Table 6.
Distance and physicochemical characteristic effects on chlorine residual and Legionella spp. occurrence in ten reclaimed water systems.
| Site and Location a | Distance (Miles) | TOC (mg/L) | pH | Temp (°C) | Free Cl (mg/L) | Legionella (CFU/mL) | |
|---|---|---|---|---|---|---|---|
| CA-18 | Effluent | 0 | 5.0 ± 0.3 | 7.6 ± 0.1 | 20.5 ± 0.3 | N/A b | <3 |
| Reservoir | 0.004 | 4.8 ± 0.1 | 7.7 ± 0.3 | 23.1 ± 0.3 | 0.1 ± 0 | <3 | |
| DS1 | 0.3 | 4.9 ± 0 | 7.8 ± 0.3 | 20.8 ± 0.2 | 0.1 ± 0 | <3 | |
| DS2 | 1.5 | 4.6 ± 0.1 | 8.0 ± 0 | 21.3 ± 0.2 | 0.1 ± 0 | 3 | |
| DS3 | 2.5 | 4.7 ± 0.2 | 8.2 ± 0 | 19.6 ± 0.1 | 0.1 ± 0 | 46 ± 19 | |
| FL-1 | Effluent | 0 | 4.3 ± 0.1 | 7.7 ± 0.1 | 29.5 ± 0.1 | 2.03 ± 0.06 | 2300 |
| Reservoir | 0.05 | 4.1 ± 0 | 7.8 ± 0 | 28.9 ± 0.4 | 1.17 ± 0.15 | <3 | |
| DS1 | 0.4 | 4.2 ± 0 | 7.8 ± 0 | 29.1 ± 0.2 | 0.55 ± 0.05 | <3 | |
| DS2 | 1.1 | 3.9 ± 0 | 7.8 ± 0 | 27.5 ± 0.2 | 0.12 ± 0.03 | 3 | |
| DS3 | 2.7 | 3.8 ± 0 | 8.1 ± 0.1 | 27.0 ± 0.1 | 0.10 ± 0 | 29 ± 2 | |
| NC | Effluent | 0 | 6.0 ± 0 | 7.0 ± 0 | 21.1 ± 0.5 | 0.65 ± 0.09 | 36 |
| Reservoir | 7.9 | 5.7 ± 0.1 | 6.9 ± 0 | 16.3 ± 0.3 | 0.1 ± 0 | 55 | |
| DS1 | 0.8 | 6.0 ± 0 | 7.2 ± 0.1 | 17.3 ± 0.4 | 0.2 ± 0.03 | 9 | |
| DS2 | 8.0 | 6.1 ± 0.2 | 7.5 ± 0.1 | 16.4 ± 0.1 | 0.22 ± 0.03 | 47 ± 17 | |
| DS3 | 9.3 | 6.0 ± 0 | 7.1 ± 0.1 | 15.8 ± 0.4 | 0.67 ± 0 | 23 ± 9 | |
| CA-3 | Effluent | 0 | 6.8 ± 0.1 | 8.2 ± 0 | 22.6 ± 1 | 1.33 ± 0.06 | 660 ± 300 |
| Reservoir | 21.1 | 7.1 ± 0.1 | 7.6 ± 0 | 24.2 ± 0.3 | 0.16 ± 0.05 | 9 | |
| DS1 | 11.5 | 7.1 ± 0.1 | 8.5 ± 0.1 | 23.4 ± 0.2 | 1 ± 0 | 140 ± 30 | |
| DS2 | 17.9 | 7.1 ± 0.1 | 7.7 ± 0 | 24.7 ± 0.2 | 0.21 ± 0.04 | <3 | |
| DS3 | 26.9 | 6.7 ± 0 | 7.5 ± 0 | 23.3 ± 0.9 | 0.16 ± 0.02 | 6 | |
| CA-2 | Effluent | 0 | 6.1 ± 0.1 | 7.1 ± 0.1 | 23.5 ± 0.4 | 0.21 ± 0.04 | <3 |
| Reservoir | 0.002 | 7.1 ± 0.1 | 6.9 ± 0 | 29.6 ± 0.7 | 0.21± 0.02 | 1600 ± 1100 | |
| DS1 | 0.63 | 6.4 ± 0.1 | 7.2 ± 0 | 27.2 ± 0.2 | 0.15 ± 0.03 | 24 | |
| DS2 | 1.71 | 6.5 ± 0.1 | 7.1 ± 0 | 24.0 ± 0.5 | 0.14 ± 0.02 | 45 | |
| DS3 | 2.62 | 6.4 ± 0.1 | 7.2 ± 0 | 21.3 ± 0.1 | <0.01 | 3 | |
| CO-5 | Effluent | 0 | 7.5 ± 0.1 | 7.3 ± 0.1 | 23.6 ± 0.9 | 23.6 ± 0.9 | 130 |
