Tamer Elbana

Treated wastewater is a reliable water resource for agriculture in arid and semiarid areas. Nanomaterials are promising to clean wastewater. Here we review nanomaterials characteristics, reactivity and potentiality to reduce or remove pollutants from wastewater. Characteristics include high reactivity of surface areas, quantum confinement effects, surface charge density and stability of nanophases. We discuss applications to remove from inorganic and organic contaminants, with focus on reaction kinetics, sorption and degradation. Remediation efficiency is also controlled by wastewater properties such as pH, ionic strength and water temperature.

Sugarcane (Saccharum spp.) residue management, such as burning or sweeping (repositioning residue into the furrow), poses several challenges for producers and affects soil and water conservation practices. In this study, we evaluate the effect of postharvest residue management (mulch, burn, and sweep) on the yield of sugarcane at three different locations in south Louisiana during 2012 through 2016. Runoff and total solids loading, as well as total losses of ammonia (NH3), nitrate (NO3−), and dissolved phosphorus (P), were quantified during 2013 and 2014 growing seasons. Additionally, regression analyses between the runoff from mulch, burn, and sweep fields and the associated sediment and nutrient loading were carried out. The average measured cane yield (66.7 Mg ha−1) and sugar (7.97 Mg ha−1) did not differ among the different residue treatments, with p-values of 0.78 and 0.99, respectively. The runoff coefficient (in a range of 0.1 to 0.4) is found to be in ascending order as mulch fields < burn fields < sweep fields, and it proportionally enlarged by the increase of rainfall intensity. There were no significant differences in total solids loading and NH3 losses among the three residue management treatments. However, NO3− and dissolved P losses from the burn (0.54 and 0.02 kg ha−1, respectively) and sweep (1.04 and 0.29 kg ha−1, respectively) treatments exhibited significant differences during 2014. Based on these findings, mulching or sweeping the residue from the top of cane row is an acceptable management alternative to burning crop residue.

Batch kinetic experiments were carried out to quantify and describe the sorption/desorption of Cu and Pb in ten soils that exhibited a wide range of properties. Sorption isotherms were quantified using the Langmuir equation, whereas modeling of sorption/desorption kinetics was described using multireaction model (MRM). Results revealed the nonlinear sorption behavior of Cu and Pb in all soils. The ten soils exhibited higher affinity to Pb (6.4 to 36.5 mmol kg−1) in comparison to Cu (3.6 to 22.4 mmol kg−1). Simulation of Cu and Pb kinetic data indicated that the rate of sorption reaction was two orders of magnitude higher than the rate of release. Considering one irreversible site in addition to one-reversible kinetic site improved the estimation of rates of reaction for both Cu and Pb in acidic and alkaline soils. All soils exhibited sorption/desorption hysteresis where Pb-releases ranged between <0.2% and 14.4% of the total sorbed. The respective Cu releases ranged from <0.85...

Limited water resources in Egypt is the main factor driving the exploration of unconventional sources that can fulfill the water demands of the increasing population. Applying treated wastewater (TWW) to agriculture is a reliable, effective method of reducing the gap between current water demand and supply. Besides saving freshwater resources, long-term reuse of TWW can enhance the physiochemical properties of light-textured soil. Pathogens and toxic chemical bioaccumulation are the main drawbacks of wastewater reuse in agriculture. Irrigation of non-edible crops with TWW is recommended under controlled management that complies with appropriate water quality standards. Monitoring the impact of reusing TWW will reduce health risks and environmental hazards. While Egypt’s total water supply for 2015 was 76.4 × 109 m3, the total refined (drinking/health use) water was 8.9 × 109 m3, which generated wastewater of around 5 × 109 m3. The primary, secondary, and tertiary treatments provided total TWW of 3.7 × 109 m3, with respective percentages of 16.8, 81.4, and 1.8%. Several organizations in Egypt are tasked with wastewater management and reuse. In addition to the Egyptian laws, legislation, and regulations enacted to protect the environment and water resources from pollution, the Egyptian Code for reusing TWW classifies wastewater into four grades (A, B, C, and D) depending on the level of treatment. There are four key challenges to reusing TWW: social (public acceptance of wastewater reuse), management (crop selection, irrigation, and soil-based practices), human health risk, and environmental threats. There are significant opportunities to maximize the benefits of TWW reuse in Egypt as less than 75% of collected wastewater is currently being treated. Finally, reusing TWW in agriculture could be the most reliable solution to overcome water scarcity and help to sustain water resources in Egypt.

