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PL
Celem niniejszego artykułu jest przedstawienie problemów związanych z eksploatacją kotłów parowych o ciśnieniu roboczym do 20 barów. Szczególną uwagę zwrócono na wymagania jakości wody zasilającej kotły parowe, jak też problem odsalania oraz oszczędności wody i ciepła. Wskazano technologie uzdatniania wody, najbardziej opłacalne w zastosowaniu.
EN
The aim of this paper is to present problems connected with exploitation of steam boilers with pressure up to 20 bars. Particular emphasis is put on the quality of steam boiler feed water, on desalting problems, water and heat savings. Water treatment technologies are indicated, the most cost-effective in application.
PL
Celem niniejszego artykułu jest przedstawienie problemów związanych z eksploatacją kotłów parowych o ciśnieniu roboczym do 20 barów. Omówiono przyczyny wytrącania się osadów kamienia kotłowego i korozji. Szczególną uwagę zwrócono na wymagania dotyczące jakości wody zasilającej kotły parowe, jak też na problem odsalania oraz oszczędności wody i ciepła.
EN
The aim of this paper is to present problems connected with exploitation of steam boilers with pressure up to 20 bars. Reasons of boiler scaling and corrosion are described. Particular emphasis is put on the quality of steam boiler feed water, on desalting problems, water and heat savings.
EN
Purpose: Due to an increase in a number of bridges being constructed, scour depth around bridge piers is gradually being recognized as one of the possible reasons for bridge failure. According to [1] about 53% of bridge failures in the US were caused due to floods and corresponding scour in the rivers. Lots of work has been carried out around the single pier but in the case of group piers, the work is very less. Hence, it becomes necessary to calculate the actual scour depth around the bridge piers considering the close location of bridges as well. Design/methodology/approach: Recognizing the need for research in this direction, an experimental study was planned and conducted in the Hydraulics Laboratory of Civil Engineering Department of National Institute of Technology Kurukshetra, India. Experiments were conducted in a standard recirculating tilting bed water flume 15 m long, 0.4 m wide, and 0.60 m deep. The orientation of more than one pier, namely Tandem pattern was employed for the work. Two pier models, 62 mm and 42 mm diameter were used for the experimental study. The mobile bed used in the experiments had an average mean size, d50 = 0.23 mm, 0.30 mm and 0.50 mm. Findings: The outcomes of the ANN function and M5 model analysis have been used to compare with experimental results. From the earlier studies, it was concluded that, when the clear spacing between the pier models was greater than 0D the scour depth around the piers increase with a rapid rate. However, in the case of modelling techniques, M5 models show higher predictive accuracy than ANN models. Research limitations/implications: It is a significant area of research. However, the present study has been a time and facility- constrained study. Therefore, there is a large scope to conduct further studies on the subject, Different pattern i.e. Side by Side; Staggered and Group of piers can be adopted for further investigations. Originality/value: Sufficient work has been done by number of researchers around the single bridge pier. But due to rapid urbanization a number of bridges constructed in close proximity to each other which affects the scour depth of each other. Modelling techniques used in hydraulic engineering are not always effective in practice. The present study discusses the effect of spacing on scouring around piers in a tandem arrangement using experimental as well as modelling techniques. To predict the scour depth of the Tandem arrangement 89 laboratory data sets have been used.
EN
Throughout the world, considerable quantities of water treatment sludge (WTS) and sewage sludge (SS) are produced as waste. This study assessed in the laboratory, the possibility to use both waste products when they are incorporated as filler at 1% with relation to the total mass of a hot mix asphalt - HMA. To this end, both waste products were initially reduced to ash through a calcination process. Resistance tests under monotonic load (Marshall and indirect tension tests), and cyclic load (resilient modulus test) were applied on mixes that contained WTS and SS. Besides, moisture damage (modified Lotmman test), and abrasion (Cantabro) resistance were assessed. An analysis of variance (ANOVA) test was performed in order to verify if the results are statically equal or not to those of the control HMA. As a general conclusion, it is reported that both materials show a resistance increase under monotonic load and higher stiffness under cyclic load (cohesion) when they are incorporated into the mix as filler despite the fact that the asphalt content used was less than the control mix. However, some problems are observed associated with moisture damage resistance, and friction wear (adherence).
