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The paper presents the results of a study of parameters used for determining the amount of organic pollutants in wastewater flowing into a collective wastewater treatment plant with a population equivalent of about 120 000 PE. The plant constituted part of a sewage system. Assays were performed for biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), permanganete index (CODMn) and total organic carbon (TOC). In addition, the pH of wastewater and its alkalinity were determined. Sampling of incoming wastewater and measurement of physicochemical parameters were performed once a week, in the spring. A total of 44 samples of wastewater were collected. The correlations between the individual parameters and the correlations between the ratios of these parameters were determined. It was found that it was possible to estimate, with suffi cient accuracy, the values of selected parameters for determining the concentrations of organic compounds in municipal wastewater, knowing the values of other parameters in this group. Moreover, it was shown that, knowing the relationship between the analyzed parameters, one can find multiple regression equations for a given type of wastewater, which allow one to calculate the remaining relationships with a good fit, i.e. a determination factor R2greater than 0.6

The sludge generated from wastewater treatment facilities contains high nutrients and is characterized by high heating values. Thus, the sludge enriched with organic matter and nutrients is a potential candidate for its application as fertilizers and an alternate energy feedstock. Nowadays, energy independence contributes to the economic stability of the country, and therefore the search for alternate energy sources is an acute issue. This paper presents a case study on using sewage sludge as an energy feedstock in Poland. The physicochemical characteristics of the sewage sludge are presented. The fuel properties of sewage sludge generated from different waste water treatment plant (WWTP) are summarized. The calorific value of sewage sludge generated in Poland is insufficient for effective use as an energy raw material, therefore, energy potential of mixture of sludge with other waste have been studied. The general trend of sewage sludge formation and the quantitative forecast for the future showed that in 2020, compared to 2012, sludge accumulation increased by 6.9%, but compared to 2019 - decreased by 3%. From 2012 to 2020 the average, sewage sludge accumulation increased annually by 0.8%. This demonstrates the heterogeneity of waste streams for the production of alternative fuels and a modest increase in sewage sludge production in the coming years. This made it possible to prepare several options for the further development of research in the field of developing technologies for obtaining alternative energy. Also this study will help the prospective researchers understand sewage sludge generation and its use as energy feedstock.

This study analyzed the effect of lightweight aggregates made of fly ash from sewage-sludge thermal treatment (FASSTT LWA) on the effectiveness of phosphorus removal from wastewater in vertical constructed wetlands (CWs), depending on FASSTT LWA content in the CW filling and hydraulic loading rate. It was performed over 13 weeks using 15 lysimeters prepared as double-layer systems. An upper layer was made of FASSTT LWA above the gravel layer with different thicknesses of FASSTT LWA (CW 0 cm: only gravel; CW 12 cm, CW 25 cm; CW 50 cm, and CW 100 cm: only FASSTT LWA). Each filling variant was repeated three times. Wastewater with a mean phosphorus concentration of 7.43 mgP/L was fed to the lysimeters once a day. The hydraulic loading rates tested were 3.0, 5.0, and 7.0 mm/d. Both the increased FASSTT LWA content in the CW filling and the decreasing hydraulic loading rate were found to boost the effectiveness of phosphorus removal in the treated wastewater. Constructed wetland filled in 100 % with FASSTT LWA ensured a reduction in phosphorus concentration below 2.0 mg P/L at all hydraulic loading rates tested.

This paper presents the results of a study on the possibility of applying various configured filters filled with a mixture of Rockfos® and Leca® material for the effective capture of phosphate from domestic wastewater. The tests were carried out for two years at two wastewater flow rates (20 and 40 L/day) in three pairs of filtration columns with a volume of filter material equal to 20 L each. Columns 1A and 1B were filled only with Rockfos®. Columns 2A and 2B contained Rockfos® and two 5-cm layers of Leca®. Columns 3A and 3B were filled with Rockfos® and a 10% addition of Leca®. A high phosphate removal efficiency was obtained at a level of 93.2–94.9% for all columns tested at a flow rate of 20 L/day with a retention time of 12 h. After 250 days of the experiment, the efficiency of phosphate removal decreased significantly, which was associated with a drop in the temperature of the inflowing wastewater (3 Rockfos® with the addition of Leca® in 1 m3/day of wastewater inflow.

