High Total Dissolved Solids Research Articles

On The Evaluation of Water Quality Index: Case Study of Euphrates River, Iraq

This study is used the water quality index (WQI), which is generated by combining several water quality parameters. This index gives a helpful representation of overall water quality for the public and all intended applications, and it demonstrates that pollution is beneficial in water quality management and decision-making. The Euphrates River was assessed in order to determine the quality of drinking water. The Euphrates River was assessed for drinking water quality using the WQI, which includes ten physicochemical water quality criteria. This was achieved by submitting comprehensive physicochemical analysis of water samples collected from 5 stations in the city of Hit-Iraq during 2020-2021. The ten physicochemical parameters included: pH value, Nitrate (NO3), Sulphate (SO4­), Turbidity, temperature, Calcium (Ca), Magnesium (Mg), sodium (Na), electric conductivity (EC) and Total Dissolved Solids (TDS). This was accomplished by submitting a full physicochemical analysis of water samples obtained from 5 sites in Hit, Iraq, between 2020 and 2021. The results of the present study show, the total average WQI was 110,156. The high WQI achieved is caused by the high TDS and magnesium concentration due to the different human activities along the river reach. The Euphrates River quality is classified as 'very poor quality' with a minimum WQI of 97.85 in June and 121.75 in November.

Sonolytic destruction of Per- and polyfluoroalkyl substances in groundwater, aqueous Film-Forming Foams, and investigation derived waste

Per- and polyfluoroalkyl substances (PFASs) are anthropogenic amphipathic heat-resistant materials found in some household products and Aqueous Film-Forming Foams (AFFFs) used to extinguish hydrocarbon fires. There is a critical need for developing destructive technologies for the treatment of PFAS-impacted waters because several PFASs are classified as probable carcinogens and endocrine disruptors. We tested the destruction of 7 individual PFASs, a mix of 24 native PFASs (24Mix), and samples of AFFF and concentrated Investigation Derived Waste (IDW) by high-frequency ultrasound (700 kHz – 1040 W) in deionized water, groundwater containing low total dissolved solids (TDS) (388 mg L−1), and high-TDS groundwater (10.2 g L−1). This study demonstrated the degradation of novel PFASs, hexafluoropropylene oxide dimer acid (HFPO-DA) and 6:2 fluorotelomer sulfonamidoalkyl betaine (6:2 FTAB), with near-stoichiometric fluoride release. The salts and surfactants affect the air-water partitioning coefficients of PFASs and their availability at the ultrasonic cavity, thereby affecting the degradation rates. The degradation rates of sulfonates and short-chain PFASs were 30% to 60% higher in low TDS groundwater than those in deionized water, while the rates were lower in high TDS groundwater. The degradation rates of sulfonates in AFFF were 40% to 60% higher as compared to the 24Mix. The treatment of concentrated, high-TDS IDW resulted in significant defluorination of 41 PFASs, consuming 3 kWh g−1 – 76 kWh g−1 whereas dilute AFFF degradation utilized 5900 kWh g−1. The results inform important parameters for designing and operating ultrasonic reactors for the degradation of PFASs and verify that sonolytic treatment of concentrated PFAS mixtures and AFFF IDWs can effectively degrade and defluorinate PFASs without the formation of disinfection by-products.

Hydrogeochemistry of Fluorine in Groundwater in Humid Mountainous Areas: A Case Study at Xingguo County, Southern China

The understanding of F− concentration in groundwater in humid areas is limited although there are lots of research on high-fluoride groundwater in arid areas. In this paper, with controlling factors of F− concentrations in humid areas as the focus, 130 groundwater samples, obtained from four subsystems in Northwest Xingguo County, Jiangxi Province, China, were investigated to demonstrate the controlling factors of F− concentrations in humid areas. According to analytical results, the following hydrogeochemical characteristics of the fluorine in humid mountainous areas were determined: (1) F− concentration is positively correlated with total dissolved solids (TDS), Ca2+, HCO 3 − , and pH; (2) the groundwater features a high flow rate and low TDS; (3) the equilibrium constant of CaF2 is less than its solubility product constant, and the fluorine-bearing minerals in rocks are in a dissolved state; and (4) the dissolved fluoride-bearing minerals constitute the main sources of F− in the groundwater. Fluorine mainly comes from groundwater fluorine-bearing minerals in metamorphic rocks. Moreover, the low F− concentration in the groundwater mainly results from the fast flow rate of groundwater. Fluoride in groundwater has great potential hazards in humid areas.

