scholarly journals Oil and grease in soils irrigated with greywater and the potential effect on soil water repellency

2007 ◽  
pp. 479-488
Author(s):  
Michael Travis ◽  
Noam Weisbrod ◽  
Amit Gross
Keyword(s):  
Soil Profile ◽  
Water Movement ◽  
Water Drop ◽  
Capillary Rise ◽  
Management Strategies ◽  
Water Repellency ◽  
Potential Effect ◽  
Oil And Grease ◽  
Ongoing Research ◽  
Order Of Magnitude

The reuse of greywater and other wastewaters are important considerations for effectivewater management strategies. It is also imperative that the potential for detrimentalenvironmental effects be investigated. As part of ongoing research into the reuse ofgreywater and oil-rich agro-wastewaters, the potential impact of oil and grease (O&G)to soils irrigated with greywater (GW) was studied. Greywater streams were sampledand analyzed for O&G content. Along with the greywater, soil profile samples werecollected from garden soils irrigated with these waters. The goal was to determine theO&G content of these GW streams, verify ifeO&G was accumulating in the soil profiles,and investigate the effect O&G can have on water movement through O&Gcontaminated soils.Untreated kitchen GW averaged 200 mg/L O&G, over an order of magnitude more thanother GW streams. GW-irrigated soils showed O&G accumulation of up to 200 mg/kgwithin the first 20-cm of depth. GW with low O&G concentration (<! 0 mg/L) stilldemonstrated long-tenn accumulation in the soil profile, with O&G concentration of150 mg/kg. To detennine the potential effects that O&G accumulation may have onwater movement in soil, capillary rise and water drop penetration time (WDPT)experiments were conducted. The results showed up to 60% decrease in capillary rise insand containing 250 mg/kg O&G. Interestingly, no additional reduction in capillary risewas observed at concentrations above 250 mg/kg. WDPT was observed to increaselinearly (from nearly instantaneous to over 2 seconds) with increased O&G content, upto 1000 mg/kg. This work demonstrated that O&G in GW used for irrigation canaccumulate in soil and may lead to a significant water repellency and reduction in thesoils ability to transmit water.

An evaluation of the intrinsic sorptivity water repellency index on a range of New Zealand soils

Soil Research ◽  
1991 ◽  
Vol 29 (3) ◽  
pp. 353 ◽  
Author(s):  
MG Wallis ◽  
DR Scotter ◽  
DJ Horne
Keyword(s):  
New Zealand ◽  
Water Drop ◽  
Water Repellency ◽  
Water Infiltration ◽  
Water Repellent ◽  
Ethanol Droplet ◽  
Wide Range ◽  
Order Of Magnitude ◽  
Moisture Conditions ◽  
Short Time

Undisturbed cores were removed from the surface of 14 New Zealand soils with a wide range of textures. The sorptivity to ethanol and water was measured with a 'sorptivity tube' to determine the repellency index (Rl) of each soil. Texture and gravimetric water content were measured, and the water drop penetration time (WDPT) and molarity of ethanol droplet (MED) tests for water repellency were conducted on the soils. The RI measured all soils water repellent (RI> 1.95) at field moisture conditions, and was more sensitive than the WDPT or MED tests. The RI was used to demonstrate that water repellency reduced short-time water infiltration of all soils by approximately an order of magnitude. Actual and 'potential' infiltration was then compared with rainfall and irrigation intensities. This illustrated the hydrological significance of the phenomenon, even in soils which appeared to wet normally (low WDPT). In all soils the curves of cumulative infiltration versus the square root of time for both water and ethanol stayed linear long enough for sorptivity evaluation. However, at longer times the slope of the curve tended to increase for water sorption in the more repellent soils, but decreased consistently for ethanol.

scholarly journals Ice Coverage Induced by Depositing a Water Drop onto the Supercooled Substrate at Extreme Low Vapor Pressure

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 691
Author(s):  
Yugang Zhao ◽  
Zichao Zuo ◽  
Haibo Tang ◽  
Xin Zhang
Keyword(s):  
Vapor Pressure ◽  
Substrate Temperature ◽  
Water Drop ◽  
Industrial Processes ◽  
Aircraft Icing ◽  
Ice Coverage ◽  
Fundamental Understanding ◽  
Order Of Magnitude ◽  
The Impact ◽  
Kinetics Of

