Groundwater quality mapping of an alluvial aquifer, Eshtehard, Iran

Eshtehard aquifer located in southwest of Tehran province, Iran, provides a large amount of water requirement for inhabitants of Eshtehard district. Monitoring and analyzing of groundwater quality are important for protecting groundwater as sustainable water resource. One of the most advanced techniques for groundwater quality interpolation and mapping is geostatistics methods. The purposes of this study are (1) to investigate major ions concentration and their relative abundance to provide an overview of present groundwater chemistry and (2) to map the groundwater quality in the study area using geostatistics techniques. In this investigation, ArcGIS 9.2 was used for predicting spatial distribution of some groundwater characteristics such as: Chloride, Sulfate, pH, and Conductivity. These methods are applied for data from 44 wells within the study area. The final maps show that the south parts of the Eshtehard aquifer have suitable groundwater quality for human consumption and in general, the groundwater quality degrades south to north and west to east of the Eshtehard plain along the groundwater flow path

Groundwater quality assessment for different purposes in Eshtehard district, Tehran, Iran

Eshtehard district is characterized with semiarid climate and due to insufficient surface water resources, groundwater is the main water supply in this region. In order to evaluate the major suitability of water for drinking, domestic use and irrigation, the chemical characteristics of groundwater in Eshtehard district have been investigated and evaluated. Water samples from tube wells, dug wells and qanats are collected and analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), Na+, K+, Ca2+, Mg2+, HCO3-, Cl-, and SO42-. To understand the water quality and utilitarian aspects of groundwater, chemical indices like percent sodium, Sodium Adsorption Ratio (SAR), Wilcox diagram and Salinity diagram were calculated based on the analytical results. It is observed that the quality of groundwater is not suitable for drinking and domestic purpose in most water samples. According to the EC and SAR calculation the most dominant classes (C2-S1, C3-S2, C4-S3 and C4-S4) were found. Salinity hazard in 37% of water samples is regarded as medium while in 15 and 48% of water samples is classified as high and very high respectively. Such waters are not suitable for irrigation under normal condition and further action for salinity control is required in remediating such problem. Sodium content in 42% of water samples collected is regarded as low and can be used for irrigation in almost all soils. Thus high salinity, SAR and Na% in most water samples have restricted the water quality for irrigation purposes

Hydrogeological framework and groundwater balance of a semi-arid aquifer, a case study from Iran.

Climate changing and associated factors combined with considerably increases in water demand have been accompanied by severe depletion of reservoir storage of the most groundwater supplies of Iran. Shahriar aquifer in west of Tehran is a representative aquifer of these kinds. In order to meet water demand of the area and protecting groundwater from quantity and quality deterioration, precision recognition of geology, hydrologic and hydrogeologic characteristics of the aquifer is first step. The basic objective of this study is to develop the hydrogeological framework of the groundwater system in Shariar, Iran and to estimate ground-water balance as a scientific database for future water resources delevopment programs. Based on this re-search lateral groundwater inflows, direct infiltration of rainfall, stream bed infiltration, irrigation return and surplus drinking and industrial water are the recharging factors of the aquifer. Subsurface outflows, domestic and industrial pumping wells and agricultural abstraction are the main parameters discharge the aquifer system. Water balance in the Shahriar aquifer system is in disequilibrium and a deficit of about 24.7 million cubic meters exists

Geological and geoelectrical survey of groundwater potential in the Astaneh-Kouchesfahan plain, Iran.

The Astaneh-Kouchesfahan Plain, an extensive and productive aquifer system in Iran, is located in the south Caspian Sea basin which is part of the Alborz tectonic range in the Alpine fold belt. A permeable aquifer system provides water for industrial, agricultural and domestic uses. Geological and geophysical studies indicate a number of important facts about the groundwater system. For this reason, detailed regional geological, tectonic and geophysical data were gathered to better understand the behavior of hydrogeological zones in the system. Geological studies show that the area is predominantly covered by recent alluvium, which consists of Pleistocene and Holocene stream deposits, coastal deposits, beach deposits and alluvial fan deposits. The bedrock mainly consists of impermeable clay of the Mesozoic era. Also, based on available geological cross sections, geophysical surveys, and well logs, it is shown that the system contains an unconfined, shallow Quaternary alluvial aquifer which is composed of heterogeneous sequences of relatively coarse grained gravel and sand interconnected with different thicknesses of silt and clay. The final results of this study are extremely useful for geotechnical activities, environmental strategies, and water resource management

Enhanced coagulant extraction from Jatropha curcas in aqueous solutions and its application in turbidity removal