Techno-commercial Assessment of Concurrent Municipal Brown Field Reclamation Procedures: A Pivotal Case study of Jawahar Nagar Dump Site

Techno-commercial Assessment of Concurrent Municipal Brown Field Reclamation Procedures: A Pivotal Case study of Jawahar Nagar Dump Site

Comments: Water Pressures

Drought conditions rated as “moderate or worse” affected 31 US states as of 8 June, as reported by the US National Integrated Drought Information System. Particularly dry are the West and Upper Midwest regions, relevant to the Permian and Bakken, respectively. While not a record-level drought, attention is turning to the Missouri River in North Dakota where streamflow levels are at low levels for this time of year—about 48% below the seasonal average. About 96% of the water in North Dakota’s rivers and streams flows through it, making it one of the main sources of fresh water for oil and gas production in the Bakken. In the extreme drought, water restrictions could come into play. Throughout the industry, recycling and reuse of frac and produced water have been studied, and where the chemical makeup of the frac or produced water is suitable for optimal and economical treatment, it has been implemented. However, Bakken production is typically associated with 1.0 to 1.5 bbl of produced water per barrel of oil (a water cut of approximately 50%). It is highly saline with total dissolved solids (TDS) ranging up to 350,000 mg/L (seawater is about 35,000, or 10 times less salty than Bakken brine). Treatment options for such high TDS levels are limited and often cost-prohibitive. The Bakken’s produced water volumes increased fourfold since 2008 to about 740 million bbl per year due to increasing volumes per well and increasing water cut. Produced water disposal volumes in the same period increased fivefold to about 680 million bbl per year. More than 95% of saltwater disposal (SWD) targets the Inyan Kara Formation, the lowermost sandstone interval of the Dakota Group. The increase in SWD volumes has resulted in localized areas of high pressure in the formation in geographic regions associated with high levels of oil and gas activity. This increased pressure affects the economics and risk associated with the drilling of new wells that now require additional intermediate casing strings (“Dakota Strings”), adding a cost of $300,000 to $700,000 per well. About 200 wells to date have been identified with additional casing strings, according to the Energy & Environmental Research Center (EERC). Faced with the challenges of high salinity in recycling/reuse of produced water, constraints on SWD injection, freshwater limitations, pressure regulation, and inflated drilling costs, a 2-year project was begun in January 2020 which may hold promise for greater use of the produced water. Participants in the $1.3-million project are EERC, Nuverra Environmental Solutions, and the US Department of Energy.

Groundwater quality evaluation using Water Quality Index and GIS technique for the Holocene and Pleistocene aquifers in the coastal zone of Ninh Thuan province

This study represents the application of the Water Quality Indices (WQI) and GIS techniques to grading water pollution and the factors that influenced the groundwater quality of the Holocene (qh) and Pleistocene (qp) aquifers in the coastal zone of Ninh Thuan province. 100 underground water samples were collected from residential water well of qh aquifer (53 samples) and qp aquifer (47 samples). Water quality indices using in the study incorporated total dissolved solids (TDS), chloride (Cl-), flouride (F-), nitrite (NO2-), nitrate (NO3-), iron (Fe3+), manganese (Mn2+). Calculated WQI grading scale for the groundwater quality of the 100 water samples ranged from very good to inedible for drinking purpose. The result shown the water sample graded as “excellent water quality” accounted the most (23,3% and 14,9% for the qh and qp aquifer, respectively), the followings were “good water quality” grade ranked the second (9,4% and 8,5%); “poor water quality” grade (43,4% and 30,04%); “very poor water quality” grade (1,89% and 10,64%); and “inedible” grade (16,98% and 31,9%). Water samples graded as “very poor” and “inedible” were mostly distributed on the southeast of Ninh Hai district and Tri Hai commune (Ninh Hai district), Xuan Hai and Cong Hai communes (Thuan Bac district), Phuoc Thuan (Ninh Phuoc district) of the qh aquifer, and to the south of study area of the qp aquifer because of the exceptionally high TDS. Other samples which were low on TDS but graded “bad” due to surprisingly high concentrations of other ions (Cl-, NO3-, NO2-). The result provided concreted information on the polluted agents in groundwater and a valuable tool to support authorities in management and zoning groundwater quality of the study area.