EN
This study investigated the multifractality of streamfow data of 192 stations located in 13 river basins in India using the multifractal detrended fuctuation analysis (MF-DFA). The streamfow datasets of diferent river basins displayed multifractality and long-term persistence with a mean exponent of 0.585. The streamfow records of Krishna basin displayed least persistence and that of Godavari basin displayed strongest multifractality and complexity. Subsequently, the streamfow-sediment links of fve major river basins were evaluated using the novel multifractal cross-correlation analysis (MFCCA) method of cross-correlation studies. The results showed that the joint persistence of streamfow and total suspended sediments (TSS) is approximately the mean of the persistence of individual series. The streamfow displayed higher persistence than TSS in 60% of the stations while in majority of stations of Godavari basin the trend was opposite. The annual cross-correlation is higher than seasonal cross-correlation in majority of stations but at these time scales strength of their association difers with river basin.
EN
The model reclamation process of the studied fly ash deposits has been started in 2003 by formation of five different experimental surface layers containing fly ash and organic matter in various combinations. Then, grass mixture was sown on these surface layers. In 2015, selected properties of plant communities growing on different variants of surface layers applied in the reclamation process were assessed. It was assumed that the type of mineral and organic substrates used in the process and their quality were the main factors affecting the long term plant diversity present on different variants of restored surfaces. The aim of this analysis was the assessment of the effectiveness of ash waste reclamation (carried out on five different types of the surface layer) after 12 years since its initiation. The long term results of the reclamation process showed that the applied surface layers allowed for an effective reclamation of ashes since all variants of experimental surfaces were totally covered by dense vegetation. The predominance of plant species from ruderal and segetal habitats indicated that the soil of the experimental habitats was fertile with neutral and slightly alkaline pH, and texture of sandy loams. The experimental surface layers with a texture of sand of favourable C:N ratio, neutral or slightly alkaline did not limit the plant development. The use of organic waste markedly contributed to the floristic diversity of the spontaneously developed vegetation. Coniferous bark used in some experimental variants had a marked effect on their floristic distinctiveness due to the presence of species preferring habitats of lower pH values.
EN
Composting of sewage sludge together with green waste such as grass, leaves, branches, etc. is carried out in Poland on many objects. A common problem of all exploiters is the selection of the type of composting technology and its modification to the conditions prevailing in a particular region because the waste, that given objects are exposed to, is different which makes it necessary to adapt the technology to the conditions prevailing in the given facility. In the field of technological research of the composting process, the expected effect of the research was the characteristics of conditions for composting organic waste in relation to the efficiency achieved, indication of the optimal technological parameters and assistance in the selection of the target composting technology. The waste composting technology is based on the appropriate selection of the composition of the prisms and the periodic transfer of the piles by means of a specialized turning machine. For the purpose of the study project, the following research problem was formulated: what is the intensity of the composting process depending on the technological parameters of the prism (the size of the prism, the types of waste), the properties of the waste, the intensity of aeration by turning? According to the above basis, the following research hypotheses were identified: − the intensity of composting decreases with the increase of the cubic capacity (height) of the prism, − the intensity of composting decreases with the decrease in the frequency of waste transfer, − the intensity of composting decreases as a result of the application of organic waste.
