6.4 (6.7 × 10−1 to 7.7 × 101) | 2.0 × 102 (7.0 × 101 to 6.0 × 102) | 7.9 × 10−1 (4.5 × 10−1 to 1.4) | 3.4 × 101 (2.0 × 101 to 6.3 × 101) | 2.4 × 10−2 (<1.0 × 10−2 to 6.0 × 10−2) [33] | 4.4 × 101 (2.7 × 101 to 9.3 × 101) | 7.4 × 10−2 (<1.0 × 10−2 to 3.6 × 10−1) [33] |
| Coliphage | 1.5 × 102 (1.2 × 102 to 2.2 × 102) | 3.1 × 101 (<1.0 to 1.8 × 102) [33] | 1.4 × 102 (1.3 × 102 to 1.4 × 102) | 1.9 × 101 (<1.0 to 1.1 × 102) [33] | 9.4 × 101 (4.3 × 101 to 1.6 × 102) | 7.3 (1.3 to 4.7 × 101) | 7.7 × 101 (4.0 × 101 to 1.2 × 102) | <1.0 [100] |
a
Values shown are numbers of CFU/ml except those for coliphage, which are numbers of PFU/ml. The percentage of samples below the detection limit (n = 3 for all systems) is 0% if not shown.