Bioremediation of ossein effluents using the filamentous marine cyanobacterium Cylindrospermum stagnale

Wastewater containg proteinaceous ossein effluents are problematic to be treated. We studied the possibility to treat ossein effluents with the marine cyanobacterium strain Cylindrospermum stagnale. After optimizing the culture conditions of the bacterium, three different types of ossein effluents were tested: dicalcium phosphate (DCP), high total dissolved solids (HTDS) and low total dissolved (LTDS). The effluents were diluted with sea water at the following ratios 1:1, 2:1 and 3:2. The optimum operating conditions were at 3000 lux light intensity and 37 °C temperature. The highest degradation of ossein effluens by C. stagnale was attained for a dilution ratio of 1:1. However, less diluted ossein effluents reduced the growth of C. stagnale drastically. The degradation was shown by measuring the chlorophyll a content and the dry weight of bacterial cells during a seven-day incubation period degradation. Fourier Transform Infrared Spectroscopy (FT-IR) analysis verified the degradation showing the presence of the degradation products of ossein (i.e. calcium carbonate and calcite) in the culture medium. Lipid composition in fatty acids appeared to be suitable for biofuel production. The results showed that the marine cyanobacterium C. stagnale can be used to treat ossein effluents, and at the same time, to produce biofuel in a sustainable way.

Evolution of a Deep Fluid in a Surficial Environment Using Stable Carbon and Sulfur Isotopes: Case of the Transitional Zone of the Edwards Aquifer in South Central Texas

The Edwards Aquifer in south central Texas (USA) features a distinct fault line defining the freshwater and saline water zones. We aim to elucidate the evolutionary behavior of carbon and sulfur emanating from deep environments and flowing in surficial environment so as to better understand the cycling of these metals in water environments. To characterize the evolution of carbon and sulfur species in surficial environment as the fluid emanates from a deep saline aquifer, we monitored the chemical and isotopic (δ13CDIC and δ34SSO4) parameters over a 700-m stretch on a stream-pond system situated on the saline-freshwater line of the Edwards Aquifer’s artesian zone. A three-tier evolution process associated with the interaction of a deep saline fluid with a fresh-ponded water was observed, namely: A deep fluid control zone characterized by decreasing pH values and relatively high total dissolved solids (TDS) concentrations along the stream path; a mixing zone of the deep fluid and fresh-ponded water where the TDS concentrations showed a sharp decline and a continual decrease in pH values; and a fresh-ponded water-controlled zone with a stable pH value and low TDS concentrations. The decreasing pH values were a result of CO2 outgassing due to the relatively high CO2 partial pressures (10–2.53 atm) relative to atmospheric (10–3.50 atm) in the aqueous system, and the high TDS concentrations were attributed to the deep saline fluid emanating at the well-head. The enrichment in the δ13CDIC and δ34SSO4 for the initial stream path reflects the kinetic isotopic fractionations associated with CO2 outgassing and with the microbial conversion. The zonation of the evolutionary process indicates that (i) solutes play a critical role in the evolution of carbon and sulfur in surficial environment, (ii) kinetic and chemical fractionation are the dominant processes controlling carbon evolution, and (iii) microbial metabolism primarily controls sulfate fractionation and evolution through the conversion of sulfate to thiosulfate.