The present study was focused on the characterization of the biocenotic diversity of saprotrophic fungi, taking into account the impact of various treatment systems and technological stages as well as the physicochemical properties of wastewater. The biodegradation potential, the hazard posed to humans, animals, and the environment, and the effectiveness of elimination of propagules were evaluated. The most effective elimination of fungal propagules was recorded in hybrid constructed wetland systems with horizontal (HF-CW) and vertical (VF-CW) wastewater flow, especially in the VF-HF objects. The fungal communities present in wastewater from small constructed wetland (CW) and wastewater stabilization ponds (WSP) were dominated by ubiquitous terrestrial molds accompanied by a minimal number of yeasts. The similarity of the species composition of the fungal communities between the treatment plants was generally low, whereas the species diversity together with the population size was very high at the various stages of wastewater treatment. Species with potential pathogenicity to humans and animals accounted for over 45%, i.e., were classified as BioSafety Level 1 and 2 (BSL-1 and BSL-2 groups), and potentially phytopathogenic fungi represented 31.5% of the mycobiota species composition. The dynamics of fungal growth were correlated with the content of organic pollutants and nutrients (nitrogen and phosphorus) and with oxygen deficiency. The accumulation of nitrates corresponded to the decline in the frequency of fungi in treated wastewater. The lowest efficiency of the removal of fungi was exhibited by the biological wastewater stabilization ponds.

In the study, the Weibull reliability theory was used to analyze the reliability of a small Sequencing Batch Biofilm Reactor (SBBR) for domestic wastewater purification. Also, the relative frequency and probability of exceedance of effluent discharge limits for the analyzed pollution parameters (BOD5, COD, total suspended solids, total nitrogen and total phosphorus) were determined. Full technical scale tests were carried out at a facility with a mean throughput of 0.6 m3/d, for a period of 34 months from December 2016 to September 2018. An analysis of the test results regarding the reliability of removal of the contaminants to the maximum effluent discharge levels yielded the following figures: BOD5 – 77.5%, COD – 97.8%, TSS – 100%, TN – 12.2% and TP – 21.7%. The relative exceedance frequencies measured in treated wastewater, expressed as proportion of all measurement series for a given parameter were: BOD5 – 17.14%, COD – 3.7%, TSS – 0%, TN – 85.2% and TP – 81.2%. The study showed that the small SBBR system was reliable in removing the basic contaminants (TSS, BOD5, COD) from domestic wastewater, but did not ensure effective removal of biogenic compounds. Large-scale use of this type of treatment plants may contribute to the eutrophication of wastewater receivers.

The aim of this study is to analyse the possibilities of use of waste from dairy production to produce electricity and heat in the process of anaerobic digestion. The analysis covers one of the Polish dairies located in Eastern Poland. The amounts of the substrates produced in analyzed dairy plant will enable the production of approx. 14,785 MWh electricity and 57,815 GJ of heat. This will allow the construction of biogas plant with an electrical power of 1.72 MW. The paper has been stated that the construction of biogas plants for environmental and social reasons is beneficial.

In this paper, we analysed the pollutant removal efficiency and reliability of a vertical and horizontal flow hybrid constructed wetland (CW) planted with giant miscanthus and Jerusalem artichoke. The wastewater treatment plant, located in south-eastern Poland, treated domestic sewage at an average flow rate of 1.2 m3·d−1. The tests were carried out during. 5-years of operation of the sewage treatment plant (2011–2016). During this period, sewage samples were collected from three stages of wastewater treatment in four seasons (winter – February, spring – May, summer – August, and autumn – November). The following parameters were measured: BOD5, COD, total suspended solids, total nitrogen, and total phosphorus. The average effectiveness of organic pollutant removal expressed by BOD5 and COD was 98.8 and 97.6%, respectively, and the removal efficiency for total suspended solids was 93%. The average values of BOD5, COD, and total suspended solids in wastewater discharged to the receiver were significantly lower than the limit values required in Poland. The efficiency of total nitrogen and total phosphorus removal was 64.1 and 68.1%, respectively, and the average values of these components in the outflow from the treatment plant exceeded the standard levels. A reliability analysis performed using the Weibull probability model showed that the reliability of pollutant removal in the tested CW system was very high for BOD5 and COD (100%). It was also demonstrated that the tested CW did not provide effective elimination of biogenic elements (nitrogen and phosphorus), as evidenced by the low reliability values – 32 and 28%, respectively. The investigated hybrid CW system with giant miscanthus and Jerusalem artichoke removed organic and biogenic pollutants with a similar efficiency as systems using classic plant species such as reed and willow.

This paper is a review of research and experiences related to the application of constructed wetland systems (CWs) in southeastern Poland in 1992–2016. On the basis of literature data, a comparison between pollutant removal efficiencies of one-stage and hybrid CWs was made. Some problems regarding the operation of these treatment plants were also presented. Data from various facilities indicate that one-stage CWs with horizontal or vertical flow were characterised by a quite high (80–89%) efficiency of removal of BOD5, COD and total suspended solids, but were less efficient in removing of biogenic compounds nitrogen and phosphorus – respectively 59 and 66%. Significantly higher removal efficiencies for the basic pollutants (above 92%) were observed in hybrid CWs with a VF–HF bed configuration. Those facilities removed ca. 65% of total nitrogen and 89% of total phosphorus. A statistical analysis revealed that hybrid VF–HF type CWs were characterised by a very high, about 99%, operation reliability. Lower reliabilities were achieved by one-stage CWs, especially those with a VF bed. Twenty five years of research on and experiences in the application of CWs in southeastern Poland indicate that one-stage CWs can be used on a larger scale in Polish conditions in rural areas with a scattered housing structure. Hybrid systems, on the other hand, can be applied successfully in recreational centres or in protected areas, especially in national parks, where a high pollutant removal efficiency is required. It has been shown that the use of hybrid CWs is consistent with the idea of sustainable development.

