Wyniki wyszukiwania - Biblioteka Nauki

1

Hydraulic Conductivity and Porosity of Hardening Slurries with Fluidal Fly Ashes in Chemically Aggressive Environments

100%

Falaciński P. , Kledyński Z.

Archives of Hydro-Engineering and Environmental Mechanics

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2008

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tom Vol. 55, nr 3-4

65-81

EN

The article presents the results of hydraulic conductivity and porosity tests of hardening slurries prepared from Portland cement, betonite, water and fluidal fly ashes from combustion of hard and brown coal. In addition, the ashes were in two states of activation: non-activated and mechanically activated. The slurries were exposed to persistent, 160-day filtration of chemically aggressive liquids: distilled water, 0.5% solution of nitric acid and 1% solution of sodium sulphate. A comparative base was composed of samples exposed to filtration of tap water. The research was into relations between hydraulic conductivity and parameters characterizing the porosity structures in slurries, as well as into the influence of sample maturation periods, the state of activation and type of ashes, and the type of aggressive medium on porosity and conductivity of the material. The observed phenomena were typical of materials based on cement binders, and exposed to chemical aggression, e.g. sealing-up of porosity structures in response to sulphate corrosion and de-sealing in response to leaching corrosion, along with effects specific for slurries, such as a decrease of hydraulic conductivity in response to nitric acid solution. A favourable effect of fluidal fly ashes from brown coal was also noted.

2

Zagadnienie określania współczynnika wodoprzepuzczalności gruntów spoistych

100%

Wacławski M. , Gwóźdź R. , Wawok M.

Czasopismo Techniczne. Środowisko

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2005

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tom R. 102, z. 16-Ś

165--172

PL

W niniejszym artykule przedstawiono analizę wybranych metod wyznaczania i interpretacji wyników podczas określania współczynnika wodoprzepuszczalności gruntów spoistych. Wnioski oparto na wynikach badań laboratoryjnych przeprowadzonych z zastosowaniem aparatu trójosiowego ściskania i edometru.

EN

In the article present describe the analysis of the marking methods and the interpretations’ results for the coefficient of permeability in cohesion soils. The conclusion was based on the results of the laboratory testting in a triaxial pressure apparatus and an edometer.

3

Laboratory investigation of self-healing properties on geosynthetic clay liners with flaw

100%

Zhang G.-W. , Zhang H.-Y. , Wang J.-F. , Zhou L. , Liu P. , Jiang X.

Archives of Environmental Protection

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2015

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tom Vol. 41, no. 1

53--58

EN

The objective of this paper is to evaluate the self- healing properties of a commercially-available geosynthetic clay liner (GCL) using flexible-wall permeameter. The GCLs are produced by the same factory, but the contents of bentonite are different. Also the hydraulic conductivities (HC) of GCLs with no defect are different. In this study, specimens were completely saturated under the backpressure of 20 kPa before the test. Permeability tests were performed on GCL specimens with penet rating flaw and also on specimens permeated with distilled water and CaCl2 solutions. The test results were presented and discussed. Experimental results showed that the GCL with penetrating flaw did not exhibit complete self-healing in the case of flaw. After 120 days, the hydraulic conductivity increased by approximately an order of magnitude. In addition, CaCl2 solutions had a significant influence on the hydraulic conductivity. The research findings might be of interest to researchers and engineers who design liners for landfills and other liquid containment facilities.

4

Application of genetic algorithms for the estimation of hydraulic conductivity

100%

Bartlewska-Urban M. , Strzelecki T.

Studia Geotechnica et Mechanica

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2018

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tom Vol. 40, nr 2

140--146

EN

In the study described here model calibration was performed employing the inverse analysis using genetic algorithms (GA). The objective of analysis is to determine value of the coefficient of hydraulic conductivity, k. The commonly used method for the determination of coefficient of hydraulic conductivity based on Terzaghi consolidation leads to an underestimation of the value of k as the Terzaghi model does not take into account the deformation of soil skeleton. Here, an alternative methodology based on genetic algorithms is presented for the determination of the basic parameters of Biot consolidation model. It has been demonstrated that genetic algorithms are a highly effective tool enabling automatic calibration based on simple rules. The values of the coefficient of hydraulic conductivity obtained with GA are of at least one order smaller than values obtained with the Terzaghi model.