Environmental sustainability and prevention of heavy metal pollution of some geo-materials within a city in southwestern Nigeria

Increased anthropogenic activities may cause the release of potentially hazardous metals into the environment. This is a major public health concern. The study was aimed at accessing ways by which pollution can be prevented with enhanced environmental sustainability in Ibadan, Southwestern, Nigeria. Geo-materials (groundwater, soil and stream sediment) were collected, analyzed for heavy metals using inductively coupled plasma-mass spectrometry. Results of acidity (pH), electrical conductivity (EC), total dissolved solid (TDS) and heavy metals (Zn, As, and Cd) obtained in water were compared with WHO permissible limits. All parameters were found within WHO permissible limits except TDS (624.35 mg/L). Risk index showed dangerous to extremely dangerous. High TDS can be attributed to weathering while high Cd, Zn and Pb in stream sediment and soil are due to anthropogenic effect. Provision of adequate disposal facilities should be created by private and government agencies and the use of it must be enforced.

Assessment of the HablehRood river water quality for drinking and irrigation purposes in Garmsar, Iran

Rivers are one of the most valuable sources of water for drinking, agricultural, and industrial use. In the presented study, water samples collected from different rivers of HablehRood from October Within 23, 2009, to the end of September 2014, were analyzed to assess qualitative analysis and suitability for domestic and irrigation usage. The electrical conductivity (EC) of the river water was within the range of 750–5000 μmoh/cm, sodium adsorption ratio (SAR) Classification indicated that all samples were excellent and good range, sodium percentage (Na %) 20–80%, residual sodium carbonate (RSC) $${\mathrm{Na}}^{+}{\mathrm{Mg}}^{2+}$$ > $${\mathrm{Ca}}^{2+}$$ and $${\mathrm{Cl}}^{-}$$ > $${\mathrm{SO}}_{4}^{2-}$$ > $${\mathrm{HCO}}^{-}_{3}$$ . The water quality showed high EC and total dissolved solids (TDS) in all water samples, which reduce quality for livestock and drinking because of high TDS levels. Still, according to the Wilcox diagram is suitable for agriculture.

Hydrogeochemical characteristic evaluation and irrigation suitability assessment of shallow groundwater in Dangshan County, China

The current study aims to identify the hydrogeochemical characteristics, formation mechanism and evolution law of shallow groundwater in Dangshan, China, and to evaluate the suitability of the groundwater for irrigation. In this study, ninety-six samples were taken to investigate the hydrogeochemical characteristics of shallow groundwater in Dangshan County. The geographic information system (GIS) method was used to analyse the spatial distribution characteristics of total dissolved solids (TDS). Gibbs diagram, Binary relation analysis and reverse geochemical reaction simulation method were utilised to reveal the main formation mechanism of relatively high TDS in this region. The results show that water-rock interaction and evapotranspiration are the main mechanisms for controlling the chemical evolution of shallow groundwater in wet and dry seasons in the study area, respectively. The main waterrock interactions in the study area include dissolution of halite and dolomite, the precipitation of gypsum, as well as cation exchange and adsorption. Suitability of shallow groundwater quality for irrigation use was evaluated according to the sodium adsorption ratio (SAR) and the electrical conductivity (EC) with a United States Salinity Laboratory (USSL) diagram. Meanwhile, GIS technology was used to demonstrate the spatial distribution of irrigation suitability variations. Based on the spatial interpolation result on the USSL salinity diagram classification, the shallow groundwater in 89% of the study area is suitable for irrigation, while 11% of the area is unsuitable for irrigation.

