Search

Applying green infrastructure measures helps to retain water in the land during wet periods, which in turn makes it more available during periods of drought. Water retention reduces the volume of rainwater that transforms into surface runoff, allowing for the increase in the intensity of evapotranspiration and infiltration, which helps to establish a catchment with a balanced hydrologic cycle that's effectively more resistant to the consequences of climate change. With increasing popularity of introducing low impact development (LID) solutions in highly urbanised catchments characterised by a high runoff coefficient, it is important also to reduce rainwater runoff in residential areas with lower density of housing. This work presents a numerical assessment of green infrastructure (green roofs, raingardens, permeable paving and rainwater harvesting) performance in increasing retention in a catchment area consisting of single-family houses. The numerical model of potential residency in Ożarów, Poland was developed in SWMM 5.2. software, replicating local conditions with input infiltration data collected through on site and laboratory testing, as well as data gathered during a period of registering local evaporation and precipitation conditions. After running a series of simulations of three rain events, varying in their duration and intensity, the model was enhanced with green infrastructure solutions by the utilisation of LID Controls option in SWMM. With rainfall simulations resulting in varying rainwater outflow hydrographs and with differences in the volume of collected rainwater outflow, the results of LID application were consistent with the reduction of the peak rainwater outflow (reduction rate 61.90-67.99%), as well as the decrease in rainwater outflow volume (reduction rate 61.17-62.12%). This research promotes the hydrologic effectiveness of introducing green infrastructure in low density housing establishments. [ABSTRACT FROM AUTHOR]

This paper presents a numerical assessment of the influence of green roofs applied in the urbanized catchment on the rainwater outflow hygrogram as well as costs and economic efficiency analysis of the proposed green architecture application. The campus basin of the Lublin University of Technology, Poland, was selected as the object of the study. Three variants of extensive green roof applications were designed. The numerical model of surface runoff was developed in US EPA's SWMM 5.2 software. The simulations were performed for three different rainfall events of various intensities and durations. The cost efficiency of the proposed green architecture was assessed by the Dynamic Generation Costs indicator, while economic effectiveness was tested by Benefits–Costs Ratio and Payback Period determined for all assumed variants. The determination of economic efficiency indicators was based on investment and maintenance costs estimation, assumed discount rate, and time duration of assessment. Results of numerical calculations showed up to 16.81% of peak flow and 25.20% of runoff volume reduction possibly due to the green roof application. All proposed variants of green roof applications in the studied urbanized catchment were assessed as generally profitable due to possible financial benefits related to heating and cooling energy savings and avoiding periodical change of bitumen roof cover. [ABSTRACT FROM AUTHOR]

This paper presents results of laboratory and numerical research concerning determination of water flow resistance through three types of two-way connection of polymer installation pipes: PP-R 20x3.4 mm and PEX/Al/PEX 16x2.0 mm. The following fittings were applied: the direct connection, pipe union and coupler, allowing to test six measurement variants. The laboratory measurements of pressure loss for the tested pipes connections were performed for variable Reynolds number, from approx. 5000 to 50000. The numerical modeling allowing to assess the distributions of velocity of flow and turbulence intensity were performed using FLUENT, Ansys Inc. modelling software. The relations between determined values of minor pressure loss and coefficients of local pressure losses and type of pipes connection, direction of flow as well as the value of Reynolds number were observed. The applied nonparametric statistics, combined with multi comparison, showed that in most cases of analyzed connections, besides the pipe union, the observed differences in pressure losses for various directions of flows are statistically significant for p = 0.05.

The assessment of the ratio of self-purification processes in the natural environment, including the water bodies of streams and rivers is possible by the means of the numerical modelling. Nonetheless, the reliability of results of the qualitative numerical calculations may be affected by the quality of the collected input data and efficiency of the model calibration. The commonly required input data include pollutants characteristics and coefficients for empirical equations of their transport and decay, while calibration of a model requires series of measurements of selected pollutants concentration in water. This paper presents studies of concentration of pollutants measured in the treated sanitary wastewater discharged to the Bystrzyca river from municipal wastewater treatment plant, and their concentrations measured directly in the river, above and below the location of discharge point. The performed qualitative measurements of treated sewage discharged from municipal wastewater treatment plant and water of the Bystrzyca river included determination of COD, BOD5, N-NH4, N-NO2, N-NNO3, TKN, TN, TP and TSS concentration. The presented results of measurements are the first step in development and calibration of the model, allowing to successfully predict the influence of discharged sanitary wastewater on quality of water in the river.