PL
Kompostowanie osadów ściekowych wraz z odpadami zielonymi takimi jak trawa, liście, gałęzie itp., prowadzona jest w Polsce na wielu obiektach. Wspólnym problemem wszystkich eksploatatorów jest wybór rodzaju technologii kompostowania oraz jej modyfikacja do warunków panujących w danym regionie, ponieważ odpady trafiające na poszczególne obiekty różnią się od siebie, co powoduje konieczność dopasowania technologii do warunków panujących na danym obiekcie. W zakresie badań technologicznych procesu kompostowania spodziewanym efektem badań była charakterystyka warunków prowadzenia kompostowania odpadów organicznych w relacji do uzyskiwanych efektywności, wskazanie optymalnych parametrów technologicznych oraz pomoc w doborze docelowej technologii kompostowania. Technologia kompostowania odpadów oparta jest na odpowiednim doborze składu pryzm oraz okresowym przerzucaniu pryzm za pomocą specjalistycznej przerzucarki. 60 Na potrzeby projektu badań sformułowano następujący problem badawczy: jaka jest intensywność procesu kompostowania w zależności od parametrów technologicznych pryzmy (wielkość pryzmy, rodzaje odpadów), właściwości odpadów, intensywności napowietrzania poprzez przerzucanie? Na tej podstawie zidentyfikowano następujące hipotezy badawcze: − intensywność kompostowania maleje wraz ze wzrostem kubatury (wysokości) pryzmy, − intensywność kompostowania maleje wraz ze spadkiem częstotliwości przerzucania odpadów, − intensywność kompostowania maleje w wyniku stosowania zagnitych odpadów organicznych.
EN
In the presented investigation, cold-rolled sheets of a selected dual-phase (DP) steel were heat-treated according to varying thermal profiles, thus reproducing continuous annealing process. Initially the samples were soaked at 780 and 810 °C for 0–60 s followed by water cooling. Next, samples were preliminary treated by applying the same conditions, however after water cooling these compositions were subject to tempering at 230, 380 and 460 °C for both 60 and 240 s. The characterization of the effect of heat-treatment parameters on the mechanical properties and structure is the main objective of this investigation. Mechanical properties of the samples after applied thermal profiles were in line with those requirements imposed on the commercial sheets of DP steels. The obtained results of the investigation showed that tempering deteriorates the Yield Ratio, defined as Rp0.2/Rm. This was caused by the martensite decomposition combined with carbide precipitation processes. Transmission electron microscopy observations revealed precipitated carbides, Fe3C in martensitic and M7C3 in ferritic areas. The quantitative results of the structural investigation were then applied to predict the Rp0.2 and Rm using the Perlade model. The results indicate that discrepancies between the measured tensile tests and calculated Rp0.2 and Rm do not exceed 10%.
EN
Biogas plants in Poland are currently one of the most profitable alternative energy sources. The high efficiency of the biogas plant is guaranteed first of all by the appropriate selection of heat exchangers inside the anaerobic digester. There is no data in the literature regarding the operation of heat exchangers used in an anaerobic digester. The sludge in the digester is often deposited on the tubes of the heat exchanger, thereby reducing the efficiency of the heat transfer which can lead to a dangerous temperature drop inside the digester. This paper discusses the influence of sludge on the operation of the heat exchanger in a biogas plant. In order to determine the heat transfer coefficient for the heat exchanger tubing flowing around, the correlations proposed by Churchill and Bernstein were adopted, while inside the heat exchanger tubing the heat transfer coefficient was calculated from the Dittus-Boelter correlation. The measured actual parameters of the biogas plant operation were used for the calculations. In the first issue, dependence of return temperature from the heat exchanger and thermal efficiency of the exchanger was determined depending on the thickness of the sludge layer and the thermal conductivity of the sludge. For the calculations a constant flow velocity of the substrate was assumed: 0.001 m/s and the following thermal conductivity of sludge were assumed: 0.3, 0.5 and 1,0 W/(mK). Along with the increase of the thickness of the sludge layer on the exchanger wall, the return temperature from the exchanger increases, which leads to a decrease in the thermal efficiency of the exchanger. In the second issue, the function of return temperature from the heat exchanger and thermal efficiency was determined depending on the substrate flow velocity and the thickness of the sludge layer. A constant unit thermal conductivity coefficient of the sludge and piping of the exchanger without sludge and sludge with the thickness of the sludge layer 0.005 m and 0.01 m were assumed for calculations. With the increase of the flow velocity, the return temperature from the exchanger decreases, while the thermal efficiency of the exchanger increases. The heat exchanger piping is installed close to the wall of the digester where the substrate flow rates are small. All calculation results are presented in the form of graphs. One of the ways to increase the thermal efficiency of the exchanger is to increase the supply temperature. It should be noted that too high temperature within the exchanger's piping can lead to the destruction of microorganisms in the fermentation chamber. The paper also presents measurements of energy consumption for heating the digester in 2015-2017. The amount of heat consumed to heat the fermentation chamber increased with the time of exploitation of the fermentation chamber as a result of the sludge accumulating on the fermentation chamber. The publication is supplemented with photographs showing deposits on the walls of the heat exchanger.