Numerical modeling and experimental investigation on the effect of low-salinity water flooding for enhanced oil recovery in carbonate reservoirs

Numerous studies concluded that water injection with modified ionic content/salinity in sandstones would enhance the oil recovery factor due to some mechanisms. However, the effects of smart water on carbonated formations are still indeterminate due to a lack of experimental investigations and researches. This study investigates the effects of low-salinity (Low Sal) solutions and its ionic content on interfacial tension (IFT) reduction in one of the southwestern Iranian carbonated reservoirs. A set of organized tests are designed and performed to find each ion’s effects and total dissolved solids (TDS) on the candidate carbonated reservoir. A sequence of wettability and IFT (at reservoir temperature) tests are performed to observe the effects of controlling ions (sulfate, magnesium, calcium, and sodium) and different salinities on the main mechanisms (i.e., wettability alteration and IFT reduction). All IFT tests are performed at reservoir temperature (198 °F) to minimize the difference between reservoir and laboratory-observed alterations. In this paper, the effects of four different ions (SO42-, Ca2+, Mg2+, Na+) and total salinity TDS (40,000, 20,000, 5000 ppm) are investigated. From all obtained results, the best two conditions are applied in core flooding tests to obtain the relative permeability alterations using unsteady-state methods and Cydarex software. The final part is the simulation of the whole process using the Schlumberger Eclipse black oil simulator (E100, Ver. 2010) on the candidate reservoir sector. To conclude, at Low Sal (i.e., 5000 ppm), the sulfate ion increases sulfate concentration lower IFT, while in higher salinities, increasing sulfate ion increases IFT. Also, increasing calcium concentration at high TDS (i.e., 40,000 ppm) decreases the amount of wettability alteration. In comparison, in lower TDS values (20,000 and 5000 ppm), calcium shows a positive effect, and its concentration enhanced the alteration process. Using Low Sal solutions at water cut equal or below 10% lowers recovery rate during simulations while lowering the ultimate recovery of less than 5%.

Impact of Waste and Industrial Effluent on Ground Water Quality Index in Rabigh Area, Makkah Region, Kingdom of Saudi Arabia

The quality of surface water and groundwater has deteriorated as a result of increased industrialization, urbanization and agricultural practices during the last few decades. Contaminated groundwater can cause major health problems in humans, such as typhoid and other infections. Similar in the case of Rabigh Governorate, the groundwater is one of the main sources of water for domestic and agriculture purposes in its villages situated in western Saudi Arabia. Many factories have been established in Rabigh region in recent years and day to day input of numerous untreated/partially treated water resulting in major environmental problems, one of which is the low quality of groundwater causing serious environmental and health issues. The presented study discusses the ground water as the main available and usable source in extremely climatic condition of arid area of Saudi Arabia. The article proceeds with the brief introduction of ground water, its contamination sources and health hazards. For this, 13 water samples were from the randomly selected wells in Rabigh Governorate for quality examine. Water quality index analysis was conducted, which is a useful technique for fast assessment of the quality of any water resource. Various physical and chemical parameters of water quality index such as pH, temperature, conductivity, turbidity, total dissolved solids (TDS), total suspended solids (TSS), total solids (TS), dissolved oxygen (DO), arsenic and E. coli are measured and analyzed. The values of all groundwater samples are compared with the standard WHO permissible values. The water quality of the wells were classified into “good, poor, very poor and unsuitable for drinking” based on physico-chemical parameters. According to the observed study, water quality range (WQR) for 5 samples (38% of the samples) are of poor quality, 3 samples (23%) are recorded with a very poor quality and 5 samples (38%) are not suitable for drinking purpose due to presence of high conductivity and TDS values. After taking into consideration the presence of E. coli in 31% of the samples (n = 4), about 62% of the samples (n = 8) are not suitable for drinking purpose, only 23% (n = 3) samples are of poor quality and 15% (n = 2) are very poor quality. The findings reveal a decrease in water quality (unsuitable for drinking purpose) in 8 out of 13 collected samples. It is believed that waste and industrial activities have an impact on groundwater quality in the study area, however, a nationwide investigation should be conducted to validate this finding.