This paper presents an attempt to numerical modelling of water seepage through the connection of two concrete pipes, commonly used in the past in construction of sanitary and stormwater sewerage systems, sealed by three types of different cement-based mortars. The 2D numerical calculations were made by means of the commercial modelling software FEFLOW, WASY-DHI, especially popular in soil and environmental science. The required input data for the developed numerical model, including saturated hydraulic conductivity and retention characteristics of tested mortars, were obtained during the conducted laboratory measurements. The hydraulic characteristics of the applied concrete pipe were based on literature. The assumed boundary conditions reflected the concrete sewerage pipe filled by water to the height of 10 cm and the matric suction pressure of soil below the sand bed. Our numerical calculations showed diversified seepage intensity and accumulated volume of percolating water for the three tested mortars. The observed differences were in our opinion related to sand/cement ratio of each mortar. The higher sand content, the higher volume of seepage was noted.

Analysis of free chlorine propagation in water supply network has a significant meaning for the process of water distribution. Results of numerical studies allow the proper selection of disinfectant or suitable monitoring of pipelines endangered by stagnation of water. The first-order reaction of chlorine decay in pipe boundary layer and inside the waterbody is commonly successfully assumed in numerical modeling. The aim of this studies was to analyze transport of chlorine inside the rural water supply system. The calculations were performed with application of Epanet 2.0 with assumed the first-order re action of chlorine decay and empirically determined chlorine decay rate in the mass of waterbody. The periodical disinfection of water in the network with the constant chlorine concentration 0.3 mg·dm-3 introduced during the whole time duration of simulation was assumed to calculations. The obtained results of chlorine distribution showed that even after 4 days there were available pipelines in which concentration of free chlorine was lower than 0.2 mg·dm-3. Thus, the microbiological protection of water quality is unavailable in these pipelines.

Presented studies covered determination of minor pressure losses and values of minor loss coefficients for two selected installation valves: water control globe valve and angle valve, both DN 15. The tested valves were installed on three pipes, including PP 20x3.4 mm, PEX-Al-PEX 16x2.0 mm and Cu 15x1.0 mm. In order to reflect the real operating conditions of the angle valve, the elastic PVC pipe was used. Our researches were performed on the laboratory installation, for the variable flow rate. The obtained results of laboratory studies showed the clear dependence between minor pressure loss and minor loss coefficients of studied valves, and water flow rate (Reynolds number), degree of valves’ closure and, in some cases, manner of valves installation and material of pipes. The greatest values of minor pressure loss coefficients, of mean values relevantly statistically grater, were determined for the tested valves installed on the PEX-Al-PEX pipeline.

This paper presents laboratory and modelling studies of antioxidant butylated hydroxytoluene leaching from a water supply PE-HD pipe for laminar and turbulent flow. The reaction of BHT oxidation to BHT-OH was included in our calculations. Required input data, initial and boundary conditions were based on laboratory measurements performed for a new PE-HD pipe. Laboratory measurements covered tests of BHT content and homogeneity in pipe material as well as measurements of BHT concentration in water flowing inside the pipe loop with different velocities. The BHT content of the PE-HD pipe and its concentration in water were determined by GC-MS method. Modelling calculations of BHT concentration in water for two different types of flow were performed using the commercial CDF software Fluent (Ansys Inc.). Non-homogeneous BHT distribution in pipe material and leaching of the antioxidant to the water were observed during laboratory tests. Numerical prediction of BHT concentration in water showed acceptable agreement between measured and calculated data. Nonetheless, the universality of the developed model is limited by the great diversity of available plastic pipe materials with various contents and technological amendments.