PL
Biogazownie w Polsce są obecnie jednym z najbardziej dochodowych alternatywnych źródeł energii. Wysoką wydajność biogazowni zapewnia przede wszystkim odpowiedni dobór wymienników ciepła w beztlenowej komorze fermentacyjnej. W literaturze brak jest danych dotyczących działania wymienników ciepła stosowanych w beztlenowej komorze fermentacyjnej. Osad w komorze fermentacyjnej często osadza się na rurach wymiennika ciepła, zmniejszając tym samym efektywność wymiany ciepła, co może prowadzić do niebezpiecznego spadku temperatury wewnątrz komory fermentacyjnej. W pracy omówiono wpływ osadu na pracę wymiennika ciepła w biogazowni. W celu wyznaczenia współczynnika przenikania ciepła dla opływanego poprzecznie orurowania wymiennika przyjęto korelacje zaproponowane przez Churchilla i Bernsteina, natomiast wewnątrz orurowania wymiennika ciepła współczynnik przejmowania ciepła obliczono z korelacji Dittusa-Boeltera. Do obliczeń przyjęto zmierzone, rzeczywiste parametry pracy biogazowni. W pierwszym zagadnieniu wyznaczono zależność temperatury na powrocie z wymiennika ciepła oraz wydajności cieplnej wymiennika w zależności do grubości warstwy osadu i współczynnika przewodzenia ciepła osadu. Do obliczeń przyjęto stałą prędkość opływu orurowania substratem: 0.001 m/s oraz następujące współczynniki przewodzenia ciepła osadu: 0.3, 0.5 oraz 1.0 W/(mK). Wraz ze wzrostem grubości warstwy osadu na ściance wymiennika temperatura na powrocie z wymiennika rośnie, co prowadzi do obniżenia wydajności cieplnej wymiennika. W drugim zagadnieniu wyznaczono funkcję temperatury na powrocie z wymiennika ciepła i wydajności cieplnej w zależności od prędkości przepływu substratu w obrębie orurowania wymiennika ciepła oraz od grubości warstwy osadu. Do obliczeń przyjęto stały jednostkowy współczynnik przewodzenia ciepła osadu oraz orurowanie wymiennika bez osadu i z osadem o grubości warstwy osadu 0.005 m i 0.01 m. Wraz ze wzrostem prędkości przepływu temperatura na powrocie z wymiennika maleje, natomiast wydajność cieplna wymiennika rośnie. Orurowanie wymiennika ciepła jest zainstalowane blisko ściany komory fermentacyjnej, gdzie prędkości przepływu substratu są niewielkie. Wszystkie rezultaty obliczeń zostały przedstawione w formie wykresów. Jednym ze sposobów zwiększenia wydajności cieplnej wymiennika jest zwiększenie temperatury zasilania. Należy tu zaznaczyć, że zbyt duża temperatura w obrębie orurowania wymiennika może doprowadzić do zniszczenia mikroorganizmów w komorze fermentacyjnej. W pracy przedstawiono również pomiary zużycia energii na cele ogrzania komory fermentacyjnej w latach 2015-2017. Ilości zużytego ciepła na cele ogrzania komory fermentacyjnej rosła wraz z czasem eksploatacji komory fermentacyjnej w wyniku gromadzącego się na komorze fermentacyjnej osadu. Publikację uzupełniają zdjęcia przedstawiające osady na ścianach wymiennika ciepła.