Icing/snowing/frosting is ubiquitous in nature and industrial processes, and the accretion of ice mostly leads to catastrophic consequences. The existing understanding of icing is still limited, particularly for aircraft icing, where direct observation of the freezing dynamics is inaccessible. In this work, we investigate experimentally the impact and freezing of a water drop onto the supercooled substrate at extremely low vapor pressure, to mimic an aircraft passing through clouds at a relatively high altitude, engendering icing upon collisions with pendant drops. Special attention is focused on the ice coverage induced by an impinging drop, from the perimeter pointing outward along the radial direction. We observed two freezing regimes: (I) spread-recoil-freeze at the substrate temperature of Ts = −15.4 ± 0.2 °C and (II) spread (incomplete)-freeze at the substrate temperature of Ts = −22.1 ± 0.2 °C. The ice coverage is approximately one order of magnitude larger than the frozen drop itself, and counterintuitively, larger supercooling yields smaller ice coverage in the range of interest. We attribute the variation of ice coverage to the kinetics of vapor diffusion in the two regimes. This fundamental understanding benefits the design of new anti-icing technologies for aircraft.

Soil water repellency persistence after recurrent forest fires on Mount Carmel, Israel

2013 ◽  
Vol 22 (4) ◽  
pp. 515 ◽  
Author(s):  
Naama Tessler ◽  
Lea Wittenberg ◽  
Noam Greenbaum
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Forest Fires ◽  
Water Drop ◽  
Chemical Properties ◽  
Water Repellency ◽  
Mediterranean Ecosystem ◽  
Long Term Effects ◽  
Soil Water Repellency ◽  
Chemical Properties Of Soils

Variations in forest fires regime affect: (1) the natural patterns of community structure and vegetation; (2) the physico-chemical properties of soils and consequently (3) runoff, erosion and sediment yield. In recent decades the Mediterranean ecosystem of Mount Carmel, north-western Israel, is subjected to an increasing number of forest fires, thus, the objectives of the study were to evaluate the long-term effects of single and recurrent fires on soil water repellency (WR) and organic matter (OM) content. Water repellency was studied by applying water drop penetration time (WDPT) tests at sites burnt by single-fire, two fires, three fires and unburnt control sites. Water repellency in the burnt sites was significantly lower than in the unburnt control sites, and the soil maintained its wettability for more than 2 decades, whereas after recurrent fires, the rehabilitation was more complicated and protracted. The OM content was significantly lower after recurrent than after a single fire, causing a clear proportional decrease in WR. The rehabilitation of WR to natural values is highly dependent on restoration of organic matter and revegetation. Recurrent fires may cause a delay in recovery and reduced productivity of the soil for a long period.

Feasibility Study of Traffic Signals at Intersections in Peshawar, Pakistan

2012 ◽  
Vol 253-255 ◽  
pp. 1645-1649
Author(s):  
Rawid Khan ◽  
Ghulam Dastagir ◽  
Omar Shahid ◽  
Zeeshan Ahmed ◽  
Bashir Alam
Keyword(s):  
Traffic Management ◽  
Management Strategies ◽  
Traffic Signals ◽  
Level Of Service ◽  
Signal Timing ◽  
Traffic Data ◽  
Ongoing Research ◽  
The Road ◽  
Micro Simulation ◽  
Signal Time

The paper is part of an ongoing research project on traffic management strategies for Peshawar Pakistan. Traffic data collected and warrant tests checked at selected intersections. Peak hour vehicular volume warrant test selected and performed at intersections. Signal timing capacity and delay analysis performed and level of service determined for selected intersection. It was found that “for the same width of the road” the delay and level of service is different at different locations and the corresponding signal time is also different. Some data also analysed in 3D micro simulation.

scholarly journals Research and Management of Rare Diseases in the COVID-19 Pandemic Era: Challenges and Countermeasures

2021 ◽  
Vol 9 ◽  
Author(s):  
Sanjana Fatema Chowdhury ◽  
Syed Muktadir Al Sium ◽  
Saeed Anwar
Keyword(s):  
Rare Disease ◽  
Rare Diseases ◽  
Genetic Diseases ◽  
Management Strategies ◽  
Routine Care ◽  
Ongoing Research ◽  
The People ◽  
Number Of Patients ◽  
High Level ◽  
Disease Community

