
Figure 1.
Technological diagram of the WTP in Stary Sącz [16]
Table 1.
Efficiency of water pollutant removal at individual stages of the treatment process
| 2018–2022 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Indicator | Unit | Sampling point | Number of samples | Value | median | standard deviation | ||
| min. | average | max. | ||||||
| turbidity | NTU | Dunajec river | 804 | 0.70 | 21.30 | 2550.00 | 7.60 | 107.20 |
| after the settlers | 804 | 0.60 | 5.90 | 133.00 | 4.00 | 6.50 | ||
| after the filter Dyna Sand | 871 | 0.09 | 0.22 | 0.81 | 0.20 | 0.06 | ||
| after ozonation | 846 | 0.10 | 0.20 | 0.50 | 0.20 | 0.00 | ||
| after carbon filters | 840 | 0.07 | 0.10 | 0.21 | 0.10 | 0.00 | ||
| after infiltration in the ground | 506 | 0.06 | 0.12 | 0.85 | 0.11 | 0.04 | ||
| treated water | 868 | 0.06 | 0.11 | 0.31 | 0.10 | 0.03 | ||
| color | mgPt·dm−3 | Dunajec river | 869 | 5.7 | 29.0 | 964.8 | 17.0 | 54.9 |
| after the settlers | 869 | 3.9 | 15.2 | 182.0 | 14.1 | 7.7 | ||
| after the filter Dyna Sand | 869 | 1.8 | 4.2 | 9.0 | 4.1 | 0.9 | ||
| after ozonation | 869 | 0.7 | 2.5 | 5.8 | 2.3 | 0.8 | ||
| after carbon filters | 874 | 0.0 | 1.2 | 3.1 | 1.1 | 0.6 | ||
| after infiltration in the ground | 517 | 0.9 | 2.2 | 3.8 | 2.2 | 0.4 | ||
| treated water | 875 | 0.0 | 0.9 | 3.6 | 0.9 | 0.7 | ||
| UVA 254nm | - | Dunajec river | 869 | 0.123 | 0.396 | 4.120 | 0.333 | 0.279 |
| after the settlers | 869 | 0.123 | 0.302 | 1.450 | 0.29 | 0.076 | ||
| after the filter Dyna Sand | 869 | 0.070 | 0.140 | 0.257 | 0.139 | 0.024 | ||
| after ozonation | 875 | 0.047 | 0.107 | 0.193 | 0.106 | 0.022 | ||
| after carbon filters | 874 | 0.000 | 0.071 | 0.126 | 0.074 | 0.026 | ||
| after infiltration in the ground | 875 | 0.000 | 0.092 | 0.133 | 0.092 | 0.012 | ||
| treated water | 517 | 0.046 | 0.064 | 0.115 | 0.067 | 0.026 | ||
| Permanganatate oxygen demand | mg·dm−3 | Dunajec river | 301 | 1.44 | 3.07 | 10.0 | 2.7 | 1.22 |
| after the settlers | 319 | 1.00 | 2.44 | 4.1 | 2.44 | 0.45 | ||
| after the filter Dyna Sand | 318 | 0.21 | 1.32 | 2.3 | 1.36 | 0.34 | ||
| after carbon filters | 333 | 0.00 | 0.93 | 1.76 | 0.96 | 0.28 | ||
| after infiltration in the ground | 313 | 0.00 | 0.94 | 3.54 | 0.34 | 0.27 | ||
| treated water | 254 | 0.00 | 0.78 | 1.56 | 0.82 | 0.34 | ||
| Fe total | mg·dm−3 | Dunajec river | 126 | 0.008 | 0.137 | 2.480 | 0.075 | 0.239 |
| after the filter Dyna Sand | 196 | 0.000 | 0.008 | 0.130 | 0.010 | 0.012 | ||
| after infiltration in the ground | 226 | 0.000 | 0.011 | 0.109 | 0.007 | 0.010 | ||
| treated water | 1101 | 0.000 | 0.008 | 0.090 | 0.006 | 0.007 | ||
| Mn | mg·dm−3 | Dunajec river | 56 | 0.0004 | 0.0142 | 0.0438 | 0.0094 | 0.0121 |
| after the filter Dyna Sand | 35 | 0.0000 | 0.0004 | 0.0017 | 0.0004 | 0.0003 | ||
| after infiltration in the ground | 56 | 0.0000 | 0.0001 | 0.0015 | 0.0000 | 0.0003 | ||
| treated water | 56 | 0.0000 | 0.0006 | 0.0244 | 0.0000 | 0.0032 | ||
| coli group bacteria | cfu·100cm−1 | Dunajec river | 84 | 10 | 1226 | 3468 | 1122 | 725 |
| after the filter Dyna Sand | 162 | 0 | 63 | 319 | 50 | 63 | ||
| after infiltration in the ground | 213 | 0 | 2 | 85 | 0 | 7 | ||
| treated water | 644 | 0 | 0 | 0 | 0 | 0 | ||
| Enterococcus faecalis | cfu·100cm−1 | Dunajec river | 107 | 0 | 248 | 2000 | 150 | 310 |
| after the filter Dyna Sand | 168 | 0 | 10 | 98 | 6 | 14 | ||
| after infiltration in the ground | 216 | 0 | 1 | 74 | 0 | 5 | ||
| treated water | 642 | 0 | 0 | 0 | 0 | 0 | ||
| Clostridium perfringens | cfu·100cm−1 | Dunajec river | 98 | 16 | 158 | 1000 | 119 | 141 |
| after the filter Dyna Sand | 166 | 0 | 3 | 5 | 1 | 5 | ||
| after infiltration in the ground | 8 | 0 | 2 | 0 | 2 | 2 | ||
| treated water | 461 | 0 | 0 | 0 | 0 | 0 | ||

Figure 2.
Reduction of turbidity in the WTP technological system

Figure 3.
Reduction of color in the WTP technological system

Figure 4.
Reduction of UVA254nm in the WTP technological system

Figure 5.
Reduction of permanganatate oxygen demand in the WTP technological system

Figure 6.
Reduction of Fetotal in the WTP technological system

Figure 7.
Reduction of Mn in the WTP technological system
Table 2.
Reduction of bacteria in the WTP technological system
| Indicator | Unit | sand filters | disinfection | ground infiltration |
|---|---|---|---|---|
| % reduction | % reduction | % reduction | ||
| coli group bacteria | min. | 20.0 | 100.0 | 98.4 |
| av. | 93.3 | 100.0 | 99.9 | |
| max. | 100.0 | 100.0 | 100.0 | |
| Enterococcus faecalis | min. | 32.1 | 100.0 | 95.0 |
| av. | 91.9 | 100.0 | 99.9 | |
| max. | 100.0 | 100.0 | 100.0 | |
| Clostridium perfringens | min. | 72.2 | 100.0 | 96.9 |
| av. | 97.5 | 100.0 | 99.9 | |
| max. | 100.0 | 100.0 | 100.0 |