ABSTRACT Knowledge of the transport patterns of chemicals applied to soils is essential for environmental assessment of potential leaching to groundwater supplies. In this study, the mobility of imidacloprid applied to soils with different properties was investigated. The approach used was that of a modified miscible displacement, where soil columns under soil water-saturated conditions and constant flow velocity were maintained. The extent of imidacloprid mobility was measured by quantifying the concentration in the effluent solution versus time. All measured breakthrough curves (BTC) exhibited extensive asymmetry with sharp adsorption fronts. Imidacloprid exhibited high mobility in a silty kaolinitic (Mahan) soil, where 69% of the applied chemical was recovered in the effluent solution. In contrast, somewhat limited mobility was observed for Mhoon soil, with a high organic matter content (3.5%), where only 27% of applied imidacloprid was recovered. All BTC exhibited extensive tailing during leaching of the applied imidacloprid, indicative of the time-dependent release reactions of the adsorbed imidacloprid. A decrease in effluent concentration in response to flow interruption was also observed, which indicated kinetic retention of imidacloprid in all soils examined. The use of a linear model (CXTFIT) to simulate measured BTC showed good overall predictions. Concentration maxima and peak arrival time were well predicted by CXTFIT, but the slow release of imidacloprid during leaching was underestimated. The use of a multireaction and transport model proved successful in describing imidacloprid BTC for all soils. Based on measured BTC results, imidacloprid may be considered as a moderately mobile chemical that is susceptible to leaching from the soil profile.

ABSTRACT Understanding the transport and retention of heavy metals is essential in assessing their potential contamination of the ecosystem. In this study, four miscible displacement column experiments were performed to quantify lead (Pb) and tin (Sn) mobility in two loam soils. A pulse of Sn was applied to one set of columns; a second set received a pulse of a mixed solution of Sn and Pb, and a third set received a pulse of Sn followed by a pulse of Pb and vice versa. For all soils columns, Sn was not detected in the effluent which indicates that Sn is immobile and of high affinity. Analysis of the amount of Sn retained revealed that applied Sn was retained in the top 2 cm of the soil columns. For column of a reference sand material, Sn was more mobile with 32.4% recovery in the effluent. Unlike Sn, breakthrough curve results (BTCs) for Pb exhibited extensive mobility with Pb recoveries ranging from 52 to 96.4%. Lead was least mobile in columns where a pulse of Sn was applied before the application of Pb indicative of slowly reversible and irreversible reactions. A snow-plow effect was also observed where Pb concentration in the effluent exceeded that of the input pulse. Such observation suggests that retention processes of Pb should account for competitive sorption. The use of a second-order two site model (SOTS) which accounts for kinetic reversible and irreversible reactions was capable of providing good description of effluent results for Pb for all soil columns.

ABSTRACT Transport of heavy metals such as Cd is affected by several rate-limiting processes including adsorption and release reactions in soils. In this study, column transport and batch kinetic experiments were performed to assess Cd mobility in an acidic (Windsor) and an alkaline (Bustan) soil. Adsorption and desorption isotherms exhibited strong nonlinearity in both soils. A nonlinear multireaction and transport model (MRTM) successfully described adsorption with time as well as adsorption–desorption hysteresis. Breakthrough curves (BTCs) from column experiments indicated strong Cd retardation accompanied by slow release during leaching. The Cd was nearly immobile in the calcareous Bustan surface soil, whereas 20 and 30% of the applied Cd was mobile in the Windsor and Bustan subsurface soil columns. Sequential extractions of soils from the batch and column transport experiments indicated that Cd was associated with carbonates for the alkaline soil and with exchangeable and oxide fractions for the acidic Windsor soil. The MRTM was capable of describing the Cd arrival time in effluent and its concentration during leaching from the soil columns. When the CXTFIT model, which accounts for linear adsorption, was used, adequate overall predictions of the BTCs were obtained including the magnitude and time of peak arrival; however, effluent concentrations at advanced stages of leaching were underestimated. Sorbed Cd based on soil extractions vs. depth at the termination of column experiments were adequately described by the MRTM and CXTFIT.

... a School of Plant, Environmental and Soil Sciences, Louisiana State Univ. Agricultural Center, Baton Rouge, LA 70803. ↵*Corresponding author (mselim{at}agctr.lsu.edu). Next Section. Abstract. Miscible ... 1984). Rodriguez-Rubio et al. ...