Solid-state thermoelectric elements, such as thermoelectric (TE) modules, can be used as cooling devices. Small-sized TE modules, characterized by: lack of moving parts, no required refrigerants application as well as variable possible installation and operation positions, allow, in several specified cases, achieving the advantage in cooling process over the conventional refrigeration devices. This paper presents the results of the preliminary numerical determination of energetic efficiency of thermoelectric cooling system, applied for cooling a small-scale experimental room. The heat exchangers used in the cooling system consisted of heat sinks and radiators installed on the both sides of the TE module. The numerical assessment included in this paper, based on a 3D model reflecting the experimental room and thermoelectric cooling system, allowed determining the relation between TE module power supply characteristics and cooling effects, as well as time-related temperature distribution inside the modeled experimental room. The commercial modeling software FLUENT, ANSYS 12.0 by ANSYS Inc. was applied in numerical calculations. The results of the performed laboratory studies were used as a basis for model development, required input data, initial and boundary conditions. The results of laboratory tests showed the influence of amperage of power supply on the efficiency of cooling characteristics, as well as distribution of air temperature inside the experimental room. Calibration and validation of the developed model was also based on the results of laboratory experiment. The obtained results of numerical calculations showed the influence of amperage of power supply on efficiency of cooling characteristics as well as distribution of air temperature inside the experimental room. [ABSTRACT FROM AUTHOR]

The use of modern methods as well as modeling and simulation tools in the design of bioreactors allows for the analysis of the flow phenomena in a short period of time without the need of physical model preparation, and thus for the optimization of existing solutions. The article presents the simulations of the aeration process in an SBR-type bioreactor, realized by means of computational fluid dynamics (CFD) and ANSYS 12.1 software. The subject of the analysis was a diffuser of own design. The Design Modeler 12.1 module was used for the preparation of geometry representing the analyzed design, and the discretization of the continuous domain was carried out with the ANSYS Meshing 12.1 tool. The ANSYS Fluent 6.3 solver was used For model calculations. On the basis of the results obtained from the conducted simulations, it is possible to predict the parameters which will increase efficiency and effectiveness without the need to build a real set of prototype models of aeration systems. The results obtained indicate that an increase in the aeration velocity results in a decrease in the minimum Y-axis velocity for both the mixture and air. The observed differences are caused by the shape of the geometric model and the velocity of the air outlet through the openings, which affects the hydraulic process in the chamber. These processes affect both the amount of oxygen dissolved in the bioreactor and the behavior of the suspension in volume. The turbulence intensity during the aeration process is concerned mainly in the range from 3.9 to 8.7% and is comparable with the average values of turbulence degree obtained by other researchers. The air bubble diameter ranged from 0.3 to 4.5 mm, in the case of aeration velocity 5.68 cm/s, a significant part of the chamber were air bubbles with a diameter of 2.6 to 3.9 mm, i.e. they were not the limit values. [ABSTRACT FROM AUTHOR]

Chlorination of water belongs to the basic methods of its disinfection and is commonly used, permanently or periodically, as the final stage of water treatment in many water treatment stations in Poland. Although, the chlorination process is a well-known phenomenon, the selection of an appropriate dose of disinfectant is still a difficult task. The lack of chlorine in the water or its excessively low content (below 0.2 mg dm-3) may result in the lack of microbiological protection of water flowing through the pipes. A reverse situation is also unfavourable. The use of too high doses of chlorine at the entrance to the network, on the one hand, ensures adequate disinfectant concentration even in the fittings of the network, on the other hand, it can lead to dangerous for health disinfection by-products (DBPs) including trihalomethanes (THMs). The selection of the proper dose of chlorine should take into account factors affecting its consumption, chemical parameters of water as well as hydraulic parameters of water transport. Such possibilities are available due to application of numerical modelling to study the transport of chlorine in water. The aim of the presented research is to analyse the effectiveness of chlorination of water in a selected water supply network. Simulation tests were carried out for the various doses of disinfectant supplied to the network for the assumed duration of the simulation - 168 hours. The qualitative model was developed in the Epanet 2.0 software using a hydraulic model of the tested network. The first order chlorine decay reaction was assumed to modelling studies, with applied literature values of decay rate of chlorine in water. The results of simulation tests of chlorine transport in the network revealed difficulties in choosing the right dose of chlorine necessary to ensure microbiological protection of water in the network. The forced flow allowed effective disinfection of water. [ABSTRACT FROM AUTHOR]

