Table 4.
Cycle Thresholds (Ct) values of SARS-CoV-2 gene targets at each treatment stage in 3 WWTPs
| WWTP | Wastewater sample type | N1 gene | ORF1b- nsp14 gene | RdRp gene | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Positives n, (%) | Ct (mean ± SD) | Mean gene copies/100 mL (95% CI) | Positives (n, %) | Ct (mean ± SD) | Mean gene copies/100 mL (95% CI) | Positives (n, %) | Ct (mean ± SD) | Mean gene copies/100 mL (95% CI) | ||
| WWTP-Z3 | Raw | 23 (85.2) | 33.79 ± 1.62 | 8.68 × 104 (5.31 × 104–1.20 × 105) | 23 (85.2) | 33.36 ± 1.53 | 1.13 × 105 (7.61 × 104–1.50 × 105) | 18 (66.7) | 34.45 ± 1.73 | 9.04 × 104 (4.75 × 104–1.33 × 105) |
| Secondary treated | 2 (7.4) | 34.79 ± 1.25 | 3.08 × 103 (− 1.87 × 103–8.03 × 103) | 3 (11.1) | 35.21 ± 1.05 | 4.59 × 103 (− 1.15 × 103–1.03 × 104) | 3 (11.1) | 36.01 ± 0.53 | 4.41 × 103 (− 8.07 × 102–9.62 × 103) | |
| WWTP-Z5 | Raw | 16 (72.7) | 31.53 ± 1.94 | 3.04 × 105 (1.67 × 105–4.41 × 105) | 15 (68.2) | 30.67 ± 1.29 | 3.52 × 105 (2.02 × 105–5.02 × 105) | 15 (68.2) | 32.03 ± 1.67 | 3.18 × 105 (1.83 × 105 − 4.53 × 105) |
| Secondary treated | 0 | – | – | 0 | – | – | 0 | – | – | |
| Tertiary treated | 0 | – | – | 0 | – | – | 0 | – | – | |
| WWTP-Z1 | Raw | 8 (57.1) | 33.79 ± 1.5 | 6.03 × 104 (− 5.18 × 103–1.26 × 105) | 9 64.3) | 34.3 ± 1.5 | 4.76 × 104 (5.98 × 103–8.93 × 104 | 8 (57.1) | 35.81 ± 1.04 | 2.89 × 104 (8.6 × 103–4.91 × 104) |
| Secondary treated | 0 | – | – | 0 | – | – | 0 | – | – | |
| Tertiary treated | 0 | – | – | 0 | – | – | 0 | – | – | |