Search

This paper presents an environmental analysis of the impact of an emergency discharge of untreated municipal sewage from the sewage system in Warsaw. This study was based on monitoring water quality in the Vistula River at stations located before and after the discharge site. Statistical analysis, including correlation analysis and Friedmann’s test, was performed for the data covering eight measurement stations and sixteen chemical parameters. The results confirm the negative impact on the water quality in the river, especially in the mixing zone. In the mixing zone, a statistically significant increase in pollution was found for TN, N-NO3−, N-NH4+, TP, P-PO43+, SS, EC, COD, and TOC. The results of the analysis show the self-cleaning capacity of the river ecosystem and illustrate the response to a sudden, excessive influx of pollution. The direct impact of the untreated sewage discharge was found on a section of the river 1200 m after the place of the failure. The good ecological status and drinking water standards are not met in the mixing zone. The supply of water to the people requires the use of highly effective physical and chemical treatment.

In this study, we aimed to develop a mathematical description of the process of phosphate sorption on Rockfos® material using the Langmuir isotherm and determine the basic parameters for modeling this process. The Rockfos® material was formed through the thermal treatment of opoka at 980 °C and is highly reactive due to its significant calcium and silicon compound content. This study included an evaluation of the phosphate retention efficiency on the material as a function of the phosphate concentration in the initial solution (0.5 mg/L, 1.0 mg/L, and 2.0 mg/L), sorbent grain size (1.0–1.6 mm, 1.6–2.5 mm, and 2.0–5.0 mm), and process temperature (5 °C, 10 °C, 15 °C, 20 °C, and 25 °C). It was found that an increase in the process temperature and the phosphate concentration in the solution favored sorption, while the effect of the sorbent grain size was ambiguous. It was determined that sorption can be described well using the Langmuir linearization of the Langmuir model. Thermodynamic analysis and the separation coefficient suggest that phosphorus sorption on Rockfos® material is primarily based on chemisorption, and the process is endothermic and spontaneous over the entire temperature range. The determined parameters of the tested material, especially the qmax (maximum sorption capacity), provide a basis for the design of a filter for removing phosphate from wastewater, assuming that the load is equal to the inflow to the filter and adheres to the specified requirements for treated wastewater.

The problem of wastewater discharged from facilities for soilless plant cultivation is a worldwide problem. So, there is a strong need to find a simple, maintenance-free technological solution. Such a solution may be the use of biofilters or constructed wetlands with “active” filling, which will be a source of carbon for denitrifying organisms. The aim of this study was to evaluate four different types of materials—Oxytree wood chips (Paulownia Clon in vitro 112®), biobased polybutylene succinate derivatives (BioPBS FZ91PB and BioPBS FD92PB), and beech wood chips—as biofilter media and as solid exogenous carbon sources. The highest efficiency of denitrification and dephosphatation (43.11% and 42.48%, respectively) was characterized by the biobased polybutylene succinate FD92PB. The lowest removal efficiency of phosphorus compounds was achieved for beech chips—25.23% and BioPBS FZ91PB—26.42%. The lowest denitrification efficiency—8.8%—was achieved by Oxytree wood chips. The extent of organic matter (COD) repollution in the treated wastewater requires further study. Wood chips were found to release less COD than biobased polybutylene succinate. The research results showed that all tested materials can be a source of carbon in soilless tomato cultivation wastewater treatment. This is a good starting point for further research on selecting appropriate process parameters and creating new solutions for reactor construction.

The aim of this study was to determine the quality of rainwater and the possibility of using it for various purposes in the Roztocze National Park (RNP), Poland. This study was carried out in 2021–2022. Samples of rainwater that drained from the roofs of farm buildings in the RNP were tested for their organoleptic, physicochemical and microbiological qualities. The organoleptic tests were run to evaluate the water for a foreign odour and the threshold odour number. The physical and chemical tests included turbidity; colour; pH; conductivity; concentrations of ammonium ions, nitrates, nitrites, manganese, iron and chlorides; and general hardness. The microbiological tests included total microbial counts at 36 °C and 22 °C, coliform bacteria, Escherichia coli, intestinal enterococci and Pseudomonas aeruginosa. The rainwater quality results were compared with the quality parameters of surface water collected from the River Świerszcz, as well as with the Polish drinking water standards. The findings indicated that rainwater collected in the RNP had good organoleptic, physicochemical and microbiological properties, which, in some cases, complied with the standards for potable water. Exceedances of the permissible limits, mainly for ammonium ions and microbiological indicators, were periodically observed in the tested rainwater. This was probably due to contamination of roof surfaces with bird droppings. However, these exceedances did not exclude the use of the rainwater for economic purposes, e.g., flushing toilets, washing vehicles or watering plants, which may significantly reduce the abstraction of high-quality groundwater. The rainwater that is planned to be used as drinking water for the Polish konik horses living in the park will have to be pre-treated via filtration and disinfection processes (e.g., with a UV lamp).

Due to the high nitrogen and phosphorus concentrations in wastewater from soilless cultivation of tomatoes, the sludge formed during wastewater treatment can be used as a source of nutrients in agriculture. The effect of electrical direct current (DC) density (J) and hydraulic retention time (HRT) in a rotating electrobiological contactor (REBDC) on the quantity and quality of sludge generated in the process of tomato soilless cultivation wastewater treatment was determined. The cathode consisted of discs immobilized with biomass, while the anode was an aluminum electrode. HRTs of 4 h, 8 h, 12 h, 24 h and (J) of 0.63, 1.25, 2.50, 5.00, and 10.00 A/m2 were applied. The study showed that the increase in (J) caused an increase in the amount of sludge generated. The increase of (J) contributed to increased concentrations of biogenes in the sludge, whereas extension of HRT at a given current density contributed to increased concentrations of nitrogen and phosphorus (up to 6.2% and 0.8% respectively) and to the reduced content of organic matter (up to 23.04%). The examined sludge was stabilized, sanitary, and safe, and may be an alternative to mineral fertilizers. This study showed that larger sludge amounts are produced in a DC mode aerobic REBDC than in an alternating current anaerobic one.

The results of research on the efficiency and technological reliability of domestic wastewater purification in two household wastewater treatment plants (WWTPs) with activated sludge are presented in this paper. The studied facilities were located in the territory of the Roztocze National Park (Poland). The mean wastewater flow rate in the WWTPs was 1.0 and 1.6 m3/day. In 2017–2019, 20 series of analyses were done, and 40 wastewater samples were taken. On the basis of the received results, the efficiency of basic pollutant removal was determined. The technological reliability of the tested facilities was specified using the Weibull method. The average removal efficiencies for the biochemical oxygen demand in 5 days (BOD5) and chemical oxygen demand (COD) were 66–83% and 62–65%, respectively. Much lower effects were obtained for total suspended solids (TSS) and amounted to 17–48%, while the efficiency of total phosphorus (TP) and total nitrogen (TN) removal did not exceed 34%. The analyzed systems were characterized by the reliability of TSS, BOD5, and COD removal at the level of 76–96%. However, the reliability of TN and TP elimination was less than 5%. Thus, in the case of biogenic compounds, the analyzed systems did not guarantee that the quality of treated wastewater would meet the requirements of the Polish law during any period of operation. This disqualifies the discussed technological solution in terms of its wide application in protected areas and near lakes, where the requirements for nitrogen and phosphorus removal are high.