Table 5:
Comparison of microbiological targets for grab versus composite samples produced in the laboratory from samples collected from wastewater source each hour (Experiments 1-3B). p values of the one-sample T-test less than 0.05 indicate that the mean of the grab sample was statistically different than the value of the corresponding composite sample.
| Molecular and Microbial Targets | SARS-CoV-2 (gc/L) | SIV (gc/L) | PMMoV (gc/L) | B2M (gc/L) | FC (CFU/L) |
|---|---|---|---|---|---|
| Sample Type | Experiment 1B - Building Scale | ||||
| Grab Average (n=24) | 5.28 × 104 | 3.08 × 106 | 2.43 × 108 | 8.81 × 105 | 2.30 × 107 |
| Grab Median (n=24) | 4.55 × 103 | 2.32 × 106 | 1.32 × 108 | 8.58 × 105 | 9.00 × 106 |
| Grab [Min-Max] (Std. Dev) | [BDL * −9.7×105] (2.0×105) | [1.3×105–1.2×107] (2.7×106) | [6.0×107–1.9×109] (3.8×108) | [5.0×103–1.6×106] (4.1×105) | [BDL * −1.9×108] (4.0×107) |
| Composite 1B | 4.13 × 104 | 1.6 × 105 | 3.70 × 108 | 9.31 × 105 | 1.74 × 108 |
| One-Sample T-Test (p-value: two-tailed) | 0.775** | <0.001 | 0.112** | 0.567** | <0.001 |
| Sample Type | Experiment 2B - Cluster Scale | ||||
| Grab Average (n=24) | 2.82 × 105 | 7.26 × 106 | 1.38 × 108 | 1.08 × 106 | 2.42 × 107 |
| Grab Median (n=24) | 1.75 × 105 | 6.95 × 106 | 1.40 × 108 | 1.05 × 106 | 1.00 × 107 |
| Grab [Min-Max] (Std. Dev) | [6.2×104–2.0×106] (3.9×105) | [3.8×106–1.2×107] (2.4×106) | [5.8×107–2.6×108] (5.2×107) | [4.8×105–2.0×106] (4.5×105) | [1.0×103–1.5×108] (3.2×107) |
| Composite 2B | 3.16 × 105 | 4.38 × 105 | 1.27 × 108 | 9.59 × 105 | 6.80 × 107 |
| One-Sample T-Test (p-value: two-tailed) | 0.669** | <0.001 | 0.319** | 0.217** | <0.001 |
| Sample Type | Experiment 3B - Community Scale | ||||
| Grab Average (n=24) | 8.62 × 103 | 4.30 × 106 | 1.43 × 108 | 2.43 × 105 | 1.02 × 108 |
| Grab Median (n=24) | 7.63 × 103 | 4.59 × 106 | 1.50 × 108 | 2.61 × 105 | 9.50 × 107 |
| Grab [Min-Max] (Std. Dev) | [8.4×102–3.0×104] (6.1×10s) | [2.2×106–6.5×106] (1.1×106) | [9.1×107–2.1×108] (3.2×107) | [1.2×105–3.6×105] (7.0×104) | [3.7×107–1.7×108] (4.0×107) |
| Composite 3B | 1.16 × 104 | 6.07 × 105 | 1.66 × 108 | 2.25 × 105 | 4.21 × 108 |
| WWTP Composite | 9.12 × 103 | 6.22 × 106 | 1.78 × 108 | 2.90 × 105 | 2.38 × 108 |
| One-Sample T-Test (p-value: two-tailed) | 0.022 (UM) 0.689** (WWTP) |
<0.001 (UM) <0.001 (WWTP) |
0.002 (UM) <0.001 (WWTP) |
0.227** (UM) 0.003 (WWTP) |
<0.001 (UM) <0.001 (WWTP) |
*
BDL=Below Detection Limits. Detection limit for SARS-CoV-2 was 1.0×102 gc/L. Detection limit for FC was 1.0 × 10“ CFU/L.
**
denotes statistical equivalency between grab and composite sample types by Wilcoxon Signed Rank Tests/T-tests.