Evaluation of sequencing batch bioreactor followed by media filtration for organic carbon and nitrogen removal in produced water

Produced water contains high concentrations of total dissolved solids (TDS), metals, and organic matter. In areas of high water stress, beneficial reuse of produced water needs to be considered. This study evaluates the treatment capabilities, efficiency, and limitations of a sequencing batch reactor (SBR) to remove organic material and nutrients from produced water. SBRs have been used to facilitate biological organic and nutrient removal from municipal and industrial waste streams. Although the bacteria responsible for the treatment of municipal and most industrial wastewaters cannot tolerate the high TDS concentrations in produced water, the microorganisms native to produced water have the capacity to treat produced water. In a bench scale bioreactor test using produced water from the Denver-Julesburg Basin, the produced water was determined to be nutrient limited with respect to phosphorus. By adding a phosphorus supplement, soluble chemical oxygen demand (COD) removal was increased by over 20 % and ammonia removal increased by approximately 40 %. Various supplements, including KH2PO4, centrate from an anaerobic digester, and activated sludge from a municipal SBR, were added to the bioreactors to determine which of them was more effective. A pilot scale SBR followed by media filtration was used to evaluate the effects of operating conditions on produced water treatment. The hydraulic residence time ranged from 1.67 to 8.3 days during various phases of operation, with no measured effect on treatment performance. Adding 7.5 mg-P/L of KH2PO4 as a phosphorus supplement had the most significant effect on treatment performance of the system. The majority of COD removal switched locations from the filter columns to the bioreactors. Comparing total organic carbon to COD, the biologically available portion of COD appears to be treated in the SBR while recalcitrant carbon and inorganic material may need to be removed via physical or chemical methods.

Hydrochemical Parameters to Assess the Evolutionary Process of CO2-Rich Spring Water: A Suggestion for Evaluating CO2 Leakage Stages in Silicate Rocks

Eighteen water samples collected from eight CO2-rich springs in the northern part of the Gyeongsang sedimentary basin (GSB), South Korea showed distinct hydrochemistry, in particular, pH, total dissolved solids (TDS), and Na contents, and they were classified into four groups: (1) Group I with low pH (average of 5.14) and TDS (269.8 mg/L), (2) Group II with high TDS (2681.0 mg/L) and Na-enriched (202.9 mg/L), (3) Group III with intermediate Na content (97.5 mg/L), and (4) Group IV with Na-depleted (42.3 mg/L). However, they showed the similar partial pressure of CO2 (0.47 to 2.19 atm) and stable carbon isotope ratios of dissolved inorganic carbon (−6.3 to −0.6‰), indicating the inflow of deep-seated CO2 into aquifers along faults. In order to elucidate the evolutionary process for each group of CO2-rich springs, a multidisciplinary approach was used combining stable hydrogen (δD), oxygen (δ18O) and carbon (δ13C), and radioactive carbon (14C) isotopic, geophysical, and hydrochemical data. The highest δD and δ18O ratios of water and the relatively young 14C ages in Group I and the lowest δD and δ18O in Group II indicated the short and long residence time in Group I and II, respectively. The electrical resistivity tomography (ERT) survey results also supported the fast rising through open fractures in Group I, while a relatively deep CO2-rich aquifer for Group III. Group II had high contents of Mg, K, F, Cl, SO4, HCO3, Li, and As, while Group I showed low contents for all elements analyzed in this study except for Al, which exceeded the World Health Organization (WHO) guideline for drinking-water quality probably due to the low pH. Meanwhile Group IV showed the highest Ca/Na as well as Ca, Fe, Mn, Sr, Zn, U, and Ba, probably due to the low-temperature dissolution of plagioclase based on the geology and the ERT result. The levels of Fe, Mn, and U exceeded the WHO guidelines in Group IV, while As in Group II. The different hydrochemistry suggests a distinct evolutionary process for each group. Group I seems to represent a fast discharge from the CO2-rich aquifer to a discharge point, experiencing a low degree of water-rock interaction, while Group II seems to represent a slow discharge with a high degree of water-rock interaction. GSB is a potential site for geological carbon storage (GCS), and injected CO2 may leak through various evolutionary processes given heterogenous geology as CO2-rich springs. The study result suggests that the combined use of pH, Na, K, Li, and Ca/Na are effective hydrochemical monitoring parameters to assess the leakage stage in silicate rocks in GCS projects. Besides, aluminum (Al) can be risky at the early stage of CO2 leakage, while Fe, Mn, U, and As at the later stage of CO2 leakage.