| Reservoir | 0.006 | 7.5 ± 0.1 | 9.5 ± 0 | 27.8 ± 0.8 | 0.15 ± 0.03 | 460 ± 160 | |
| DS1 | 0.1 | 7.5 ± 0.1 | 7.3 ± 0 | 22.4 ± 0.9 | 0.14 ± 0.02 | 810 ± 340 | |
| DS2 | 1.3 | 6.3 ± 0 | 7.8 ± 0.1 | 23.6 ± 0.4 | 0.11 ± 0.01 | 220 ± 270 | |
| DS3 | 2 | 7.4 ± 0.1 | 7.3 ± 0 | 22.7 ± 1.0 | 0.18 ± 0.02 | 92 ± 2 | |
| CA-1 | Effluent | 0 | 4.9 ± 0 | 8.1 ± 0 | 26.7 ± 0.5 | 0.16 ± 0.04 | <3 |
| Reservoir | 0.1 | 5.7 ± 0 | 8.6 ± 0 | 19.9 ± 0.2 | <0.01 | 220 ± 270 | |
| DS1 | 2.3 | 8.1 ± 0.1 | 7.4 ± 0 | 21.0 ± 0.8 | 0.03 ± 0.03 | 3300 ± 1900 | |
| DS2 | 4.4 | 6.8 ± 0.1 | 7.6 ± 0 | 20.2 ± 0.6 | 0.14 ± 0.02 | 45 | |
| DS3 | 6.9 | 7.4 ± 0 | 7.7 ± 0 | 22.6 ± 0.2 | 0.13 ± 0.02 | 12 | |
| AZ-8 | Effluent | 0 | 6.1 ± 0.1 | 7.9 ± 0 | 15.2 ± 1.2 | 0.22 ± 0.03 | <3 |
| Reservoir | 0.9 | 2.4 ± 0 | 8.4 ± 0 | 17.0 ± 0.2 | 0.11 ± 0.04 | 12 | |
| DS1 | 0.1 | 1.7 ± 0 | 8.4 ± 0 | 13.9 ± 0.6 | 0.04 ± 0.02 | 30 | |
| DS2 | 1.2 | 1.7 ± 0 | 8.0 ± 0 | 13.8 ± 0.6 | 0.14 ± 0.02 | 3 | |
| DS3 | 2 | 2.0 ± 0 | 7.9 ± 0 | 13.5 ± 0.8 | 0.05 ± 0 | <3 | |
| TX-3 | Effluent | 0 | 7.5 ± 0.1 | 7.8 ± 0.2 | 22.9 ± 0.1 | 0.4 ± 0.3 | 120 ± 130 |
| Reservoir | 1.5 | 7.7 ± 0.1 | 7.4 ± 0.1 | 21.9 ± 1 | 0.3 ± 0.1 | 500 ± 310 | |
| DS1 | 1.9 | 6.4 ± 0.1 | 7.3 ± 0.1 | 22.5 ± 0.1 | 0.08 ± 0.03 | 3 | |
| DS2 | 4.9 | 5.5 ± 0.1 | 7.3 ± 0.1 | 22.1 ± 0.1 | <0.01 | 3 | |
| DS3 | 6.4 | 4.9 ± 0.1 | 7.9 ± 0 | 23.0 ± 0.3 | 0.06 ± 0.1 | 9 | |
| FL-5 | Effluent | 0 | 13.9 ± 0.2 | 7.4 ± 0 | 28.3 ± 0.1 | 1.53 ± 0.06 | 870 ± 990 |
| Reservoir | 0.04 | 15.0 ± 0 | 7.5 ± 0 | 26.9 ± 0.5 | 0.48 ± 0.08 | 45 ± 19 | |
| DS1 | 0.5 | 14.2 ± 0.1 | 7.7 ± 0 | 24.7 ± 0.2 | 0.14 ± 0.05 | 33 | |
| DS2 | 3.3 | 8.4 ± 0.1 | 7.2 ± 0 | 26.2 ± 0.2 | 0.08 ±0.03 | 105 ± 140 | |
| DS3 | 6.8 | 8.4 ± 0.1 | 7.1 ± 0 | 27.4 ± 0.3 | 0.13 ± 0.03 | 45 | |
| Mean | 6.8 c | 6.3 | 7.3 | 22.7 | 0.30 | 440 | |
| Median | 4.6 c | 6.2 | 7.6 | 22.9 | 0.15 | 94 | |
a Sampled in March (CA-18 and TX-3), April (FL-1, FL-5 and NC), May (AZ-8, CA-1, CA-2, CA-3) or July (CO-5) of 2013; b Not applicable (No chlorination); c Mean and median of total mile length of each system as opposed to the mean and median of respective sampling points. (Source: [25]).