Copyright of Ecological Chemistry & Engineering A is the property of Society of Ecological Chemistry & Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ecological Chemistry & Engineering A is the property of Society of Ecological Chemistry & Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the research that is presented in this paper was to evaluate the physical and mechanical properties of heat-insulating mortars with expanded cork aggregates and different binders. In this work, the measurements of surface roughness and adhesion strength, supported by determination of basic mechanical and physical parameters, such as density, bulk density, open porosity, total porosity, absorbability, thermal conductivity coefficient, compressive strength, flexural strength, and frost resistance of mortars containing expanded oak cork, were performed. The scanning electron microscope (SEM) investigations demonstrated the microstructure, contact zone, and distribution of pores in the heat-insulating mortars containing expanded cork. The results indicated that the addition of expanded cork and different binders in heat-insulating mortars triggers changes in their roughness and adhesion strength. The SEM research confirmed the very good adhesion of the paste to the cork aggregate. [ABSTRACT FROM AUTHOR]

This paper discusses the role of sustainable landfilling of municipal waste in the current systems of municipal waste management systems as the manner of final disposal of wastes. The actual data considering share of landfilling as final waste disposal in various countries all over the world allowed to asses importance of this method. Special attention was paid to sustainable landfilling in developing or undeveloped courtiers of low economic incomes. Then, the paradigm of sustainable landfilling was presented and the most effective methods of landfill isolation by liners were discussed. The compacted clay liners were presented as the gainful option for the developing countries. The main determinants of the compacted clay liners' long-term liner sustainability were described as hydraulic conductivity, swell-shrinkage properties and, finally, ability of soil/substrate to sustain its hydraulic conductivity after cyclic drying and rewetting. Finally, possible application of low plasticity clays instead materials of high plasticity, prone to shrinking and swelling, to construction of sustainable compacted earthen liner was underlined. [ABSTRACT FROM AUTHOR]

This paper presents results of the studies of ciliate assemblage in benthos of lowland river influenced by sewage discharged from the municipal wastewater treatment plant. During the presented research the 47 ciliate species, including 45 species from the benthos of the river and 18 from the activated sludge of aeration chamber were identified. Only two species registered in the activated sludge were not observed in the river. Against the background of the lowest number of species in the point located in the distance of 50 m below the discharge of sewage the maximum amount and biomass of these species were observed. Whereas, 200 m below the discharge the decrease in number and biomass of ciliate to the level noted for location before the discharge was observed. Thus, generalizing, one may state that influence of municipal WWTP sewage discharge for ciliate assemblage in the river's benthos was clearly visible but local. [ABSTRACT FROM AUTHOR]

Migration of organic substrates from polymer pipelines to tap water may result in deterioration of organoleptic water properties, especially its odor and flavor. The aim of the presented studies was to determine the threshold odor number (TON) and threshold flavor number (TFN) for water after its contact with plastic water supply pipelines. Unplasticized polyvinyl chloride PVC-U (33.4 mm × 2.2 mm), high density polyethylene PE-HD (32 mm × 2.4 mm) and cross-linked polyethylene PEX-b (28.6 mm × 3.2 mm) were selected for studies. The analysis procedure covered pipe sample flushing with ultra pure water for 1 hour, sample storage in ultra pure water for 24 hours at 23 °C, test for contaminant migration within 72 h (according to EN 1420-1:1999), dilution, and TON and TFN assessment by the complete and even method of the unforced choice (according to EN 1622:2006). The odor and flavor testing team consisted of 5 individuals, the measurements were repeated 3 times. The average calculated TON was in the range of 3-5 while TFN - 3-6. The highest value was observed for PE-HD and the lowest for PVC-U. Our studies demonstrated that PE-HD had the highest influence on organoleptic properties of water among the analyzed polymer materials, while the lowest influence was observed for PVC-U. [ABSTRACT FROM AUTHOR]