EN
The present work was designed to assess the contamination level in the coastal of Annaba, following the spectrophotometric determination of the level of some metallic elements (Fe, Cu, Pb, Zn, Ni and Cd) in the sediments along an increasing bathymetric gradient (10 m and 20 m), as well as in the biological indicator grey mullet (Mugil cephalus) muscle. During the winter period (2014), 12 surface sediment samples, and a total of 24 fish were collected. Once the samples are dried, crushed and sieved, 0.5 g dry weight of each sample was added to concentrated acids. The results showed that the levels of some metals are superior to the recommended guideline values, and consequently the sediment of this bay is contaminated by iron, lead and copper. The contamination index (CI) showed a general tendency in the concentration of the studied metals as follows: Fe > Pb > Cu > Zn > Ni > Cd, since the most studied metals occurred at higher concentration in depth (20 m). However, the average concentrations of metals in fishes were found to be as the following order: Fe > Zn > Pb > Cu > Ni > Cd. The consumption of fish from some contaminated sites can be dangerous because concentrations of lead, cadmium and zinc exceed the international standards. Moreover, the strong positive correlation observed between the metallic elements of sediments and fishes confirm that these metals resulted from the similar sources of the anthropic activities, such as domestic, port, industrial and agricultural waste discharges. This is confirmed by the determined of pollution load index (PLI) parameter. Conclusively, a regular monitoring program of heavy metal is recommended for protecting these organisms, and to reduce the environmental risks.
PL
W pracy oceniono poziom zanieczyszczenia strefy przybrzeżnej w okolicach Annaby na podstawie spektrofotometrycznych analiz metali (Fe, Cu, Pb, Zn, Ni and Cd) w osadach na różnej głębokości (10 i 20 m) i w mięśniach cefala pospolitego (Mugil cephalus) jako organizmu wskaźnikowego. W okresie zimowym (2014 r.) zebrano 12 próbek osadów powierzchniowych i łącznie 24 ryby. Po wysuszeniu, pokruszeniu i przesianiu próbek do stężonych kwasów dodano 0,5 g suchej masy każdej próbki. Wyniki dowodzą, że stężenie niektórych metali przekracza dopuszczalne normy, a osady w zatoce są zanieczyszczone żelazem, ołowiem i miedzią. Wskaźnik zanieczyszczenia (CI) kształtował się następująco: Fe > Pb > Cu > Zn > Ni > Cd, przy czym większe stężenie większości metali notowano na głębokości 20 m. Średnie stężenie metali w mięśniach ryb układało się natomiast w porządku: Fe > Zn > Pb > Cu > Ni > Cd. Konsumpcja ryb z niektórych skażonych stanowisk może być niebezpieczna, ponieważ stężenie ołowiu, kadmu i cynku przekracza międzynarodowe standardy. Ponadto, silna dodatnia korelacja między stężeniem metali w osadach i w rybach dowodzi, że metale te pochodzą z tych samych antropogenicznych źródeł takich jak zrzuty ścieków bytowych, portowych, przemysłowych i rolniczych. Potwierdza to oznaczony wskaźnik ładunku zanieczyszczeń (PLI). W podsumowaniu zaleca się wdrożenie regularnego programu monitoringu w celu ochrony organizmów wodnych i ograniczenia ryzyka środowiskowego.
EN
The continuity of sediment transport in many catchment-river-sea systems worldwide has been disturbed by anthropogenic interferences. These interferences alter the sediment balance and result either in a surplus or lack of sediment, and with mostly negative, impacts to the economy, development and infrastructure, and environment. The main issues discussed related to surplus or lack of sediment belongs to: i) siltation of reservoirs with negative effects on hydropower production or water storage, and ii) erosion at downstream reaches where sediments are essential for channel formation and aquatic habitats. Both problems are recognized in Poland, however, only dealt with when they cause local economic problems. The paper focuses on examples of sustainable sediment managements in catchment-river-sea systems, and presents the idea of combining the Macromodel DNS with the SWAT module. The resulting modelling and analytical tool can be considered very valuable in sediment quantity management.