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.

The paper presents the results of a 3-year study on the technological reliability and the efficiency of typical domestic wastewater treatment in two hybrid constructed wetland systems (CWs) located in the area of the Roztocze National Park (Poland). The studied objects consist of an initial settling tank and a system of two beds of the vertical flow (VF) and horizontal flow (HF) (VF&ndash, HF) type with reed and willow. The wastewater flow rate in the constructed wetlands systems (CWs) was 0.4 and 1.0 m3/d, respectively. During the study period (2017&ndash, 2019) 20 series of analyses were performed and 60 wastewater samples were collected. Based on the obtained results the effects of pollutant removal and the technological reliability were determined, which were specified with the Weibull method. The average efficiency of biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) removal was 96&ndash, 99%. Slightly lower effects were obtained in the case of total phosphorus (TP) removal (90&ndash, 94%), as well as for total suspended solids (TSS) (80&ndash, 87%) and total nitrogen (TN) (73&ndash, 86%) removal. The analysed CWs were characterised by 100% technological reliability for BOD5 and COD, as well as a good reliability for TSS and TP (87&ndash, 100%) but slightly lower for TN removal (35&ndash, 89%). Hybrid CWs of VF&ndash, HF type should be recommended to use in protected areas for wastewater treatment and water resources quality protection.

Data for the years 2001–2020 on changes in the amount of rainwater in the Roztocze National Park (RNP) in the catchment area of the Świerszcz River (Poland) were investigated to evaluate the possibility of using rainwater in the park for various purposes in the context of ongoing climate variability. An analysis of data from the RNP’s Integrated Monitoring of the Natural Environment showed that the average annual air temperature increased by 2.1 °C over the 20-year period, while the amount of precipitation decreased, especially in the winter seasons. These changes periodically led to a negative hydrological balance. As an effect, the groundwater table was gradually lowering, the flow of the Świerszcz River was reduced, and there were periodic shortages of water feeding the Echo Ponds. Water shortages also negatively affected the flora and fauna of the RNP. In order to quantitatively protect the Park’s water resources, a proposition was made to build a rainwater management system at the Animal Breeding Centre in Florianka to provide water for watering Polish Konik horses, flushing toilets, washing cars and agricultural equipment, and fire-prevention purposes. The excess water would be discharged to a nearby pond, which is an amphibian breeding site. It was estimated that the system was capable of meeting 100% of the demand for lower-quality water in the summer period. Moreover, it was determined that 9109 m3 of rainwater could be obtained annually from the roofs of all public utility buildings located in the RNP.

The paper presents the results of a study of selected parameters of common osier (Salix viminalis) biomass sampled annually, over a 12-year period, from a constructed wetland wastewater treatment plant. The focus of the study was on parameters that were relevant to biomass energy management. The study was conducted in a constructed wetland wastewater treatment plant consisting of one horizontal flow bed with a total area of 186 m2, planted with osier willows. The following biomass parameters were analysed: biomass yield, volume, humidity, ash content, higher and lower heating values, and contents of N, P, K in different parts of plant stems. The study showed that osier biomass harvested from the investigated constructed wetland system could be used as an energy source in thermochemical processes. The higher and lower heating values were similar to those obtained by other authors (18.13 and 17.38 MJ·kg−1, respectively). The energy yield (17.49 MJ·m−2) and energy density (3486–5411 MJ·m−3) were also calculated. Young shoot parts had higher ash and micronutrient contents and lower energy parameters than old parts.

Recent years have seen an increasing interest in hybrid constructed wetland (HCW) systems for domestic sewage treatment. This paper is focused on kinetics of removal of the main pollutants occurring in wastewater i.e. organics expressed as chemical oxygen demand, biochemical oxygen demand and total nitrogen. The purpose of the article is to compare different HCW configurations in terms of mass removal rates (MRR) and removal rate coefficients (kA and kv). Analysed data have been collected at two wetland systems, each composed by two subsurface flow beds: horizontal flow (HF) and vertical flow (VF). Reliable evaluation was achieved by using the same composition of influent wastewater in both HCWs. Performance of opposite configurations HF + VF vs. VF + HF was compared after each stage and the overall HCW system. The average mass removal rates of COD, BOD5 and TN in both systems were similar, respectively: 2.30, 0.98 and 0.40 g m−2 d−1. However, removal rates differ between single wetland beds after each treatment stage.