5

An assessment of hysteresis in studies on the hydraulic conductivity of peat soils

100%

Brzostowski E. , Olszta W.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

EN

The value of hydraulic conductivity (K) has considerable theoretical and practical significance for the water economy of soils and plants. Measurements of hydraulic conductivity conducted for peat soils in the process of soil monolith drying and wetting indicated the occurrence of capillary hysteresis in the soils under study. Data presented in the paper may indicate that the phenomenon is directly affected by the physical-hydraulic properties of the soils. The hysteresis loop surface areas determined in the study may be insufficient to fully reflect the true situation as there is a lack of measurements of the soil water potential in the zone close to full saturation. Values of the surface area calculated according to statistical methods differ from values calculated according to Brooks and Corey’s formulae. A significant factor affecting the difference is the value of effective conductivity (Kₑ) which is one half of the conductivity at full saturation (Ks).

PL

Wielkość przewodnictwa hydraulicznego (K) ma istotne znaczenie teoretyczne i praktyczne dla gospodarki wodnej gleb i roślin. Dokonane pomiary przewodności hydraulicznej K(h) gleb torfowych dla procesu osuszania i nawilżania monolitu glebowego wskazują na występowanie zjawiska histerezy kapilarnej w badanych glebach. Podane w pracy przykłady mogą świadczyć, że bezpośredni wpływ na to zjawisko mają ich właściwości fizyko-wodne. Określone tu powierzchnie pętli histerezy mogą nie w pełni odzwierciedlać stan faktyczny, gdyż brak jest pomiarów potencjału wodnego gleby w strefie bliskiej pełnego nasycenia. Powierzchnie te obliczone metodami statystycznymi różnią się od wartości obliczonych wzorami Brooks’a i Corey’a. Istotnym czynnikiem wpływającym na tę różnicę jest wielkość efektywnej przewodności (Kₑ) która stanowi połowę przewodności w stanie pełnego nasycenia (Ks).

6

Effects of swelly pressure on changes in pore space morphology in Miocene clays from Warsaw: preliminary results and open questions

100%

Gawriuczenkow I.

Geological Quarterly

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2003

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tom Vol. 47, No 2

215-220

EN

Miocene clays of the Poznań series from Warsaw were analysed by scanning electron microscope. The influence of swelly pressure causes soil porosity to decrease slightly together with a reorientation of pores. They become more anisometric, while their original matrix microstructure acquires properties of matrix-turbulent microstructure.

7

Influence of Cyclic Freezing and Thawing on the Hydraulic Conductivity of Selected Aggregates Used in the Construction of Green Roofs

100%

Gwóżdź K. , Hewełke E. A. , Sas W. , Żakowicz S. , Baryła A.

Journal of Ecological Engineering

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2016

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tom Vol. 17, nr 4

50--56

EN

The construction of a green roof requires drainage which ought to be characterized by adequate hydraulic conductivity and be resistant to changing meteorological conditions during the winter period. A properly functioning drainage system guarantees the reliability of the entire green roof system. The article presents studies on the freeze-thaw durability and hydraulic conductivity of selected aggregates applied for constructing green roof drainage systems. The aggregates were subjected to a cyclic freezing and thawing process in 30 and 70 cycles. The obtained results indicate that the conductivity of aggregates studied using the constant head method decreases along with an increase in the number of freeze-thaw cycles they were subjected to. This means that the indicator of freeze-thaw durability can have an indicative nature in the assessment of the usefulness of selected aggregates for constructing drainage layers. The conducted studies indicate that the deciding parameter when selecting an aggregate ought to be its hydraulic conductivity, determined accounting for the changes taking place in the freeze-thaw cycles. The equations of changes in the conductivity of aggregates indicated by the authors make it possible to assess them for practical purposes.