ABSTRACT The fate of heavy metals, such as Pb, in the soil-water environment is significant in the assessment of their potential mobility and toxicity in the ecosystem. In this study, adsorption batch and sequential extraction experiments were carried out to assess the retention and reactivity of Sn and Pb in soils. Isotherm results exhibited highly nonlinear sorption for both heavy metals. Lead isotherms indicated a Freundlich exponent parameter b of 0.204 and 0.249 for Windsor and Olivier soils, respectively. The respective values for Sn were greater than 1 (2.46 and 3.72), which implies irreversible sorption. Moreover, Sn was completely sorbed, indicative of strong irreversible retention where more than 99% of the added Sn was retained in both soils. No Sn release after 30 days of desorption was detected. The presence of Sn resulted in reducing sorption of Pb by both soils, as evidenced by the decrease in their maximum sorption capacity; whereas, Pb exhibited kinetic behavior where 3 to 15% and 13 to 28% of Pb were released for Windsor and Olivier soils, respectively, during desorption. The use of a second-order two-site model that accounts for nonlinear equilibrium and kinetic reactions was capable of describing the kinetic behavior of Pb during adsorption and desorption in both Windsor and Olivier soils. Sequential extraction results revealed that the most susceptible Pb fraction for release was highest corresponding to highest Pb input concentrations. This concentration dependent release is consistent with the observed strong nonlinearity of Pb retention and implies that mobility of Pb tends to increase as the input Pb concentration is elevated. http://journals.lww.com/soilsci/Abstract/2013/08000/Adsorption_Desorption_of_Lead_and_Tin_in_Soils_.5.aspx

Agriculture is a key element of Egyptian socio-economic. With increasing pressure on the limited natural resources in Nile Valley and Delta, reclamation of new lands is highly required. Land reclamation seeks to transfer desert land to a productive agricultural land and support the infrastructure of new communities. The improvement of Newlands agricultural productivity is slow and faces several limitations and challenges due to their fragility. For the current research, the target area is proposed for reclamation and is located in the western desert of Egypt between 658014 to 660487 Easting and 3115299 to 3117050 Northing (UTM) with total coverage of 2.16 km2.The main objectives of this research were; a) to identify the general limitations for agriculture production in the study area, and b) to examine different management scenarios to reduce the impact of the limiting factors and enhance the agriculture productivity. Sixty two soil profiles were examined beside the collected irriga...

Miscible displacement column experiments were carried out in this study to assess mobility and reactivity of tin (Sn) and lead (Pb) in soils. Two soils were used, an Olivier soil (fine-silty, mixed, active, thermic Aquic Fraglossudalfs) and a Windsor soil (mixed, mesic Typic Udipsamments). Pulses of Sn and Pb were introduced consecutively (Pb - Sn and Sn-Pb pulse sequence) or mixed (Pb and Sn) into miscible displacement columns of water-saturated soils. Effluent results indicated extremely limited mobility of Sn where > 99% of applied Sn was retained in the columns for both soils. In contrast, breakthrough results for Pb exhibited extensive mobility in the two soils. Pb recovery in the effluent solution from Olivier soil columns was 57.6% and 96.4%, for the Sn-Pb pulse Pb-Sn pulse sequences, respectively. For Windsor soil, the respective Pb recoveries were 37.4% and 52%. A nonlinear equilibrium-kinetic multireaction approach was used to describe breakthrough curves (BTCs) for Pb ...

To investigate Ca release and reactivity as a subsequent influence of Cd sorption in soil, surface and subsurface soil samples (Typic Torripsamment) were collected from an area near Bustan in the northwestern desert of Egypt. Miscible displacement column and batch sorption experiments were performed. The strongest Cd sorption was observed in the surface soil layer having 2.8% CaCO3 in comparison with the subsurface layer having 1.2% CaCO3. The measurements of released Ca during Cd retention revealed the competitive interaction between the two elements on the sorption sites. After 24 h batch equilibration time, untreated soil samples, where no Cd added, showed that 5.097 and 4.891 mmol kg-1 of Ca were released from the surface, and the subsurface soils respectively. While, the presence of 0.178 mM of Cd for 24 h sorption time caused a release of 5.339+0.342, and 5.557+0.248 mmol kg-1 of Ca from surface and subsurface Bustan soils, respectively. Based on the column experiments, the Ca...