In this study, the effect of the extraction medium on the properties and efficiency of bio-coagulant, extracted of Jatropha curcas (Jc), in turbidity removal from aqueous solutions has been investigated. The optimized values of NaCl concentration (i.e., NaCl), solution pH and solution temperature were identified to improve the extraction of the coagulant. The optimized conditions were associated with an optimum coagulant dosage and a maximum turbidity removal from the synthetic aqueous solutions. The highest turbidity reduction was achieved with the coagulant extracted at a solution pH of 10 and an extraction temperature of 60°C (pH10/60°C-Jc press cake). Under these conditions, the coagulant dosage required was reduced by 80%–90%, depending on the coagulation pH. At the coagulation pH = 6, the pH10/60°C-Jc press cake well reduced the turbidity by 85%. However, the distilled water-based extract failed to lower the turbidity. Several analytical techniques were employed to characterize the nature of the active components derived from Jc. SDS-PAGE electrophoresis showed that Jc extract was mainly made up of proteins with molecular weights between 20 and 35 kDa. The optimized extraction conditions significantly improved the efficiency of this promising bio-derived coagulant in turbidity reduction. This study demonstrates the potential employability of these enhanced bio-coagulants. This can be a step ahead in helping with the development of sustainable processes in (waste)water treatment, particularly in tropical regions, for example, Malaysia with an abundant access to Jc

Evaluation of groundwater vulnerability to contamination and geochemical characteristics in an alluvial aquifer of Eshtehard plain, Iran

Amajority of the population in Eshtehard district depends upon the availability of quality groundwater from public or private sources. Eshtehard alluvial aquifer is the main source for irrigation, industrial and domestic uses. Recent anthropogenic activities, though, have created a potentially vulnerable environment as groundwater becomes exposed to contamination from municipal, industrial, and agricultural practices threatening the short and long term sustainability of high quality groundwater as a natural resource. Industrial discharge, waste disposal sites,application of pesticidesand fertilizers, poultry farms and municipal sewage are examples of potential source contamination in Eshtehard. Groundwater vulnerability to contamination from surface sources was evaluated for Eshtehard aquifer using a modified GIS based DRASTIC and GOD vulnerability methods. The study also evaluates groundwater quality and hydrochemistry. Chemical compositions of 114 groundwater samples were used to assess the groundwater quality in the study area and to validate the vulnerability mapsproduced by the two mentioned methods above. Most water samples aregrouped into two categories: relatively low mineralizedof Ca–HCO3 type and high mineralizedwaters of Na–Cl type,which indicate the intrusion of saline water and dissolution of carbonate minerals.Based onMANOVA test (P=0.05) on water samples collected during wet and dry seasons didn’t show any significant difference. Concentrations of most of the groundwater quality indicators exceed the maximum allowable limits set by WHO drinking water standards. The chemical analysis also indicates strong affect of anthropogenic activities on the groundwater quality as implied by high nitrate, chloride, and sulfateconcentrations. High levels of salinity and sodium content suggest that the most of groundwater samples are of poor to medium quality for irrigation purposes.The factor analysis reveals that there are two sources of solutes: (1) saline water intrusion with high loading of Cl, Na, Ca, EC, TDS and K; (2) anthropogenic activities, characterizedby high loadings of NO3, SO4 and Mg. For evaluating the groundwater vulnerability in Eshtehard area based on DRASTIC model, two challenging issues were encountered in this study: recharge estimation and alluvial media rating. Direct groundwater recharge from precipitation in semi arid areas is generally small, usually less than about 5% of the average annual precipitation, with a high temporal and spatial variability. A combined groundwater balance and water table fluctuation method was applied to estimate the groundwater recharge in the research area. Original rating tables provide sufficient detail for mapping at theregional scale, where broad ranges of geologic material are present. However,modified rating tables improved spatial representation of input parameters atlocal scales, which is useful for local planning. The DRASTIC and GOD’s index values and maps for Eshtehard alluvial aquifer were generated in GIS environment. The Classic DRASIC was modified and optimized by incorporation of simple statistical and geostatistical techniques for the revision of the factor rating and weighting of all the parameter. The criterionfor these modifications was based on the correlation coefficientof each parameter with the nitrates concentration in groundwater.The correlation coefficient was obtained as r = 0.53, r = 0.42 and r = 0.68 (p< 0.01) for the original DRASTIC, GOD and modified DRASTIC methods, respectively. On the basis of their statistical significance, original ratings and weighting of the parameters werechanged in the DRASTIC equation. Following the above-mentioned modifications,the correlation coefficient between groundwater pollution potential and nitrates concentration was considerably improvedand rose to 15% higher than the original method. The results also showed that both GOD and modified DRASTIC indices values are relatively high and thus Eshtehard aquifer is considered vulnerable to pollution. However, the results indicated that the vulnerability prediction by DRASTIC proved superior to GOD in this particular hydrogeologic setting. These classification of the vulnerability index showed that central and downstream parts of the aquifer are most vulnerable to pollution. The salt flat in north and the alluvial fans of the southern heights yielded moderate scores. The aquifer in and around Eshtehard township, industrial zone and cultivation lands are highly susceptible to contamination