The investigations were carried out in six small mid-forest peat bogs with active peat-forming processes, all situated in the Lublin region (Eastern Poland). The bogs represented two floristically different types of peatland: raised bogs and transitional mires species composition analysis and specific chemistry analysis (pH, Eh, carbon content, N, P, Mg, Na, Ca, Mn, Fe, dehydrogenase activity and water level) were performed. The plant assotiations/communities of the peat bogs represented three phytosociological classes: Scheuchzerio-Caricetea nigrae, Oxycocco-Sphagnetea, and Vaccinio-Piceetea. The analysis of redox potential measured in the different communities revealed differences in the Eh values between these phytocoenoses (p

The paper presents the results of the research about the efficiency of organic substance removal in a hybrid sand filter. The investigations were carried out on a model wastewater treatment plant consisting of a preliminary sedimentation tank and two sand filter with a horizontal flow of wastewater (aerobic and anaerobic beds). The efficiency of BOD5 and COD removal was analysed for different wastewater hydraulic load levels: 0.72; 1.08; 1.44 dm3·d−1. The best efficiency of BOD5 and COD removal was obtained when the hydraulic load level was 1.08 dm3·d−1, respectively 83.8 and 72.3%. The average values of BOD5 and COD in the treated wastewater were significantly higher than the values deemed acceptable by relevant regulations in Poland. Based on the studies in the analyzed case, it was found that, sand filters with horizontal flow, do not guarantee high effluent treatment effect of typical household wastewater. In order to obtain a better efficiency of organic substance removal in a hybrid sand filter wastewater need to be oxygenate before being carried to these systems.

This paper aims to analyze the variability of the levels of surface and ground water in the Ochożanka basin. The depth at which the ground water table occurred was studied with reference to the adopted land drainage standards. The studies were carried out in 2009/2010–2014/2015 for natural and regulated water outflows. The analysis of annual total precipitation in the analyzed period some years were very wet (2009/2010 and 2013/2014), some of them were wet (2010/2011, 2012/2013), one year was dry (2014/2015) and one year was normal (2011/2012). The six-year average seasonal precipitation amounted to 593 mm, which was 66 mm higher than average precipitation recorded in 30 years. Under regulated outflow conditions the level of water in the river ranged from 55 to 77 cm. The level of water under natural outflow ranged from 18 to 49 cm. In the area with regulated outflow the average ground water level was 47 cm. In the remaining area of drainage system ground water level was 67 cm. Also, the dynamics of variance in the water level under natural outflow conditions was clearly higher.

Hydropower plants in Poland currently use only 19% of the river’s energy potential. Development of hydropower is limited by environmental regulations as well as by economic grounds. From the environmental point of view, it is desirable to build small hydropower plants integrated into the local landscape. This paper presents results of the research aimed at estimating the amount of energy that could be produced in the case of small hydroelectric power plants on weirs existing on the Tyśmienica River. There is also a legal framework that should be adapted at hydropower development. It was calculated that the technical capacity of the small hydropower plants that could be built on 4 existing weirs, is 0.131 MW. These power plants could produce 786 MWh of electricity per year. The economic efficiency of this production is currently difficult to assess, because a new support system for renewable energy sources is currently being implemented, which will be a decisive factor for entrepreneurs. It should be borne in mind that potential investments will be made in protected areas within the Natura 2000 network, which may limit their constructing or impose the obligation to assess their impact on selected environmental elements. Location within the protective area does not eliminate such investments, especially when solutions with the least possible environmental impact are used.

The paper presents the results of a study of the reliability and efficiency of pollutant removal during long term operation of a one-stage constructed wetland system with horizontal flow. The flow rate of the wastewater treatment plant was 1.2 m 3 d −1 during the research period. Physical and chemical analyses of raw wastewater and treated effluent were carried out in the years 1997–2010 (14 years). During this study period, 56 series of analyses were performed and 112 wastewater samples were collected. The average efficiencies of BOD 5 (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand) and TSS (Total Suspended Solids) removal in the investigated facility during the 14 years of its operation were respectively: 84.7%, 80.9%, and 62.4%. The average values of these parameters in the treated wastewater were significantly lower than the values deemed acceptable by relevant regulations in Poland. The reliabilities of the wastewater treatment plant, based on the Weibull reliability theory for acceptable values of pollution parameters in the effluent of the treatment plant, were as follows: BOD 5 – 92%, COD – 98%, TSS – 90%. The conducted analysis showed that the operational reliability of the one-stage horizontal subsurface flow constructed wetland (HSFCW) over the operation period was insufficient according to the Polish standards. Improvement of the reliability of the analyzed system by introduction of additional purification elements, such as irrigated biological beds or a constructed wetland with vertical wastewater flow, was recommended.