The ongoing coronavirus disease 2019 (COVID-19) pandemic has disrupted every aspect of our life. The need to provide high-level care for an enormous number of patients with COVID-19 infection during this pandemic has impacted resourcing for and restricted the routine care of all non-COVID-19 conditions. Since the beginning of the pandemic, the people living with rare disorders, who represent a marginalized group of the population even in a normal world, have not received enough attention that they deserve. Due to the pandemic situation, they have experienced (and experiencing) an extreme inadequacy of regular clinical services, counseling, and therapies they need, which have made their life more vulnerable and feel more marginalized. Besides, the clinicians, researchers, and scientists working on rare genetic diseases face extra challenges due to the pandemic. Many ongoing research projects and clinical trials for rare and genetic diseases were stalled to avoid patients' and research staff's transmission to COVID-19. Still, with all the odds, telehealth and virtual consultations for rare disease patients have shown hope. The clinical, organizational, and economic challenges faced by institutions, patients, their families, and the caregivers during the pandemic indicate the importance of ensuring continuity of care in managing rare diseases, including adequate diagnostics and priority management strategies for emergencies. In this review, we endeavored to shed light on the issues the rare disease community faces during the pandemic and the adaptations that could help the rare disease community to better sustain in the coming days.

Geochemistry and original nature of Precambrian khondalites in the Eastern Ghats, Orissa, India

1987 ◽  
Vol 78 (2) ◽  
pp. 115-127 ◽  
Author(s):  
B. Dash ◽  
K. N. Sahu ◽  
D. R. Bowes
Keyword(s):  
Soil Profile ◽  
Granulite Facies ◽  
Climatic Conditions ◽  
Eastern Ghats ◽  
Mass Wasting ◽  
Groundwater Movement ◽  
Weathered Soil ◽  
Average Analysis ◽  
Order Of Magnitude ◽  
Alkaline Earths

ABSTRACTThe quartz-sillimanite-garnet rocks of the Precambrian khondalite assemblage of Orissa consist dominantly of SiO2 + Al2O3 + Fe2O3 + FeO (average c. 95%) with Fe2O3 > FeO. An average analysis (H2O and CO2 free) also shows MgO, CaO and Na2O having 1·0, 0·5 and 0·4%, respectively. Compared with average crustal abundances, enrichment is shown in SiO2, Al2O3 and Fetot and depletion shown in MgO, CaO, Na2O and P2O5 with that for CaO being more than an order of magnitude and that for Na2O being a factor of >7. On an SiO2–Al2O3–Fetot plot a clearly defined field, elongate nearly parallel to the SiO2–Al2O3 sideline, is similar to that for deeply weathered soil profiles in Brazil. This correspondence also extends to enrichment, stability or depletion, compared to crustal averages, for Ce, Co, Cu, Ga, La, Ni, Nb, Th, U, Y, Zn and Zr, but not for Ba, Cr and Rb. In addition comparison of the proportions and ratios of alkalis and alkaline earths in average khondalite and in a weathering profile over a granodiorite, considered to be typical of the weathering of continents, shows remarkable similarities.The major and trace element data are consistent with the khondalites being granulite facies—upper amphibolite facies metamorphic equivalents of a deeply weathered soil profile. Associated quartzites and calc-silicate granulites are interpreted as having been silcretes and calcretes, respectively. This interpretation implies (1) the previous existence of a large stable cratonic mass on which the soil profile formed, (2) climatic conditions suitable for the development of such a profile, (3) topography, drainage systems and groundwater movement in Precambrian times similar to those of present day peneplane regions, (4) the presence of free oxygen in the atmosphere, (5) rapid covering (e.g. by products of volcanism) to preclude mass wasting, (6) a Precambrian stratigraphy in the crystalline rocks of the Eastern Ghats region similar to that of South India, and (7) orogenesis that involved tectonic repetition of lithological units and a mechanism for taking products of surface weathering down to granulite facies P–T conditions and subsequently elevating them.

scholarly journals Variability of water repellency in sandy forest soils under broadleaves and conifers in north-western Jutland/Denmark

2008 ◽  
Vol 3 (Special Issue No. 1) ◽  
pp. S155-S164 ◽  
Author(s):  
N.A Wahl
Keyword(s):  
Soil Water ◽  
Preferential Flow ◽  
Water Drop ◽  
Water Repellency ◽  
Climatic Conditions ◽  
Tree Age ◽  
Critical Surface ◽  
Soil Water Repellency ◽  
Wide Range ◽  
North Western