Transport of heavy metal such as zinc (Zn) in soils may be affected by several processes including kinetic sorption and release. In this study, the transport of Zn in soil columns for two acidic soils and one neutral soil was investigated. Another goal was to test the hypothesis that phosphate additions to soils increases zinc adsorption and consequently limits Zn mobility in soils. Column transport experiments were carried out using the miscible displacement technique where Zn pulses with or without P were introduced. Breakthrough results indicated that Zn mobility was strongly retarded with slow release during leaching. For Breakthrough curves (BTCs) with a mixed P and Zn pulse, lower Zn concentration were observed in the presence of P indicative of increased Zn sorption without affecting Zn arrival in the effluent solution. A multireaction model (MRTM) was capable of describing breakthrough results of Zn and P effluent concentrations and their slow release during leaching. Based ...

Infiltration column experiments were performed to assess the reactivity and mobility of As, Cd, Cu, Ni, and Zn under unsaturated flow conditions in soil. A mixed solution of As, Ni, and Zn was introduced into a 30-cm air-dry Commerce silt loam packed column. The heavy metal pulse was followed by a pulse of phosphate solution. Breakthrough results indicated early arrival of As in the effluent solutions when compared to Ni and Zn. The recoveries of applied As, Ni, and Zn were of 91%, 105%, and 71%, respectively. These results strongly indicate that, application of P pulse resulted in increased As mobility. In contrast, application of P pulse resulted in reduced mobility of Ni and Zn. In a second soil column, tritium, as a tracer, was mixed with the heavy metal solution of Cd, Cu, and Ni. This mixed pulse also followed by a pulse of phosphate solution. Complete recoveries of applied Cd and Ni were obtained whereas 51% of Cu was recovered in the effluent. Earlier arrivals of Cd and Ni i...

The purpose of this study was to establish critical soil compaction thresholds for M1A1 Abrams battle tank traffic in an effort to minimize soil physical properties that adversely affect vegetation regeneration. http://www.lsuagcenter.com/en/communications/publications/Publications+Catalog/research/Soils+and+Fertilizers/Soil-Compaction-Thresholds-for-the-M1A1-Abrams-Tank-Field-Study-at-Camp-Minden-La.htm

Abstract Egypt faces various challenges for managing water resources nowadays as a part of arid and semi-arid zone. The agriculture sector is the largest consumer for water supplies and the utilization of treated wastewater ―called also recycled water or reclaimed water‖ would provide multi benefits to include an affordable solution for water shortage and an economic pollution control measure. This literature review was intended to review the current and the potential use of treated wastewater for irrigation as well as the guidelines and regulations of treated wastewater use in Egypt. The current studies indicated that with the sufficient wastewater treatment, wastewater can be the most promising unconventional source, directly or indirectly, for agricultural irrigation. http://bio-nrc.jimdo.com/conferences/

In this study, kinetic batch and miscible displacement column methods were used to assess the reactivity and mobility of cadmium (Cd) in different soils. Two soils were used a Windsor Loamy sand surface soil from New Hampshire and Bustan sand surface and subsurface soils from Northwestern Egypt. The respective pH for the three soils was 6.1, 9.2 and 9.4, respectively. Bustan surface and subsurface soils contained 2.76 and 1.18% CaCO3, respectively. For all soils, isotherm results indicated strong sorption. Observed nonlinearities of Cd isotherms were generally described using Freundlich rather than Langmuir model. Cd release or desorption was strongly time-dependent and was associated with significant Ca release from the high pH Bustan soils. After 28 d desorption, only small amounts of the Cd already adsorbed were released. Specifically, based on the amount adsorbed, the amounts of Cd released or desorbed were 36% for Windsor, 3% for Bustan surface soil, and 31% for Bustan subsurfa...

ABSTRACT Rainfall simulation experiments were carried out to quantify the effectiveness of surface compost/mulch placed on highway embankments on runoff and soil and nutrient losses. Six of eight plots received either 5 or 10 cm thick surface compost/mulch. The plots were located in two highway locations; one in an active highway construction area on US 61, and another in an established area with continual rill and sheet erosion on I-49, West Feliciana and Rapides Parishes, Louisiana, respectively. A Tlaloc 3000 rainfall simulator at an intensity of 70–80 mm h−1 was used for the runoff experiments. Two consecutive pulses of 30 min durations were applied to each plot in 2011 and 2012. The presence of the compost/mulch resulted in a reduction of runoff flow rates from a high of 1.3 mm min−1 to a low of 0.4 mm min−1. The cumulative runoff losses as a percentage of the applied rainfall was 90% for a tilled plot (control) which was reduced to 28% in an adjacent plot having 10 cm compost/mulch. Regardless of their thickness, light tillage and incorporation of the compost/mulch reduced its effectiveness and increased runoff and soil losses. The antecedent soil moisture content during 2011 and 2012 seasons were distinctly different. Nevertheless, the presence of the compost/mulch provided similar runoff flow rates and soil losses for both years. We conclude that the presence of compost/mulch on the soil surface decreased runoff flow rate, soil and phosphate (P) losses and is recommended for highway embankment erosion control.