8

Pedotransfer function for determining saturated hydraulic conductivity using artificial neural network (ANN)

100%

Kruk E. , Malec M. , Klatka S. , Brodzinska-Cygan A. , Kolodziej J.

Acta Scientiarum Polonorum. Formatio Circumiectus

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2017

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tom 16

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nr 4

9

Verification of the Van Genuchten method of determination of the hydraulic conductivity of selected moorshed peat soils

100%

Brzostowski E. , Kowalski D. , Olszta W.

Journal of Water and Land Development

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1999

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tom no. 3

91-99

EN

The knowledge of hydraulic conductivity in unsaturated zone K(h) has a great theoretical and practical importance for soil water balance. The existing measurement methods of that parameter are rather complicated, so increasing interest appears in alternative, calculation methods. The article presents the results of laboratory tests of hydraulic conductivity of selected samples of peat soils, by dried monoliths method, and their companson with calculated values obtained by Van Genuchten's formula with Mualem, Burdine and Brutsaert variation.

PL

Znajomość przewodności hydraulicznej K(h) w strefie aeracji ma istotne znaczenie teoretyczne i praktyczne dla gospodarki wodnej w glebie szczególnie przy dynamicznym ujmowaniu stosunków wodnych. Przewodność hydrauliczną można oznaczać zarówno w warunkach polowych jak i laboratoryjnych lub obliczać według formuł analitycznych podanych w literaturze. Należy podkreślić, że wyznaczanie parametru K(h) jest trudne, szczególnie w warunkach polowych gdzie występują częste zmiany wilgotności gleby. Dlatego na coraz większą uwagę zasługują metody obliczeniowe. Obecnie brak jest wyników pomiarowych K(h) na tyle by można było określić charakterystykę gleb organicznych pod kątem przewodności hydraulicznej w strefie aeracji. Praca przedstawia wyniki badań laboratoryjnych przewodności hydraulicznej w strefie aeracji dla wybranych gleb torfowo-murszowych MtIaa i MtIIbc określonych metodą osuszanych monolitów i porównanie ich z otrzymanymi wartościami obliczeniowymi według formuły van Genuchtena w odmianie Mualema, Burdine'a i Brutsaerta. Biorąc pod uwagę zaprezentowane w artykule wyniki i ich dyskusję autorzy sugerują, że w chwili obecnej nie można stwierdzić istnienia pojedynczej metody obliczeniowej współczynnika K(h) uniwersalnej dla rozpatrywanych typów gleb. Autorzy artykułu wskazują na konieczność opracowania wykazu rodzaju gleb organicznych i odpowiednich dla nich modeli obliczeniowych.

10

Possible applications of hardening slurries with fly ash from thermal treatment of municipal sewage sludge in environmental protection structures

100%

Falaciński P. , Szarek Ł.

Archives of Hydro-Engineering and Environmental Mechanics

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2016

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tom Vol. 63, nr 1

47--61

EN

In Poland, in recent years, there has been a rapid accumulation of sewage sludge – a by-product in the treatment of urban wastewater. This has come about as a result of infrastructure renewal, specifically, the construction of modern sewage treatment plants. The more stringent regula tions and strategic goals adopted for modern sewage management have necessitated the application of modern engineering methodology for the disposal of sewage sludge. One approach is incineration. As a consequence, the amount of fly ash resulting from the thermal treatment of municipal sewage sludge has grown significantly. Hence, intensive work is in progress for environmentally safe management of this type of waste. The aim of the experiment was to evaluate the possibility of using the fly ash that results from municipal sewage sludge thermal treatment (SSTT) as an additive to hardening slurries. This type of hardening slurry with various types of additives, e.g. coal combustion products, is used in the construction of cut-off walls in hydraulic structures. The article presents the technological and functional parameters of hardening slurries with an addition of fly ash obtained by SSTT. Moreover, the usefulness of these slurries is analysed on the basis of their basic properties, i.e. density, contractual viscosity, water separation, struc- tural strength, volumetric density, hydraulic conductivity, compressive and tensile strength. The mandated requirements for slurries employed in the construction of cut-off walls in flood embankments are listed as a usefulness criteria. The article presents the potential uses of fly ash from SSTT in hardening slurry technology. It also suggests directions for further research to fully identify other potential uses of this by-product in this field.