The study investigated the efficiency of removal of iron, manganese and indicator bacteria from potable groundwater by using carbonate-silica rock (opoka). The tests were performed in a laboratory in three filter columns supplied with water containing increased concentrations of iron and manganese. Two of the columns were filled with carbonate-silica rock with particle sizes of 2-5 mm; retention time for water in the columns was set at 1 h and 2 h. A third column was filled with 1-2 mm rock particles, with hydraulic retention time set at 1 h. High removal efficiencies were determined for iron, manganese and coliform bacteria and low removal efficiencies for psychro- and mesophilic bacteria. An increase in the alkalinity of the investigated water was also observed.

The goal of this paper was to evaluate the possibility of using terrestrial laser scanning (TLS) for inventorying of a hybrid constructed wetland (CW) wastewater treatment plant. The object under study was a turtle-shaped system built in 2015 in Eastern Poland. Its main purpose is the treatment of wastewater from the Museum and Education Centre of Polesie National Park. The study showed that the CW system had been built in compliance with the technical documentation, as differences between values obtained from the object and those given in the design project (max. ± 20 cm for situation and ±5 cm for elevation) were within the range defined by the legislator. It was also shown that the results were sufficiently precise to be used for as-built surveying of the aboveground elements of the CW system. The TLS technique can also be employed to analyse quantitative changes in object geometry arising during long-term use (e.g. landmass slides or erosion), the identification of which can help in selecting the hot-spots at risk of damage and thus restore the object to its original state as well as prevent new changes.

The aim of the present study was to assess the technological reliability of a domestic hybrid wastewater treatment installation consisting of a classic three-chambered (volume 6 m3) septic tank, a vertical flow trickling bed filled with granules of a calcinated clay material (KERAMZYT), a special wetland bed constructed on a slope, and a permeable pond used as a receiver. The test treatment plant was located at a mountain eco-tourist farm on the periphery of the spa municipality of Krynica-Zdrój, Poland. The plant's operational reliability in reducing the concentration of organic matter, measured as biochemical oxygen demand (BOD5) and chemical oxygen demand (COD), was 100% when modelled by both the Weibull and the lognormal distributions. The respective reliability values for total nitrogen removal were 76.8% and 77.0%, total suspended solids – 99.5% and 92.6%, and PO4-P – 98.2% and 95.2%, with the differences being negligible. The installation was characterized by a very high level of technological reliability when compared with other solutions of this type. The Weibull method employed for statistical evaluation of technological reliability can also be used for comparison purposes. From the ecological perspective, the facility presented in the study has proven to be an effective tool for protecting local aquifer areas.

The paper presents the results of application of hydrogen peroxide (H2O2) for the optimization of the effects of ammonia nitrogen removal from domestic wastewater. The investigations were carried out at a model wastewater treatment plant consisting of a preliminary sedimentation tank and a sand filter with a horizontal flow of wastewater at a constant hydraulic load of 1.44 L/day. The efficiency of ammonia nitrogen removal was analyzed for different wastewater oxygenation levels: 0–10%, 10–20%, 20–30%, 30–40% and 40–50%, maintained by controlled application of a 0.1% H2O2 solution. It was demonstrated that the gradual increase in oxygen concentration in treated wastewater due to H2O2 dosing resulted in an increase in ammonia nitrogen removal from 39.0 to 81.2%. The best removal efficiency was obtained when the oxygenation level was in the range of 30–40%. It was also shown that application of hydrogen peroxide resulted in an effective removal of biochemical oxygen demand (BOD5). The highest BOD5 removal efficiency (94.3%) was obtained at the oxygenation level of 30–40%. The results indicate that oxygenation of wastewater with hydrogen peroxide can be applied for the optimization of the nitrification process in wastewater treatment plants.

The aim of study was the analyze of the reliability pollution removal in wastewater treatment plant in Mińsk Mazowiecki. The article presents the results of the reliability of BOD, COD and total suspended solids removal of wastewater treatment plant with actived sludge. Physical and chemical analyses of raw wastewater and treated effluent were carried out in the years 2016–2017 (2 years). The designed size of the treatment plant with actived sludge, expressed in PE is 82 200 residents. During this study period, 50 wastewater samples were collected and analyses. For each of pollution indicators descriptive statistic, percentage reduction and and treatment plant reliability factors (WN) were calculated. The average effectiveness of BOD5 (Biochemical Oxygen Demand), CODCr (Chemical Oxygen Demand) and TSS (Total Suspended Solid) removal in this period of study were respectively: 99.1%, 96.3% and 98.9%. A reliability analysis was performed using the Weibull probability model.