14
Content available remote Analysis of the microstructure and properties of T92 steel after long-term service
EN
Purpose: The purpose of the investigation was to determine and analyse the changes in the microstructure and mechanical properties of the T92 steel after service in creep conditions of the following parameters: temperature – 575°C, pressure – 28.2 MPa, service time – 41914 hrs. Design/methodology/approach: The tests were performed on the test samples taken from a pipe section of a steam superheater after long-term service. The range of the investigations included: microstructural investigation – the optical and SEM microscopy, the analysis of precipitation – carbide isolates, the investigation of mechanical properties: the Vickers hardness measurement, the impact test and static tensile test. Findings: The performed tests showed a slight degree of exhaustion of the structure of the analysed T92 steel. The relatively small changes in the microstructure of the examined steel were reflected in the still retained high mechanical properties. Research limitations/implications: he analysis of the microstructure of the examined steel using SEM was performed to determine the influence of the service on the processes of changes in the precipitate morphology. Practical implications: The metal science investigation of the sections taken from the elements of the power installations after long-term service is one of the basic elements of building the data base of materials and their joints used in the power industry. The results obtained from the performed research constitute a building block for the degradation characteristics of the microstructure and mechanical properties of martensitic steels of the 9-12%Cr type. Originality/value: The results of investigation and analysis of the metallographic and mechanical properties of martensitic T92 steel after long-term service are presented.
EN
Baltic-type raised bog (dome-shaped) is a type of peatbog with predominant atmospheric water supply and a convex shape, known as the dome. In Poland, 72 Baltic peatbogs have been distinguished, with various degrees of transformation, in the coastal zone and lake districts of the South Baltic Sea. None of them has natural water conditions. Their common name indicates significant similarities due to water supply conditions. However, due to the differences in morphology, both primary and secondary (resulting from the different course and scale of anthropogenic transformations), they may be expected to show some variability within the subtype. The aim of the paper is to present the diversity of water-level fluctuations in degraded Baltic raised bogs. An attempt was made to answer the question how strong the diversity of fluctuations is, both within each object and between two objects situated close to each other. Moreover, speed and value of the response of water level to atmospheric precipitation were analysed. The spatial scope of the paper covers two Baltic raised bogs in the lower part of the Łeba River valley: Czarne Bagno and £ebskie Bagno. To answer the questions asked, the results of measurements of water level and precipitation on the peat bogs were used. The study found that both the bogs show high dynamics in the variation of groundwater level. Lowering of the water level on both peatlands has always been recorded in the summer months, whilst its increase, which lasted until spring, has been observed in autumn. The water retention amount and water level on the peatlands were influenced primarily by precipitation. Extreme meteorological conditions that make it less conspicuous is the variation resulting from factors such as location in different parts of the bog, or type of degradation.
PL
W artykule przedstawiono ocenę możliwości zastosowania osadów zawierających żelazo, pochodzących z oczyszczania wody, jako zamiennika części wsadu rudnego w procesie spiekania rud żelaza. Przeprowadzono laboratoryjne próby spiekania, z udziałem do 5% osadów z oczyszczania wody w mieszance spiekalniczej. Stwierdzono, że wraz ze wzrostem udziału osadów w mieszance spiekalniczej pogarsza się jej przewiewność, a w konsekwencji wydajność procesu. Udział osadów z oczyszczania wody w mieszance spiekalniczej nie powinien przekraczać 1% mas.
EN
This article presents the assessment of the possibility to use iron-containing sediments derived from a water purification as a replacement for the part of ore load in the iron ore sintering process. Laboratory sintering experiments were carried out, with up to 5% of sediments in the sintering mix. It was found that with the increase in the proportion of sediments in the sinter mix, the decrease of the permeability of sinter mix occurs and as a consequence, the process productivity decreases. The share of sediments of the water purification in the sinter mix should not exceed 1 wt.%.
EN
The ballast water treatment systems are installed on vessels according to International Maritime Organization (IMO) and other marine administrations requirements. The aim is to minimize the risk of environment contamination from ships’ ballast water and sediments. The International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM 2004 Convention) is adopted in 2004 to introduce global regulations to control to transfer potentially invasive species. The BWM Convention will enter into force on 8th September 2017 on vessels with small exceptions. It was discussed the ballast water treatment standards and technology for fulfilment of IMO, EMSA, USCG and other regulations. The standard D-2 of ballast water cleanliness should be reached after proper treatment through the BWMS. Some BWMS packs were presented with their advantages and disadvantages. The existing problem is the ballast water cleanliness discharged outboard and the state of cleanliness of ballast water tanks and installation. It was mentioned some problems to solve during the choice of BWMS. It was discussed the threats for BWMS effectiveness of ballast water cleanliness.
