Table 1 The sampling locations and characteristics of the samples collected from five DWDSs (A–E). Water samples in each location were collected in four seasons: winter (January to February), spring (March to May), summer (August to September), and autumn (October to December) in two consecutive weeks
From: Active eukaryotes in drinking water distribution systems of ground and surface waterworks
DWDS | Water source | Treatment process | Disinfection | Location | Distance (km) | Sample type* | Sample count | Average total chlorine (mg/l) | Range | Average temp. (°C) | Range |
|---|---|---|---|---|---|---|---|---|---|---|---|
A | Artificial groundwater | Aeration, lime stabilization, flocculation, clarification, addition of sulphuric acid, sand filtration | No disinfection | 1 | 2 | Cold | 8 | – | – | 12.7 | 8–18 |
2 | 8 | Cold | 8 | – | – | 10.6 | 7–14 | ||||
‘’ | ‘’ | Hot | 8 | – | – | 53.8 | 51–56 | ||||
3 | 11 | Cold | 8 | – | – | 9.2 | 6–14 | ||||
i | na | WM | 2 | – | – | na | na | ||||
B | Artificial groundwater | Aeration, lime stabilization, flocculation, clarification, sand filtration | No disinfection | 1 | 1 | Cold | 8 | – | – | 9.6 | 7–12 |
2 | 3 | Cold | 8 | – | – | 10.4 | 8–13 | ||||
‘’ | ‘’ | Hot | 8 | – | – | 57.7 | 53–62 | ||||
3 | 8 | Cold | 8 | – | – | 8.9 | 6–13 | ||||
i | na | WM | 2 | – | – | na | na | ||||
C | Surface water | Ferric sulfate coagulation, flotation, sand filtration, activated carbon filtration | UV-light, ClO2, Cl2 | 1 | 2 | Cold | 7 | 0.5 | 0.4–0.6 | 8.9 | 2–20 |
2 | 8 | Cold | 8 | 0.3 | 0.2–0.5 | 11.8 | 5–19 | ||||
‘’ | ‘’ | Hot | 8 | na | na | 50.6 | 43–54 | ||||
3 | 20 | Cold | 7 | 0.2 | 0.1–0.4 | 10.1 | 6–16 | ||||
i | na | WM | 2 | na | na | na | na | ||||
D | Surface water | Ferric sulfate coagulation, clarification, sand filtration, ozonisation, activated carbon filtration | UV-light, NH2, Cl2 | 1 | 5 | Cold | 8 | 0.1 | < 0.03–0.2 | 10.3 | 7–15 |
2 | 14 | Cold | 8 | 0.1 | 0.03–0.4 | 10.5 | 6–17 | ||||
‘’ | ‘’ | Hot | 8 | na | na | 54.6 | 51–58 | ||||
‘’ | ‘’ | Pipe | 3 | na | na | na | na | ||||
3 | 19 | Cold | 8 | 0.1 | < 0.03–0.3 | 8.1 | 5–13 | ||||
i | na | WM | 1 | na | na | na | na | ||||
E | Groundwater | Aeration, limestone filtration | UV-light, NaOCl | 1 | 9 | Cold | 8 | 0.2 | 0.1–0.4 | 6.2 | 5–9 |
2 | 26 | Cold | 9 | 0.1 | 0.1–0.2 | 7.0 | 5–11 | ||||
‘’ | ‘’ | Hot | 8 | na | na | 54.1 | 49–59 | ||||
‘’ | ‘’ | Pipe | 3 | na | na | na | na | ||||
3 | 36 | Cold | 8 | 0.2 | 0.1–0.5 | 6.0 | 4–10 | ||||
i | na | WM | 3 | na | na | na | na |