The aim of this work was to determine the technological reliability of pollutions removal in different seasons in one-stage constructed wetland system with horizontal flow operating in the conditions of moderate climate. In the above-mentioned system, willow (Salix Viminalis L.) was planted and the average flow of domestic sewage were 1.2 m3/d. The analyzed system is located in south-eastern Poland, where the climate is moderate transitional. The tests were carried out during the 14-year exploitation of the wastewater treatment plant (1997–2010). During this period, sewage samples were collected in 4 seasons (winter – February, spring – may, summer – August and autumn – November) to be analyzed. The average long-term air temperatures in these months were respectively: −1.8; 13.8; 18.3 and 3.5 °C. Altogether 56 series of analyzes were carried out during the research and 112 samples of the sewage, both from the inflow and the outflow of the wastewater treatment plant, were collected. The measured parameters were: BOD5, COD, total nitrogen, total phosphorus. On the grounds of the reliability analysis performed on the basis of the Weibull probability model, it was found that the reliability of pollutions removal in the tested constructed wetland system are higher in summer and autumn (August, November) than in winter and in spring (February, May). It was shown that exceedance of the admissible values ​​of pollutant indicators in treated wastewater is dependent on the season (air temperature) and it occurred mainly in the winter period (February). It was proved that the tested CW does not provide effective elimination of biogenic indicators (nitrogen and phosphorus), as evidenced by small values ​​of reliability. To increase the technological reliability of the tested treatment plant, it is proposed to expand the existing system and create a hybrid system consisting of two beds with vertical and horizontal flow and a special P-filter. info:eu-repo/semantics/acceptedVersion

tThe aim of the study was to determine the influence of the particle size of carbonate–silica rock (opoka)used in rock filters on the efficiency of phosphorus removal from domestic wastewater. The investigationswere carried out in a laboratory using a model consisting of three vertical flow filters with carbonate–silicarock of different particle sizes (G1= 1–2 mm; G2= 2–5 mm; G3= 5–10 mm). The tested rock was subjectedto decarbonising at 900◦C and consisted primarily of 51.7% SiO2, 23.2% CaO, and 7.6% Al2O3. In the firstthree weeks of the study (1–3), the hydraulic load of each filter was Q1= 0.72 l/day and the hydraulicresidence time was HRT1= 24 h; in the next three weeks (4–6) Q2= 1.08 l/day and HRT2= 16 h, and duringthe last three weeks (7–9) Q3= 1.44 l/day and HRT3= 12 h. A significant influence of the size of rock parti-cles and the hydraulic load (hydraulic residence time) on the efficiency of total phosphorus removal andon phosphorus concentration in the wastewater discharged from the system was observed ( = 0.05).Statistically, the best removal of phosphorus from wastewater – an average of 97%, was found in thesubstrate with the smallest particle size (rock G1, 1–2 mm) at the lowest hydraulic load of 0.72 l/dayand at a hydraulic residence time of 24 h. The lowest phosphorus removal efficiency was observed inthe filter containing rock G3with a particle size of 5–10 mm (mean

Under conditions of low funding for the production of “green energy” in Poland, it became necessary to search for other – cheaper sources of biomass and the development of more efficient technologies. The maize straw is waste material arising in the production of grain. Therefore currently has no wider application and the cost of acquisition is several times lower than in case of maize silage. This paper presents the results of research on biogas efficiency of the maize straw silage, the dynamics of the fermentation process and the decomposition time of biomass under the meso- and thermophilic conditions. Moreover, the exploitation costs of a biogas plant working on this substrate and maize silage have been compared. It has been proved that thermophilic fermentation is significantly shorter (17%) than mesophilic and permits to increase biogas production (8.6%) and methane content (9.3%). In turn, mesophilic fermentation has more stable pH changes in comparison with the thermophilic technology. However, it is related to inhibition of the propionic acid, which can be of great importance in case of continuous fermentation. On the basis of energetic calculations it was shown that the substitution of the maize silage with the maize straw silage allows for nearly three-fold costs reduction and thus increase of the biogas plant profitability.

In recent years, constructed wetland systems are used widely for the purification of small amounts of wastewater because they provide very high effects of removing impurities. The existing research results show that constructed wetland systems can be used not only for highly efficient wastewater treatment, but at the same time in order to produce biomass for energy purposes. The aim of this paper was to determine the possibilities of energy use of the plants: common reed, willow, Jerusalem artichoke, giant miscanthus, obtained from constructed wetland system. The yield of common reed was the highest compared to the other plant species used in analyzed object and amounted to 13.6 Mg DM ha −1 and then 8.7 Mg DM ha −1 for willow. The lowest dry matter yield was 5.9 Mg DM ha −1 in the case of Jerusalem artichoke. High Heating Value was similar in all analyzed plants (17.9–19.2 MJ kg −1 ), the highest results were obtained from willow. Biomethane production during anaerobic digestion was the highest from common reed (108 m 3 Mg −1 FM) and the lowest from Jerusalem artichoke (66 m 3 Mg −1 FM). The methane concentration in biogas was rather low (50.9–54.9) comparing to other typical substrates for biogas production.