11

Variability of horizontal hydraulic conductivity of fen peats from Eastern Poland in relation to function of peatlands as a natural geological barriers

100%

Rydelek P. , Bąkowska A. , Zawrzykraj P.

Geological Quarterly

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2015

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tom Vol. 59, No. 2

426--432

EN

This paper presents the test results of horizontal hydraulic conductivity (k) of fen peats from eastern Poland. Three fen peatlands in the Lubartów Plateau (3 objects marked as LP1, LP2 and LP3) and two in the Siedlce Plateau (2 objects marked as SP1 and SP2) have been selected. Studied objects represent valley bogs type and are similar in peat thickness, but different in the occupied area. They are also vary in terms of botanic compositions and basic physical and chemical parameters of peats. The BAT permeameter was used to in-situ measurements of horizontal hydraulic conductivity. Horizontal hydraulic conductivity of studied peats varies from 1.3×10-8 m/s to 1.1×10-6 m/s. The lowest values of horizontal hydraulic conductivity were observed for silted (high-ash) carbonate peats and amorphous or pseudo-fibrous peats, while the highest values were observed for unsilted (low-ash) non-carbonate peats of fibrous structure. The analysis of variability of horizontal hydraulic conductivity showed that in each case the lowest values were observed for the bottom of the studied profile. The study allowed to indicate the specific areas within the peatlands differing in permeability and identify the role of individual objects as natural geological barriers.

12

Sewage sludge as barrier material for heavy metals in waste landfill

100%

Zhang H. , Yang B. , Zhang G. , Zhang X.

Archives of Environmental Protection

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2016

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tom Vol. 42, no. 2

52--58

EN

Heavy metal pollutants in the leachate of waste landfill are a potential threat to the environment. In this study, the feasibility of using municipal sewage sludge as barrier material for the containment of heavy metal pollutants from solid waste landfills was evaluated by compaction test and hydraulic conductivity test concerning compaction property, impermeability and heavy metal retardation. Results of the compaction test showed that the maximum dry density of 0.79 g·cm−3 was achieved at the optimum water content of about 60%. The hydraulic conductivities of compacted sewage sludge permeated with synthetic heavy metal solutions were in the range of 1.3×10−8 – 6.2×10−9 cm·s−1, less than 1.0 ×10−−7cm·s−1 recommended by regulations for barrier materials. Chemical analyses on the effluent from the hydraulic conductivity tests indicated that the two target heavy metals, Zn and Cd in the permeants were all retarded by compacted sewage sludge, which might be attributed to the precipitation and adsorption of heavy metal ions. The results of this study suggest that specially prepared material from sewage sludge could be used as a barrier for waste landfills for its low permeability and strong retardation to heavy metal pollutants.

13

Modelling of karst genesis at the catchment scale - influence of spatially variable hydraulic conductivity

100%

Bauer S. , Liedl R. , Sauter M.

Acta Geologica Polonica

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2002

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tom Vol. 52, nr 1

13-21

EN

The aim of this work is to study the genesis of karst aquifers at the catchment scale. Especially the influence of different boundary conditions and geological setting is investigated in several scenarios. A hybrid continuum-discrete flow model is used for the modelling of conduit development. Effects of heterogeneity in hydraulic conductivity and in fracture spacing are examined in four scenarios. For homogeneous conditions a shallow water-table cave develops. If an area of reduced hydraulic conductivity is introduced, the conduit system evolves around this area and a deep phreatic cave is formed. This is true only, if the contrast in hydraulic conductivity is large enough. If an area of higher fracture density is introduced, this area is more intensely karstified, and a local system of deep karstification develops.

14

Verification of the Van Genuchten method of determination of the hydraulic conductivity of peat soils

100%

Olszta W. , Kowalski D.

International Agrophysics

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1996

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tom 10

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nr 2

15

An application of fluorescent tracer to groundwater tracking

88%

Cidzikienė V. , Jakimavičiūtė-Maselienė V. , Girgždienė R. , Ivanec-Goranina R.