Groundwater Circulation in the Xianshui River Fault Region: A Hydrogeochemical Study

Water samples from rainfall, river, springs, and wells in the Xianshui River fault region near Xialatuo, China were collected during two sampling campaigns to investigate the complex groundwater circulation in the region. The major ions, stable isotopes, and four natural radium isotopes of the water samples were analyzed, and the results were utilized to identify different groundwater circulation depths. Most water samples excluding the one at a hot spring and the one at a borehole possess similar hydrochemical compositions and lower total dissolved solids (TDS), implying that their circulation depth is relatively shallow or that residence time is short. The sample at the hot spring has high TDS and high temperature as well as the high F concentration, inferring that it may circulate at a deeper depth. The sample at the borehole contains mixed hydrochemical characteristics of other samples. Three groundwater flow systems may exist in the study area: the shallow groundwater system recharged by precipitations and local groundwater flow, the deep groundwater system recharged by the regional groundwater flow, and the intermediate one between the above two systems. The finding of the three flow systems is supported by the δ2H and δ18O as well as the apparent radium ages of the samples. The δ2H and δ18O values at the intercept of the line formed by the shallow groundwater samples and the local meteoric water line (LMWL) are similar to those of modern precipitations. The δ2H and δ18O values at the intercept of the line formed by the deep groundwater samples and the LMWL show that it is probably recharged by relatively older precipitations. The 2H and 18O values of the borehole samples are between the above two intercept points. The deep-circulated groundwater with high temperature has longer apparent radium age than other water samples. The apparent radium ages of the shallow groundwater are similar but less than that of the deep groundwater. Groundwater at the borehole may circulate at a depth between the above two. The results of this study improve our understanding of the complex groundwater circulation and enable us to better protect and manage the groundwater resources in the region.

Impact of magnetic field strength generated by Halbach array on hard water for solar applications

The paper discusses about halbach array, the method of arranging permanent magnets in a specific manner. In halbach array, parmanent magnets are arranged in a way that magnetic field strength on one side of array increases while on the other side of the array, magnetic field almost gets nullified. The paper explains about the effect of that increased field strength on the TDS of hard water. Total dissolved solids (TDS) consist of inorganic salts such as magnesium, calcium, sodium, potassium, bicarbonate, sulphates chloride and other organic matters dissolved in water. The scaling in a pipe or health hazard makes it necessary to treat the hard water for its high TDS. CaCO3 and MgCO3 (calcium carbonate and magnesium carbonate) are sedimentation agents that are affected by the strong magnetic field and hence scaling is reduced. The test is performed by varying the field strength linearly along the water flow by changing the water flow rate.

Evolution of groundwater chemistry in coastal aquifers of the Jiangsu, east China: Insights from a multi-isotope (δ2H, δ18O, 87Sr/86Sr, and δ11B) approach