The present paper reports pollutant removal efficiencies and reliability for a four-stage hybrid constructed wetland (HCW) consisting of the following sequence of subsurface (SS), vertical flow (VF) and horizontal flow (HF) beds: SSVF-SSHF-SSHF-SSVF. The experiments were carried out over a period of three years, with sampling done in each season: winter, spring, summer and autumn. Grab samples of wastewater collected from different stages of treatment were tested for total suspended solids (TSS), BOD5, COD, total nitrogen (TN) and total phosphorus (TP). The wetland was found to have a very high efficiency of removal of suspended solids and organics, with relatively little seasonal variability. The three-year average TSS removal efficiency was approximately 92.7%. The effectiveness of elimination of organic compounds was very high throughout the study period at 96.6% BOD5 and 95% COD. The effluent from the four-stage system had significantly lower contents of TN and TP compared to the wastewater discharged from the first two beds of this facility.

The hydraulic loading of biofilter (HL), temperature and C/N ratio - these factors influence on nitrogen and carbon removal efficiency from airport wastewater containing de-icing agents. The vast area of airports and significant fluctuations in atmospheric precipitation contribute to huge differences in wastewater flows discharged to treatment systems. The aim of the study was to determine the influence of the hydraulic loading on nitrogen and organic compounds removal in biofilters in low temperatures. The novelty of the paper results from low temperatures (0, 4 and 8 °C), specific wastewater and biofilter filling (light weight aggregates prepared from fly ashes from sewage sludge thermal treatment (FASST LWA). The study was divided into four series differing in the hydraulic loading (1.0, 3.0, 5.0, and 10.0 L·m−2·d−1). In each series, biofilters (filled with FASST LWA) were operated at the temperature of 0, 4, 8 °C and 25 °C. The organic carbon to nitrogen ratio was 0.5. The study showed the effective removal of nitrogen at low temperatures, even at high HL. The highest efficiency of nitrogen removal at the temperature of 0 °C (34.93 ± 4.54%) was obtained at 5.0 L·m−2·d−1. The hydraulic loading and temperature affected the efficiency of nitrogen and COD removal. The presented experiment demonstrated that the use of biofilters filled with FASST LWA may offer an effective and sustainable method for the treatment of airport de-icing wastewater.

This paper reports a comparative study on kinetics of organic matter expressed as BOD5 and nitrogen removal in constructed wetlands operated in Poland. Analyzed data were collected at eight wetland systems, composed of subsurface flow beds: horizontal flow (HF) and vertical flow (VF), in different number and sequences. The analysis involved particularly mass removal rates (MRR) and first-order removal rate coefficients of BOD5 and total nitrogen (kA and kv for VF and HF filters, respectively, and k20 as a parameter averaged for a temperature of 20 °C). It was found that the higher the load of pollutants applied to the beds, the higher MRR values were obtained. The average k-rates in analyzed systems were mostly lower than those reported in the literature, especially in the case of total nitrogen. Its removal obtained in horizontal flow beds was kv = 0.002–0.042 d−1, while in vertical flow systems kA varied from 0.007 m d−1 to 0.0037 m d−1. According to data given by previous studies, first-order reaction rates for nitrogen removal varied in range from kv = 0.048 d−1 to kv = 0.19 d−1 and kA from 0.007 to 0.1 m d−1 in HF and VF beds, respectively. Regarding BOD5 shown in literature, removal rate kv for HF beds varied from 0.071 to 6.11 d−1, and kA for VF beds varied from 0.019 to 1.0 m d−1, while in this study lower k-rates were obtained: kv = 0.005–0.085 d−1 and kA = 0.015–0.130 m d−1. Relatively long monitoring period, for some of constructed wetland up to 16 years, resulted in good data set and enables creation of the graphs, which could be helpful in evaluation and designing of constructed wetlands for PE bigger than 50, in moderate climate conditions.

The aim of this work was to determine the potential of phytoremediation of Vetiveria zizanioides and Oryza sativa to nitrate (NO3−-N) and organic matter (COD – chemical oxygen demand) removal in subsurface vertical flow constructed wetland systems (VFCWs). The tests were carried out in models of 2 beds with a surface of 0.24 m2 and depth 0.70 m each at various hydraulic loads (HL) and COD constant in influente wastewater. The VFCW-1 bed was planted with the Vetiveria zizanioides and the VFCW-2 bed with the Oryza sativa. During the 22 weeks of research, the hydraulic load of the analyzed beds was: HL1 = 148 dm3·m−2·d−1, HL2 = 239 dm3·m−2·d−1, HL3 = 350 dm3·m−2·d−1, HL4 = 473 dm3·m−2·d−1. The VFCWs were fed from two reservoirs, one with mineral medium and nitrate, and the other one with fructose as organic matter. Based on the conducted tests, it was found that in both analyzed systems (VFCW-1 and VFCW-2) the highest NO3−-N removal rate was found under HL2 – the median is 59 and 42% respectively. The most effective removal of COD in the VFCW-1 system was obtained at a HL2 – 55%, while in the system VFCW-2 at a HL1 – 43%. The research shows that the low HL and high COD/NO3−-N ratio ensures good effects of nitrate and organic matter removal in VF type constructed wetland systems. It has been shown that the analyzed plants, especially Vetiveria zizanioides have good phytoremediation potential in the field of nitrate nitrogen and organic substance removal and can be recommended for use on a full scale of technology.

