TABLE 2.
Detection of norovirus, rotavirus, reovirus, enterovirus, somatic phages, and F-specific phages in sewage samples (both raw and treated sewage) and the virus removal at the sewage treatment plant
| Date | Sewage | Concn (95% confidence interval)
|
|||||
|---|---|---|---|---|---|---|---|
| Somatic phages (PFU/liter) | F-specific phages (PFU/liter) | Enteroviruses (PFU/liter) | Reoviruses (PFU/liter) | Noroviruses (PDU/liter) | Rotaviruses (PDU/liter) | ||
| 16 November 1998 | Raw | 3.5 × 106 (2.9 × 106 to 4.2 × 106) | 4.0 × 106 (3.4 × 106 to 4.7 × 106) | 191 (140-253) | 1,253 (1,114-1,403) | 7,035 (444 to 6 .3 × 104) | 4,690 (296 to 4.2 × 104) |
| 16 November 1998 | Treated | 3.6 × 105 (2.9 × 105 to 4.4 × 105) | 1.0 × 105 (9.2 × 104 to 1.2 × 105) | 39 (31-49) | 48 (39-59) | 896 (57-7,999) | 598 (38-5,333) |
| Calculated log 10 removal | 1.0 | 1.6 | 0.7 | 1.4 | 0.9 | 0.9 | |
| 21 December 1998 | Raw | 6.8 × 106 (6.3 × 106 to 7.3 × 106) | 6.8 × 106 (6.9 × 105 to 7.7 × 105) | 288 (226-361) | 2,143 (1,964-2,332) | 1.2 × 105 (7,359 to 1.1 × 106) | 763 (36-8,804) |
| 21 December 1998 | Treated | 3.0 × 105 (2.5 × 105 to 3.4 × 105) | 6.2 × 103 (5.3 × 103 to 7.2 × 103) | 7 (4-10) | 92 (83-102) | 1,367 (88 to 1.2 × 104) | 908 (57-8,106) |
| Calculated log 10 removal | 1.4 | 2.0 | 1.6 | 1.4 | 1.9 | −0.1 | |
| 11 January 1999 | Raw | 6.4 × 106 (5.0 × 106 to 8.1 × 104) | 1.2 × 106 (1.1 × 106 to 1.3 × 106) | 296 (186-424) | 555 (414-725) | 8.5 × 105 (5.3 × 104 to 8.0 × 106) | 5.5 × 104 (2,592 to 4.9 × 105) |
| 11 January 1999 | Treated | 1.0 × 106 (9.3 × 105 to 1.1 × 106) | 6.7 × 104 (5.9 × 104 to 7.6 × 104) | 10 (7-13) | 76 (68-85) | 7,499 (463 to 7.1 × 104) | 4,819 (228 to 4.3 × 104) |
| Calculated log 10 removal | 0.8 | 1.3 | 1.5 | 0.9 | 2.1 | 1.1 | |
| 4 February 1999 | Raw | 3.3 × 106 (3.0 × 106 to 4.0 × 106) | 7.5 × 105 (6.7 × 105 to 8.4 × 106) | 140 (99-190) | 416 (343-499) | 4.6 × 104 (2,896 to 4.1 × 104) | 3.1 × 104 (1,931 to 2.7 × 105) |
| 4 February 1999 | Treated | 1.5 × 105 (1.3 × 106 to 1.7 × 105) | 1.3 × 104 (1.2 × 104 to 1.4 × 104) | 5 (3-7) | 23 (19-28) | 4,283 (265 to 4.0 × 1 04) | 2.9 × 104 (1,763 to 2.7 × 105) |
| Calculated log 10 removal | 1.4 | 1.8 | 1.5 | 1.3 | 1.0 | 0.03 | |
| 25 February 1999 | Raw | 5.2 × 106 (4.5 × 106 to 6.0 × 106) | 3.5 × 106 (3.2 × 106 to 4.0 × 106) | 833 (587-1,141) | 111 (40-239) | 5,111 (322 to 4.6 × 104) | 339 (16-3,027) |
| 25 February 1999 | Treated | 1.9 × 105 (1.8 × 108 to 2.1 × 105) | 5.4 × 104 (4.8 × 104 to 6.2 × 104) | 12 (9-18) | 8 (5-12) | 3,582 (221 to 3.4 × 104) | 2.4 × 104 (1,475 to 2.2 × 105) |
| Calculated log 10 removal | 1.4 | 1.8 | 1.8 | 1.1 | 0.2 | −1.8 | |