Open Chemistry

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2015

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tom 13

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nr 1

EN

A well network at a potential new nuclear site in Lithuania examined a semi-confined intertill aquifer 10–19 m deep and an unconfined aquifer 4.5–9 m deep. Tracer results indicate a northwest flow direction and great hydraulic connection between observation and injection wells. Natural conditions affect tracer flow velocities.

16

Method to estimate water permeability functions of moderately wet soils with help of heat pipe technique

88%

Globus A. M. , Gee G. W. , Fayer M. , White M.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

EN

Water permeability of moderately wet soils, i.e., their unsaturated hydraulic conductivity and water diffusivity are seldom measured directly, yet are often needed by numerical models to simulate transport processes. These functions can be evaluated from steady state water content and temperature profiles in heat pipes - closed columns of uniformly moistened soil subjected to temperature gradient. For such systems Sw = DT/D(θ) = -dθ/dT where Sw is the thermogradient coefficient, DT is the thermal water diffusivity, D(θ) is isothermal water diffusivity and dθ/dT is the rate of change of water content with temperature deduced from steady state profiles of θ(x) and T(x), x - is the distance from one of column ends. DT varies in a relatively narrow range and can be assumed as a constant.Then D(θ) can be estimated as DTSw where Sw is measured in various locations along soil columns. Using water retention data, the steady water content profile can be procedure for estimating D(θ) can then be applied to estimate hydraulic conductivity, K(θ). Soil columns ranging in length from 5 to 10 cm, exposed to thermal gradients of l°C/cm for periods as short as 7 d, at initial suction values ranging from 1 to 1.5 MPa, can be used to estimate D and K with uncertainties of factor of five or less in the suction range from 0.03 to 3 Mpa.

PL

Zaproponowano metodę określania przepuszczalności hydraulicznej i dyfuzyjności wodnej gleby na podstawie profili ustalonej zawartości wody i temperatury w cieplnych rurach - zamkniętych kolumnach z równomiernie zwilżoną glebą poddaną gradientowi temperatury.

17

A new technique for hydraulic conductivity testing of expansive unsaturated soils

88%

Zakowicz S. , Garbulewski K.

Zeszyty Problemowe Postępów Nauk Rolniczych

|

1996

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tom 436

EN

A number of factors are known to influence the hydraulic conductivity (K) of soils. While a large number of laboratory and field methods have been developed over the years, most of them are applicable mainly for the measurement of hydraulic properties in saturated soils. Moreover, those methods omit such factors affecting hydraulic conductivity as soil volume changes (swelling or shrinkage) and external load simulating the location of the soil tested. The purpose of this paper is to present direct and simple methods for estimation of hydraulic properties, mainly conductivity of unsaturated soils. The methods proposed are based on evaluation of soil-water potential and water outflow from a soil sample. The test methods allow the 1- and 3-dimensional stress states of the soil and pore-fluid to be monitored. The procedure allows also to monitor the changing soil moisture using the TDR technique. The modified apparatus (triaxial apparatus, consolidometer and tempe pressure cell), soils and procedures are described first, and then the results of tests are presented and reviewed. Interpretation of test results is made using the Multi-step method. Results obtained showed that the stress states simulating the location of soil affected the hydraulic parameters significantly. The test results confirmed the usefulness of the methods proposed for testing the porous medium with the geometrical changes of soil (swelling/shrinkage) considered.

PL

Duża ilość czynników ma wpływ na przewodność hydrauliczną gleb nienasyconych. Do głównych możemy zaliczyć: wielkość i rozkład porów, wilgotność, gradient hydrauliczny, właściwości fizyczno-chemiczne cieczy biorącej udział w przepływie oraz stopień nasycenia gleby. Pomimo, że dotychczas stosuje się różne laboratoryjne metody przewodności hydraulicznej to większość z nich przystosowana jest do badań przewodności hydraulicznej gleb nasyconych. Ponadto stosowane metodyki nie uwzględniają takich czynników jak zmiany geometrii gleby (pęcznienie/skurczalność) i zewnętrzne obciążenie symulujące położenie gleby w profilu. W artykule przedstawiono metody określania przewodności hydraulicznej w pęczniejących nienasyconych glebach. Metody te oparte są na określeniu potencjału wody glebowej, objętości wypływającej wody z próbki i kontroli zmian uwilgotnienia metoda reflektometryczna (TDR). Interpretacja wyników badań oparta jest na metodzie Multi-step zaproponowanej przez Echinga i Hopmansa.

