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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 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 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 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.

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 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 work aims to examine and discuss the fertilizing properties of digestate (digested pulp) from three different agricultural biogas plants in terms of the substrates used. Based on the market prices of fertilizers, the economic value of the digestate has been assessed. For a selected biogas plant, the economic balance has been calculated, taking into account the income resulting from the sale of the digestate. The results obtained allow for stating that samples of digestate were rich in nitrogen (up to 6.58 g kg−1), and potassium (up to 16.3 g kg−1) in fresh matter (FM). The value of the digestate for installations was estimated in the range of 6.08–15.36 EUR·Mg−1. The analysis for one of the 1 MW biogas plants shows that under current conditions of supporting systems, the daily income for a biogas plant is 1,414 EUR and the digestate produced is worth another 334.4 EUR. Its application, especially on fields adjacent to biogas plants, is part of the principle of nutrient recovery in the circular economy.

The paper presents preliminary results of a study on the application of the SCD Probiotics Technology to improve surface water quality. The Technology is based on the principles of the effective microorganism (EM) technology developed in Japan over thirty years ago by Dr Teuro Higa. The study was carried out in 2006–2008 in a pond with an area of 1200 m2, receiving purified sewage discharged from a constructed wetland system with willow vegetation filter, in operation since 1994, to which the SCD Probiotics Technology was applied since September 2007 till June 2008. A decrease of biogens concentrations in the pond water was recorded after applying the tested technology – ammonium nitrate concentration decreased by 85.2%, total nitrogen by 56.9%, while total phosphorus by 77.6%. Chlorophyll a level also showed a decreasing tendency. However, more detailed studies are still required to confirm the effectiveness of the SCD Probiotics technology in the purification of surface water.

This paper presents a review of information about the method of sewage purification by constructed wetland systems (CWs) and the results of the efficiency of pollution removal in such systems. Data from various countries of the world indicate that single-stage CWs are characterised by a fairly high, above 80%, efficiency of removal of total suspended solids and reduction of BOD5 and COD, but lower efficiency of removing biogenic compounds – below 50%. Significantly higher efficiency of removing pollutants can be achieved with the use of multi-stage hybrid CWs whose efficiency in total nitrogen removal is from 61 to 86%, and of total phosphorus 70–99%. The results obtained indicate that the application of CWs may provide effective protection of water resources against pollution.