Impact of carbon nanotubes based nanofluid on oil recovery efficiency using core flooding

This study aims to investigate the influence of carbon nanotubes based nanofluid on interfacial tension and oil recovery efficiency. Practically multi-walled carbon nanotubes were successfully synthesized using chemical vapour deposition technique and characterized using X-ray diffraction and Field Emission Scanning Electron microscope in order to understand its structure, shape, and morphology. Nanofluids are one of the interesting new agents for enhanced oil recovery (EOR) that can change the reservoir rock-fluid properties in terms of interfacial tension and wettability. In this work, different concentration of carbon nanotubes based fluids were prepared and the effect of each concentration on surface tension was determined using pendant drop method. After specifying the optimum concentration of carbon nanotubes based nanofluid, core flooding experiment was conducted by two pore volume of brine and two pore volume of nanofluid and then oil recovery factor was calculated. The results show that carbon nanotubes can bring in additional recovery factor of 18.57% in the glass bead sample. It has been observed that nanofluid with high surface tension value gives higher recovery. It was found that the optimum value of concentration is 0.3 wt% at which maximum surface tension of 33.46 mN/m and oil recovery factor of 18.57% was observed. This improvement in recovery factor can be recognized due to interfacial tension reduction and wettability alteration. Keywords: Carbon nanotubes (CNTs), Interfacial tension, Enhanced oil recovery (EOR), Nanoflui

Synthesis and Characterization of Yttrium Iron Garnet (YIG) Nanoparticles Activated by Electromagnetic Wave in Enhanced Oil Recovery

Due to the geographical location and technological limitation, various novel enhanced oil recovery (EOR) methods has been proposed to recover the remaining oil from a depleted oil reservoir. Research on application of nanoparticles either on its own or coupled with other stimulating agents has been growing enormously and some of them have shown a promising future. In high temperature and high pressure reservoirs, thermal degradation will cause failure to the conventional chemicals. In this work, temperature-stable YIG magnetic nanoparticles with an electromagnetic wave has been proposed as a new candidate for reservoir stimulating agent. The purpose of nanoparticle injection is to increase the sweep efficiency in the reservoir by increasing the viscosity of displacing fluid. In this research, Yttrium iron garnet (YIG) nanoparticles have been injected into a waterflooded oil saturated porous medium to recover the remaining oil in the presence of an electromagnetic wave. At the sintering temperature 1200°C, a mixture of hematite and YIG was obtained, suggesting a higher temperature for single phase YIG. From VSM analysis, the average magnetic saturation, coercivity and remanence are 18.17 emu/g, 21.73 Oe and 2.38 emu/g, respectively. 1.0 wt% of YIG nanofluid was prepared and subsequently injected into the pre-saturated porous medium in the presence of square electromagnetic wave of 13.6 MHz. As much as 43.64% of the remaining oil in place (ROIP) was recovered following the injection of 2 pore volume of YIG nanofluid

Synthesis and Characterization of Yttrium Iron Garnet (YIG) Nanoparticles Activated by Electromagnetic Wave in Enhanced Oil Recovery

Due to the geographical location and technological limitation, various novel enhanced oil recovery (EOR) methods has been proposed to recover the remaining oil from a depleted oil reservoir. Research on application of nanoparticles either on its own or coupled with other stimulating agents has been growing enormously and some of them have shown a promising future. In high temperature and high pressure reservoirs, thermal degradation will cause failure to the conventional chemicals. In this work, temperature-stable YIG magnetic nanoparticles with an electromagnetic wave has been proposed as a new candidate for reservoir stimulating agent. The purpose of nanoparticle injection is to increase the sweep efficiency in the reservoir by increasing the viscosity of displacing fluid. In this research, Yttrium iron garnet (YIG) nanoparticles have been injected into a waterflooded oil saturated porous medium to recover the remaining oil in the presence of an electromagnetic wave. At the sintering temperature 1200°C, a mixture of hematite and YIG was obtained, suggesting a higher temperature for single phase YIG. From VSM analysis, the average magnetic saturation, coercivity and remanence are 18.17 emu/g, 21.73 Oe and 2.38 emu/g, respectively. 1.0 wt% of YIG nanofluid was prepared and subsequently injected into the pre-saturated porous medium in the presence of square electromagnetic wave of 13.6 MHz. As much as 43.64% of the remaining oil in place (ROIP) was recovered following the injection of 2 pore volume of YIG nanofluid