Soil water repellency has important consequences for ecological and hydrological properties of soils and usually retards infiltration capacity and induces preferential flow. This phenomenon has been known to occur on a wide range of sites under a variety of climatic conditions. The objective of this study was to investigate and characterize soil water repellency on forest sites with identical substrate and climatic conditions, differing in tree age and species. In the Vester Torup Klitplantage, an area comprising a conifer dominated forest plantation stocking on sandy deposits in a coastal setting near the Jammer Bay in north-western Jutland/Denmark, four different forest plots were investigated for water repellency effects four times in 2005. To measure soil water repellency, the water drop penetration time test and the critical surface tension test were carried out. Both tests revealed a seasonal variability in water repellency, exhibiting the highest water repellency for the upper 10 cm of the soil during the summer months, whereas the variability between the different plots seems to be less significant. There was no coherence between humus forms, thickness of litter layer and water repellency.

scholarly journals Field and numerical study of chlorotoluron transport in the soil profile

2011 ◽  
Vol 50 (No. 8) ◽  
pp. 333-338 ◽  
Author(s):  
R. Kodešová ◽  
J. Kozák ◽  
O. Vacek
Keyword(s):  
Adsorption Isotherm ◽  
Solute Transport ◽  
Soil Water ◽  
Soil Profile ◽  
Preferential Flow ◽  
Water Movement ◽  
Numerical Study ◽  
Soil Samples ◽  
Transport Parameters ◽  
Four Square

The transport of chlorotoluron in the soil profile under field conditions was studied. The herbicide Syncuran was applied on a four square meter plot using an application rate of 2.5 kg/ha active ingredient. Soil samples were taken after 119 days to study the residual chlorotoluron distribution in the soil profile. HYDRUS-1D (&Scaron;imůnek et al. 1998) was used to simulate water movement and herbicide transport in the soil profile. Soil hydraulic properties and their variability were studied previously by Kut&iacute;lek et al. (1989). The solute transport parameters, like the adsorption isotherm and the degradation rate, were determined in the laboratory. The Freundlich and Langmuir equations were used to fit the experimental data points of the adsorption isotherm, and the affect of each type of adsorption isotherm equation on the solute transport was studied. The chlorotoluron concentrations in soil water tended to be higher for the simulation performed with the Freundlich isotherm then that of the model using the Langmuir isotherm. In both cases, the solution did not pass a depth of8 cm. The simulated chlorotoluron concentrations in soil samples were higher then the observed concentrations when the chlorotoluron degradation was assumed to be in soil water only. Assumption of the solute degradation in both in the solid and the liquid phase significantly improved the accuracy of the solution. The different characters of the simulated and observed chlorotoluron distributions can probably be attributed to the preferential flow of water and solute in the soil profile and by variability of the transport parameters.

scholarly journals Role of unsaturated soil above a heavily contaminated aquifer in the natural attenuation of arsenic

2019 ◽  
Vol 98 ◽  
pp. 09017 ◽  
Author(s):  
Nadia Martínez-Villegas ◽  
Andrea del Pilar Gómez ◽  
Armando Zamora-Morales ◽  
Jejanny Lucero Hernández Martínez ◽  
Diana Meza-Figueroa ◽  
...  
Keyword(s):  
Natural Attenuation ◽  
Soil Profile ◽  
Particle Density ◽  
Capillary Rise ◽  
Arsenic Concentration ◽  
Shallow Aquifer ◽  
Horizontal Distance ◽  
Saturated Zone ◽  
Capillary Fringe ◽  
Arsenic Accumulation

Large attenuation of arsenic is observed in a shallow aquifer in central Mexico, where the concentration decreases from 91.5 to 11.3 mg/L, over 1.3 km horizontal distance. To investigate possible mechanisms of attenuation of this pollutant, we dug a pit between the surface and the saturated zone. We then described the soil profile and determined arsenic and iron concentrations in soil samples as a function of depth. Next, we determined particle size distribution, bulk density, particle density, soil moisture and porosity of the soil material. We also analyzed arsenic concentration in the groundwater. The 2.2 m deep profile intersected 4 soil horizons (A, AB, B1 and B2). We found arsenic accumulation in the B2 horizon, directly overlying the saturated zone. These accumulations coincide with the thickness of the capillary fringe, revealing that arsenic is drawn up in the soil profile by capillary rise of arsenic-contaminated groundwater. Furthermore, arsenic accumulation showed a direct relationship with iron, likely due to arsenic adsorption on iron oxides. Results from this study contribute to understanding a capillary-driven natural attenuation mechanism that removes contaminants from groundwater by sinking them in the capillary fringe.

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