ABSTRACT Knowledge of the transport patterns of chemicals applied to soils is essential for environmental assessment of potential leaching to groundwater supplies. In this study, the mobility of imidacloprid applied to soils with different properties was investigated. The approach used was that of a modified miscible displacement, where soil columns under soil water-saturated conditions and constant flow velocity were maintained. The extent of imidacloprid mobility was measured by quantifying the concentration in the effluent solution versus time. All measured breakthrough curves (BTC) exhibited extensive asymmetry with sharp adsorption fronts. Imidacloprid exhibited high mobility in a silty kaolinitic (Mahan) soil, where 69% of the applied chemical was recovered in the effluent solution. In contrast, somewhat limited mobility was observed for Mhoon soil, with a high organic matter content (3.5%), where only 27% of applied imidacloprid was recovered. All BTC exhibited extensive tailing during leaching of the applied imidacloprid, indicative of the time-dependent release reactions of the adsorbed imidacloprid. A decrease in effluent concentration in response to flow interruption was also observed, which indicated kinetic retention of imidacloprid in all soils examined. The use of a linear model (CXTFIT) to simulate measured BTC showed good overall predictions. Concentration maxima and peak arrival time were well predicted by CXTFIT, but the slow release of imidacloprid during leaching was underestimated. The use of a multireaction and transport model proved successful in describing imidacloprid BTC for all soils. Based on measured BTC results, imidacloprid may be considered as a moderately mobile chemical that is susceptible to leaching from the soil profile.

Understanding the transport and retention of heavy metals is essential in assessing their potential contamination of the ecosystem. In this study, four miscible displacement column experiments were performed to quantify lead (Pb) and tin (Sn) mobility in two loam soils. A pulse of Sn was applied to one set of columns; a second set received a pulse of a mixed solution of Sn and Pb, and a third set received a pulse of Sn followed by a pulse of Pb and vice versa. For all soils columns, Sn was not detected in the effluent which indicates that Sn is immobile and of high affinity. Analysis of the amount of Sn retained revealed that applied Sn was retained in the top 2 cm of the soil columns. For column of a reference sand material, Sn was more mobile with 32.4% recovery in the effluent. Unlike Sn, breakthrough curve results (BTCs) for Pb exhibited extensive mobility with Pb recoveries ranging from 52 to 96.4%. Lead was least mobile in columns where a pulse of Sn was applied before the application of Pb indicative of slowly reversible and irreversible reactions. A snow-plow effect was also observed where Pb concentration in the effluent exceeded that of the input pulse. Such observation suggests that retention processes of Pb should account for competitive sorption. The use of a second-order two site model (SOTS) which accounts for kinetic reversible and irreversible reactions was capable of providing good description of effluent results for Pb for all soil columns

ABSTRACT Knowledge of the transport patterns of chemicals applied to soils is essential for environmental assessment of potential leaching to groundwater supplies. In this study, the mobility of imidacloprid applied to soils with different properties was investigated. The approach used was that of a modified miscible displacement, where soil columns under soil water-saturated conditions and constant flow velocity were maintained. The extent of imidacloprid mobility was measured by quantifying the concentration in the effluent solution versus time. All measured breakthrough curves (BTC) exhibited extensive asymmetry with sharp adsorption fronts. Imidacloprid exhibited high mobility in a silty kaolinitic (Mahan) soil, where 69% of the applied chemical was recovered in the effluent solution. In contrast, somewhat limited mobility was observed for Mhoon soil, with a high organic matter content (3.5%), where only 27% of applied imidacloprid was recovered. All BTC exhibited extensive tailing during leaching of the applied imidacloprid, indicative of the time-dependent release reactions of the adsorbed imidacloprid. A decrease in effluent concentration in response to flow interruption was also observed, which indicated kinetic retention of imidacloprid in all soils examined. The use of a linear model (CXTFIT) to simulate measured BTC showed good overall predictions. Concentration maxima and peak arrival time were well predicted by CXTFIT, but the slow release of imidacloprid during leaching was underestimated. The use of a multireaction and transport model proved successful in describing imidacloprid BTC for all soils. Based on measured BTC results, imidacloprid may be considered as a moderately mobile chemical that is susceptible to leaching from the soil profile.