18
EN
These studies examined the concept of concentration and purification of several types of wastewater by freezing and thawing. The experiments demonstrated that freezing of contaminated liquid contributed to concentration of contaminants in solution as well as significant concentration and agglomeration of solid particles. A high degree of purification was achieved for many parameters. The results of comparative laboratory tests for single and multiple freezing are presented. It was found that there was a higher degree of concentration of pollutants in wastewater frozen as man-made snow than in bulk ice. Furthermore, the hypothesis that long storage time of liquid as snow and sufficient temperature gradient metamorphism allows for high efficiency of the concentration process was confirmed. It was reported that the first 30% of the melted liquid volume contained over 90% of all impurities. It gives great opportunities to use this method to concentrate pollutants. The results revealed that the application of this process in full scale is possible. Significant agglomeration of solid particles was also noted. Tests with clay slurry showed that repeated freezing and thawing processes significantly improve the characteristics of slurry for sedimentation and filtration.
PL
Węglowodory ropopochodne należą do związków niebezpiecznych dla środowiska. W oparciu o istniejące normy PN-EN 14039:2008 oraz PN-EN ISO 16703:2011 opracowano szybką i tanią metodę oznaczania węglowodorów C10-C40 w próbkach gleby, osadów dennych, osadów ściekowych i odpadów techniką chromatografii gazowej z detektorem płomieniowo-jonizacyjnym (GC-FID). W celu wyznaczenia optymalnych czynników wpływających na wydajność ekstrakcji porównano ekstrakcję z wykorzystaniem mechanicznego wytrząsania z ekstrakcją wspomaganą ultradźwiękami. Dodatkowo optymalizacji poddano etap oczyszczania ekstraktu, doboru odpowiedniego rozpuszczalnika do izolacji analitów oraz wyznaczono warunki programu temperaturowego. W rezultacie ustalono optymalne warunki dla głównych etapów metody, które wpływają na wyniki oznaczeń węglowodorów C10-C40 w próbkach stałych. Dokładność metody została zweryfikowana poprzez analizę materiału odniesienia (TPH-Sandy Loam, RTC) oraz materiałów z dodatkiem wzorca (DE RIV-1, Mineraloil Standard RIV-1). Uzyskano odpowiednią selektywność i czułość do oznaczania węglowodorów ropopochodnych w próbkach stałych.
EN
Petroleum hydrocarbons are dangerous for the environment. Based on the existing standards PN-EN 14039:2008 and PN-EN ISO 16703:2011, a fast and cheap method has been developed for the determination of C10-C40 hydrocarbons in soil, sediments, sewage sludge and waste samples by gas chromatography with flame ionisation detector (GC-FID). In order to determine the main factors influencing the extraction efficiencies, a mechanical shaking extraction was compared with ultrasonic bath extraction. In addition, the optimization of a clean-up step, the selection of the appropriate solvent for the analytes isolation and the temperature program were applied. As a result, the optimum working conditions of the main stages were selected for the determination of C10-C40 hydrocarbons in solid samples. The accuracy of the method was verified by analysing reference material (TPH-Sandy Loam, RTC) and materials with oil standard (DE RIV-1, Mineraloil Standard RIV-1). The selectivity and sensitivity were suitable for the determination of petroleum hydrocarbons in solid samples.
EN
In this study to identify the flow pattern and local scour mechanism around pile groups, the flow field was simulated using FLOW-3D software. A pair of pile on a flat-bed channel with side by side and tandem arrangements was investigated. To establish Navier–Stokes equations, the RNGk-ε turbulence model was used and the results were verified using experimental data. In case of FLOW-3D capability, it was found that the software was able to properly simulate the expected interaction between the pile groups. The results of flow field simulation showed that Reynolds number and the pile spacing are the most influential variables in forming vortices. The flow around tandem pile and the downward flow around wake vortices were more intense and complicate in comparison with side by side arrangements and single pile.
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