The aim of the study was to evaluate the nitrogen removal and its effects on the plant’s growth and leaves morphology. using two subsurface vertical flow (VF bed), with different depths (0.24 m2 × 0.70 m; 0.24 m2 × 0.35 m) and nitrogen load increments. The VF bed were planted with Vetiveria zizanioides, filled with light expanded clay aggregates (Leca®NR 10/20) and fed in parallel mode with synthetic wastewater. High ammonium nitrogen concentration ([NH4 +–N] from 68 ± 3 to 290 ± 8 mg L−1) was used without toxicity symptoms in plants, although the effects of ammonium nitrogen load were stopped the growth of the plants. Significant differences between ammonium nitrogen removed in each VF bed obtained for total nitrogen (TNinfl.) ≥ 27 ± 0.8 g m−2 d−1. The nitrification was contributed to ammonium nitrogen removal because was found higher values of nitrate and nitrite in the effluent. These values were more higher in VF bed 1 than in the VF bed 2, since ammonium nitrogen removal were also more higher in VF bed 1 than in the VF bed 2. Total nitrogen mass balance was carried out and the results show that the nitrification/denitrification process occurred with nitrogen plants uptake. It was observed that the VF bed depth has an influence on all nitrogen removal processes. As higher the depth root system it is seemed to favour the creation of zones with different oxidations conditions that allow the nitrogen compounds to be removed intensively.

In this paper, the pollutant removal efficiency and the reliability of a vertical and horizontal flow hybrid constructed wetland (CW) planted with common reed, manna grass, and Virginia mallow were analyzed. The wastewater treatment plant, located in south-eastern Poland, treated domestic sewage at an average flow rate of 2.5 m3/d. The tests were carried out during five years of its operation (2014&ndash, 2018). The following parameters were measured: biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids, total nitrogen, and total phosphorus. The results showed that more than 95% of BOD5, COD, and total phosphorus was removed in the tested CW system. The average effectiveness of removal of total suspended solids and total nitrogen exceeded 86%. A reliability analysis performed using the Weibull probability model showed that the removal reliability in the tested CW was very high for BOD5, COD, total suspended solids, and total phosphorus (100%). The probability that the total nitrogen concentration in the treated effluents would reach the limit value (30 mg/L) established for effluents discharged from a treatment plant of less than 2000 PE (population equivalent) to standing waters was 94%. The values of all the pollution indicators in wastewater discharged to the receiver were significantly lower than the limit values required in Poland. The investigated hybrid CW system with common reed, manna grass, and Virginia mallow guaranteed stable low values of BOD5, COD, total suspended solids, and total phosphorus in the treated wastewater, which meant it was highly likely to be positively evaluated in case of an inspection.

The paper presents the results of a study of the efficiency and technological reliability of total nitrogen and total phosphorus removal during long term operation of a one-stage constructed wetland system with subsurface horizontal wastewater flow. The flow rate of the wastewater treatment plant was 1.2 m3/d during the research period. Physical and chemical analyses of raw wastewater and treated effluent were carried out in the years 1997–2010 (14 years). During this study period, 56 series of analyses were performed and 112 wastewater samples were collected. It was observed that the average efficiency of total nitrogen and total phosphorus removal amounted to 51% and 73%, respectively. The technological reliability, determined by means of the Weibull reliability method, was 45% for total nitrogen removal and 48% in the case of total phosphorus removal. Total nitrogen and total phosphorus concentrations in the treated wastewater did not exceed the permissible values in 39.3% and 37.5% of cases, respectively. A negative correlation was found between the sorption capacity of the soil-plant filter for the removal of total phosphorus and the time of plant operation. The efficiency of total nitrogen removal was stable over time.

The quality of surface water in watercourses in the region of Lublin agglomeration was studied in 2012–2014. Biological and chemical indicators of the study for various sampling sites were detected and the resulting values of the indicators were processed statistically. Rivers characterized by small size and the flow and modification of the riverbed. The resulting low values of macrophyte river index and infusorial index pointed to a poor quality of surface waters. Chemical indicators of the quality of surface waters reached low values, only BOD and phosphates reached high values. The river is located outside the city and it is characterized by moderate potential ecological (III quality class), and the river within Lublin is insufficiently potential ecological (IV quality class). Statistical analysis showed high variability index values between the studied positions.