The Chief Environmental Inspector has approved a report on inspections of wastewater treatment plants carried out in 2020-2022. The treatment plants that were inspected totaled 427 facilities, with 406 of them located in agglomerations with 10,000. residents or larger. The purpose of the analysis was to check whether the treatment plants meet the quality and quantity requirements of the discharged wastewater, with a particular focus on nutrients (nitrogen- and phosphorus-rich pollutants that increase the fertility of waters and cause eutrophication, among other things). The largest number of treatment plants was inspected in the province. Mazowieckie (50 pcs.), woj. Wielkopolska (48 pcs.) and voivodeship. Lower Silesia (43 units). Exceedances of the standards were found most often at treatment plants in the province. Subcarpathian – at 40 percent. The facilities from which the samples were taken.
Wastewater treatment plants inspected
Based on the data, obtained during inspections of wastewater treatment plants in 2020-2022 by the Provincial Environmental Inspectors (VEOs), a report was created on June 30, 2023. was approved by the Chief Environmental Inspector. The report assessed the degree of compliance with the requirements for treatment plants located in agglomerations above 10,000. p.e. (population equivalent) and included in the National Urban Wastewater Treatment Program. Measurements of the quality of wastewater discharged from these treatment plants are also presented.
The audit evaluated the last two full periods of water permits, integrated and calculated as either 365 or 366 days. The beginning of each period is the date on which the permit became final, which means that the evaluation period is not the same as the calendar year. As communicated by the GIOŚ, 427 wastewater treatment plants were inspected in the first period, and 425 of them in the second period, because as of the date of completion of the WIOŚ inspection, two treatment plants could not be fully assessed for the second period due to permits issued in 2021.
Wastewater treatment plants – scope of inspections carried out
As of January 2016. there is an obligation to measure the share of total nitrogen and total phosphorus in treated wastewater in agglomerations of 10,000 or more. RLM. Data provided by the WIOŚ shows that of all 427 (i.e., all WWTPs, regardless of agglomeration p.e.) WWTPs inspected during this cycle of operation, 15 do not have conditions for nutrient discharge, in light of current water permits.
During the first period under review, the treatment plants were found to have failed to meet the conditions specified in their permits in the following areas:
- The condition and composition of wastewater for 42 of the 427 (9.8 percent) treatment plants inspected;
- the amount of wastewater discharged for 20 of the 427 (4.7 percent) treatment plants inspected;
- The condition and composition of wastewater and the amount of wastewater discharged for 6 of the 427 (1.4 percent) treatment plants inspected.
On the other hand, during the second period under review, the wastewater treatment plants were found not to meet the conditions specified in their permits in terms of:
- condition and composition of wastewater for 44 of the 425 (10.4 percent) treatment plants inspected;
- the amount of wastewater discharged for 17 of the 425 (4.0 percent) treatment plants inspected;
- The condition and composition of wastewater and the amount of wastewater discharged for 5 of the 425 (1.2 percent) treatment plants inspected.
The report shows that in the vast majority of cases – approx. 98 percent. of the inspected wastewater treatment plants – met the conditions, specified in the permit, both in terms of the condition and composition of wastewater, as well as its discharged quantity. In 353 out of 423 (82.7 percent) samples of treated wastewater taken during the inspection, there were no exceedances of the permissible concentrations of pollutant indicators specified in the permits held. The largest number of substandard wastewater treatment plants is located in the province. Podkarpackie (40.0 percent of the treatment plants sampled), woj. West Pomeranian (35.0 percent), voivodeship. Lower Silesia (26.2 percent) and in the voivodeship. Mazowieckie (26.0 percent).
The most common violations found during inspections were:
- Exceeded limit values for the pollution index (including total nitrogen, total phosphorus);
- Sampling of wastewater at sites that do not comply with the permit;
- determination of pollutant indicators by methods other than reference methods;
- lack of the required number of wastewater samples taken;
- performance of tests by unaccredited laboratories;
- Exceeding the 24-hour average quantity of treated wastewater discharged.
Wastewater treatment plants – water as a receiver of wastewater
Data presented in the report shows that the majority of wastewater treatment plants in Poland discharge into surface waters.
According to the permits held from the 427 treatment plants inspected:
- 39 (9.1 percent) discharge wastewater into the ground,
- 388 (90.9 percent) discharge wastewater into waterways.
Discharging insufficiently treated wastewater (i.e., in excess of the standards specified in the permits held) can have a negative impact on surface waters and result in, among other things. Eutrophication. You can learn about how to properly discharge wastewater in the guide: “Three Steps to … Proper Wastewater Disposal, or How to Obtain a Permit to Discharge Wastewater into Surface Water.”
Source: report https://www.gov.pl/web/gios/rok-2023-raporty (accessed 19.07.2023)