18

Quaternary aquifer transmissivity derived from vertical electrical sounding measurements in the semi-arid Khanasser Valley Region, Syria

88%

Asfahani J.

Acta Geophysica

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2012

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tom Vol. 60, no. 4

1143-1158

EN

Vertical electrical sounding technique (VES) is used as an alternative approach to pumping test for computing the Quaternary aquifer transmissivity in the Khanasser Valley, Northern Syria. The method is inexpensive, easy and gives faster results with higher special resolution than the traditional pumping technique. The hydraulic conductivity values obtained using VES agree with the pumping test results, which in the Khanasser Valley vary between the order of 0.864 and 8.64 m/day (10–5 and 10–4 m/s). The probable location of the Quaternary aquifer in the Khanasser Valley is obtained through the transmissivity map derived from VES. The knowledge of transmissivity is fundamental for modeling and management processes in the Khanasser Valley. Other similar semiarid regions can benefit from the approach successfully applied in the study area.

19

Wpływ wybranych czynników na przewodność hydrauliczną popiołu lotnego

88%

Wasil M.

Budownictwo i Inżynieria Środowiska

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2012

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tom Vol. 3, no. 1

67-73

PL

Przewodność hydrauliczna jest jednym z parametrów określających przydatność popiołów lotnych do budowli ziemnych. W pracy przedstawiono wpływ nasycenia wodą, zawartości procentowej cementu w próbce popiołowej oraz gradientu hydraulicznego na wartość przewodności hydraulicznej. Próbki zagęszczane były przy wilgotności optymalnej metodą standardową Proctora. Badania przeprowadzono w komorze konsolidacji hydraulicznej typu Rowe’a. Na podstawie wyników badań stwierdzono, że im mniejsze nasycenie próbki popiołowej wodą, tym mniejsze wartości prędkości przepływu. Zaobserwowano zmniejszenie wartości prędkości przepływu przy większej procentowej zawartości cementu w próbce.

EN

Hydraulic conductivity is one of the parameters which are used to determine usefulness of fly ash to earth structures. The paper presents the influence of some factors on value of permeability, such as: water-saturation, the addition of cement in the sample, hydraulic gradient and effective stress. The samples were compacted at optimum moisture content by means of Proctor’s method. Research was carried out in Rowe’s consolidation cell. It was found that the smaller water-saturation of fly ash sample, the lower the flow velocity. Higher percentage of cement in the sample affects the decrease of the flow velocity.

20

Colloids in Septic Tank Effluent and Their Influence on Filter Permeability

88%

Spychała M. , Nieć J. , Walczak N. , Marciniak A.

Journal of Ecological Engineering

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2015

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tom Vol. 16, nr 4

74--80

EN

The aim of the study was to evaluate the content of colloids in septic tank effluent and their impact on textile filter permeability. Measurements were performed on septic tank effluent without suspended solids but containing colloids and without colloids – including only dissolved substances (filtered by micro-filters and centrifuged). The study was conducted on unclogged and clogged textile filter coupons. During the study the following measurements were conducted: turbidity, chemical oxygen demand and hydraulic conductivity of textile filter coupons. The colloid size range was assumed to be less than 1.2 microns according to the literature. Despite the relatively low content in the septic tank effluent the colloids played an important role in the clogging process. Both the filtering media, filled with low (unclogged) and high content of biomass (clogged) were sensitive to the clogging process acceleration due to the possibility of small diameter pore closure and oxygen access termination. Moreover, small size pores were probably sensitive to closing or bridging by small size colloidal particles.