Groundwater salinization is currently a very serious and challenging issue in many parts of the world. With an increasing demographic pressure and remarkable changes of water and land uses over the last decades, the multilayer coastal aquifer system of Jiangsu province, east China, was affected by increasing salinization. In this study, we investigate the groundwater salinization process and the salinity sources of the aquifer system in Nantong area (southern part of the Jiangsu coastal plain) using a multi-isotope (δ2H, δ18O, 87Sr/86Sr, and δ11B) approach. The results show that the TDS (total dissolved solids) values in most deep groundwater samples are generally lower than those of the shallow groundwater samples. The TDS of both shallow and deep groundwater increase from western Nantong (inland) to the eastern coastal region of the Yellow Sea. The chemical types transform from Ca-Mg-HCO3 or Mg-Ca-HCO3 to NaCl. The stable hydrogen and oxygen isotopes signatures of the groundwater samples indicate that local precipitation likely acts as the main recharge source of both the shallow and deep confined groundwater systems. The deep groundwater shows more depleted isotopes, suggesting recharging by the precipitation under a cold climate before the Holocene period. The shallow groundwater features heavier water isotopes, indicating recharging source from recent precipitation under a warm climate. The variations in δ11B and 87Sr/86Sr of groundwater samples can be explained by the changes of solute sources. In the inland region (western Nantong), shallow groundwater with higher TDS is mainly caused by evaporation-induced concentration, whereas in coastal areas, seawater intrusion exerts a major influence on the chemical composition of the shallow groundwater.Our results show that that seawater intrusion mainly occurs in eastern and southeastern Nantong area. We also find that hydraulic connection between shallow and deep groundwater is strengthened by continuous overexploitation, and deep groundwater is mixed with shallow groundwater at some points. The mixing between upper saline water and deep freshwater, together with water-rock interactions, likely explain the observed low salinity in deep groundwater in coastal areas. Overall, with growing observations of salty seawater intrusion in the estuary region of the Yangtze River, future efforts are needed to prevent further seawater intrusion as sea level rises and groundwater table declines. In this context, our findings provide key information for groundwater management in other coastal aquifers, east China.

DISSOLUTION BEHAVIOR OF CORROSIVE ANIONS FROM SABKHA SOIL SOUTHERN KUWAIT UNDER LONG TERM LEACHINGA

Corrosive anions leaching from sabkha soil due to continuous surface or subsurface flow, to ground water can create a corrosive environment for underground structures. This study aimed to investigate the amount of leached chloride (Cl−) and sulfates (SO42-) corrosive anions in terms of quantity and rate as a ratio of Total Dissolved Solids (TDS). In this study representative Sabkha soil sample from southern Kuwait was leached for 40 pore volumes with distilled water. It was determined that corrosive anions, chloride and sulfate, contributed to the high effluent TDS levels in the leachate. For TDS, the corrosive anions dissolution was over 50% in first leached pore volume, increasing to over 75% in the final stages of leaching. Results also showed a distinct tendency of reduction with pore volume in the concentration of SO4-2and CI-anions.These findings will help allow the prevention of underground structure corrosion by evaluating the numerical criteria for particular anions such as chloride and sulfate. In establishing appropriate stabilization techniques, it is necessary to consider anion dissolution as one of the prime criteria.

Evaluation of groundwater geochemical characteristics and quality in the central and Northern Shaanxi Province, China

Groundwater is of vital importance to many aspects of ecosystem services, especially in the central and northern Shaanxi Provence, China,— an area covered by loess deposits and short of water resources. We studied the solute geochemistry and water quality of groundwater in this area to improve the understanding of hydrogeochemical processes in loess deposits area. The results showed that the average pH of groundwaters was 8.03 ± 0.36 (1 SD) with large ranges (324 − 83,379 mg/L) of the total dissolved solids (TDS). The cations and anions followed the order of Na+ > Ca2+ > Mg2+ > K+ > SiO2 and HCO3− > Cl− > SO42− > F− > NO3−. Most groundwater samples show the HCO3−–Na+–Ca2+ water type and a small number of samples the Na+–Cl− type. Irrigation water quality assessments showed that 40% of the groundwater has good water quality, 42% moderate water quality, and 18% (the upper reaches of Wuding River and Wei River) poor water quality with very high salinity. About 40% of groundwater samples were not suitable for drinking due to the high TDS, fluoride, sulfide, and chloride. Gibbs plot and stoichiometry analysis showed that carbonate weathering is the main source of groundwater chemistry in central Shaanxi Province while evaporite dissolution dominates in northern Shaanxi Provence. The loess weathering significantly influences the dissolved solutes of groundwater in the Loess Plateau. The ion-exchange between Mg2+ and Ca2+ in groundwater and Na+ in clay minerals and the deposition of carbonate minerals increased Na+ but decreased the Ca2+ in groundwater. Our research results improve our understanding of hydrogeochemical processes that affect the solutes chemistry of groundwater in the loess area and provide essential data to the global groundwater database.