Figure 1.
![Changes in the amount of wastewater discharged in total (in thousands of dam3) in Poland [Own study based on CSO data [3]]](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64706f7083f1392090d6979d/j_acee-2019-043_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251206%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251206T200803Z&X-Amz-Expires=3600&X-Amz-Signature=0b51cd7e246958fa739170df78181cd1b93a2d0969352d4f5e1545edcbe8a03d&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 2.
Changes in the number of Escherichia coli bacteria subjected to ultrasound with increasing temperature during the process
| Time of sonication [min] | 20 kHz – continuous work | 20 kHz – pulsating work | 40 kHz | |||
|---|---|---|---|---|---|---|
| E. coli [cfu/cm3] | Temperature [°C] | E. coli [cfu/cm3] | Temperature [°C] | E. coli [cfu/cm3] | Temperature [°C] | |
| 0 | 1.61*107 | 21 | 2.52*107 | 21 | 2.39*107 | 21 |
| 3 | 1.30*107 | 23 | 1.85* 106 | 23 | 1.66*107 | 22 |
| 5 | 3.02*106 | 24 | 1.48*106 | 24 | 1.43*107 | 23 |
| 7 | 1.66*106 | 25 | 1.40*106 | 25 | 1.62*107 | 23 |
| 10 | 1.43*106 | 26 | 1.33* 106 | 25 | 1.12*107 | 24 |
| 15 | 8.00*105 | 28 | 1.17* 106 | 26 | 1.09*107 | 26 |
| 20 | 6.10*105 | 29 | 1.03*106 | 27 | 0.75*107 | 28 |