This paper presents the attempt of sustainable development assessment for one of the poorest regions of the European Union (EU), Lublin Voivodeship in Poland, during its first decade in the EU, i.e. 2004-2013. Our analyses, performed for all pillars of sustainability: social, economic and environmental-technical, were based on sustainable development indicators (SDIs). The set of 21 sustainable development indicators, based on freely available statistical data, was proposed in this paper. The SDIs for Lublin Voivodeship were compared to values for Poland and the European Union. The special attention was put to assessment of sustainable development diversification between urbanized and rural areas of Poland and Lublin province. Our analyses showed than both, Poland and Lublin Voivodeship, clearly developed during the last decade but their sustainable development is still endangered and slowed down by several causes. Moreover, the value of most tested sustainability indicators was significantly below the European mean. [ABSTRACT FROM AUTHOR]

Pipe tanks represent important runoff retention elements of urban stormwater systems. They enable us to reduce and retain runoff as well as to mitigate peak flows in the network. Pipe tanks are often taken into account while designing the spatial plan of urban catchment areas. Hence, there is a need to develop a relatively quick and accurate method for pipe tank dimensioning. A graphical–analytical method of designing a pipe tank is presented in the paper. In the assumed methodology, the possibility of employing machine learning for obtaining a more precise error prediction of the proposed pipe tank design method (compared with the tank volume simulations using the storm water management model (SWMM)) are considered. Thus far, this aspect has not been discussed in the literature. In the adopted calculation methodology, sensitivity analysis constitutes an important element, enabling us to assess the influence of the input data assumed for tank design on the dimensions of the outflow devices and the length of the retention chamber. [ABSTRACT FROM AUTHOR]

The aim of the research presented in this paper is to evaluate the feasibility of using hydrophobic agents based on organosilicon compounds for surface protection of lightweight concrete modified with waste polystyrene. The experimental part pertains to the physical and mechanical properties of polystyrene-modified lightweight concrete. The concrete samples were prepared with the following ingredients: CEM I 42.5 R cement, recycled polystyrene (0–2 mm), quartz sand (0–2 mm), coarse river aggregate (2–16 mm), and water. Silane and tetramethoxysilane were employed for surface hydrophobization. Concrete with 20% polystyrene exhibits high porosity (25.22%), which is related to an increase in absorptivity (14.75%) compared to the reference concrete. The hydrophobized concrete is characterized by the lowest surface free energy (SFE) value, which is 7 or 11 times lower than the value of reference concrete, depending on the agents. The test on the contact angle (CA) was performed before and after the frost-resistance test (F–T test). Lower SFE translates into lower adhesive properties, higher resistance of the material to the infiltration of water and corrosive compounds, e.g., salts, and higher resistance to freezing and thawing cycles. Silane and tetramethoxysilane coating raised frost resistance by 54–58% compared to the reference samples. This agent reduced absorptivity by 30%. Recycled polystyrene can be successfully used to produce lightweight concrete (LC) with high durability provided by hydrophobic/icephobic coatings. [ABSTRACT FROM AUTHOR]

In the presented paper, a study of bi-axial buckling of the laminated composite plate with mass variation through the cutout and additional mass is carried out using the improved shear deformation theory (ISDT). The ISDT mathematical model employs a cubic variation of thickness co-ordinates in the displacement field. A realistic parabolic distribution of transverse shear strains through the plate thickness is assumed and the use of shear correction factor is avoided. A C° finite element formulation of the mathematical model is developed to analyze the buckling behavior of laminated composite plate with cutout and additional mass. As no results based on ISDT for the considered problem of bi-axial buckling of the laminated composite plate with mass variation are available in the literature, the obtained results are validated with the data available for a laminated composite plate without cutout and additional mass. Novel results are obtained by varying geometry, boundary conditions and ply orientations. [ABSTRACT FROM AUTHOR]