Total Dissolved Solids Concentration Research Articles

Low-Energy Desalination Techniques, Development of Capacitive Deionization Systems, and Utilization of Activated Carbon

Water desalination technology has emerged as a critical area of research, particularly with the advent of more cost-effective alternatives to conventional methods, such as reverse osmosis and thermal evaporation. Given the vital importance of water for life and the scarcity of potable water for agriculture and livestock—especially in the Kingdom of Saudi Arabia—the capacitive deionization (CDI) method for removing salt from water has been highlighted as the most economical choice compared to other techniques. CDI applies a voltage difference across two porous electrodes to extract salt ions from saline water. This study will investigate water desalination using CDI, utilizing a compact DC power source under 5 volts and a standard current of 2 amperes. We will convert waste materials like sunflower seeds, peanut shells, and rice husks into activated carbon through carbonization and chemical activation to improve its pore structure. Critical parameters for desalination, including voltage, flow rate, and total dissolved solids (TDS) concentration, have been established. The initial TDS levels are set at 2000, 1500, 1000, and 500 ppm, with flow rates of 38.2, 16.8, and 9.5 mL/min across the different voltage settings of 2.5, 2, and 1.5 volts, applicable to both direct and inverse desalination methods. The efficiency at TDS concentrations of 2000, 1500, and 1000 ppm remains between 18% and 20% for up to 8 min. Our results indicate that the desalination process operates effectively at a TDS level of 750 ppm, achieving a maximum efficiency of 45% at a flow rate of 9.5 mL/min. At voltages of 2.5 V, 2 V, and 1.5 V, efficiencies at 3 min are attained with a constant flow rate of 9.5 mL/min and a TDS of 500 ppm, with the maximum desalination efficiency reaching 56%.

Application of a reaction-based water quality model to the total dissolved solids concentration of the Pasig River.

With the goal to support effective water resource management, water quality models have gained popularity as tools for evaluating the distributions of pollutants and sediments. This work focuses on the application of the numerical solution of an advection-dispersion-reaction (ADR) water quality model for rivers and streams to a major Philippine waterway, the Pasig River. The water quality constituent is described by a system of reaction and advection-dispersion-reaction equations. The model and method are based on a previously used strategy where Guass-Jordan decomposition is applied to the matrix system and the resulting conservative form of the model is solved numerically using the fully implicit scheme and finite element method. The methodology is demonstrated by a case study in Pasig River involving the concentrations of total dissolved solids (TDS) obtained from the Department of Environment and Natural Resources (DENR) through the Pasig River Unified Monitoring Stations (PRUMS) report. Sensitivity analysis and parameter estimation are also applied to the model to assess which parameters influence the model output the most.

Analysis of Spatial and Temporal Variation of Water Quality: A Case Study of Kotagala Wetland, Nuwara Eliya, Sri Lanka

Water quality of wetland ecosystems is a critical concern due to its implications on human health and aquatic life. This study was conducted to assess the spatial and temporal variation of water quality in Kotagala wetland to understand its impact on water safety for domestic uses and ecosystem health. Water samples were collected (n = 70) from six inlets and the wetland outlet from November 2021 to August 2022, and analyzed for pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), total suspended solids (TSS), nitrate, and phosphate. The pH, EC, and nitrate showed significant correlations. Spatial clustering divided the monitoring sites into two clusters, as areas of higher and lower pollution levels. Discriminant analysis highlighted the significance of EC, pH, and nitrate concentrations in differentiating these clusters. Principal According to principal component analysis (PCA) 88.8% of the total variance of spatial variation in water quality was explained by the first two components. Temporal clustering following seasonal variations revealed the influence of rainfall pattern on water quality. EC, TDS, TSS, and nitrate concentrations emerged as the most important factors in this temporal categorization. In PCA, 76.8% of the total variance of temporal variation in water quality was explained by the first two components. Findings highlight the urgent need for sustainable strategies and policies to mitigate the impacts of human activities on wetland water quality, since water quality variations in the wetland was significantly impacted by direct human activities, and variations in rainfall trends in the area.

Spatial and temporal variations of dug well water quality in Korba basin, Chhattisgarh, India: Insights into hydrogeological characteristics

Comprehensive assessment of groundwater quality in mining-affected regions is crucial to sustainably manage water resources and protect public health and ecosystems. This study investigated the hydrogeochemical characteristics and water quality of 18 dug wells in the Korba basin, Chhattisgarh, India, an area heavily impacted by coal mining activities. Water samples were collected over three seasons (pre-monsoon, monsoon, and post-monsoon) and analyzed to determine physicochemical parameters, major ions, trace elements, and carbon content. Results revealed very high total dissolved solids concentrations ranging from 315 to 19,738 mg L−1. Nitrate levels surpassed the Bureau of Indian Standard (BIS) limit of 45 mg L−1 in over 50% of samples, reaching a maximum of 200 mg L−1. Fluoride concentrations in all samples exceeded the BIS limit (1.5 mg L−1), ranging from 1.5 to 15.2 mg L−1. The predominant water type was Ca-Mg-HCO₃, primarily influenced by rock-water interactions. Factor analysis indicated that both geogenic and anthropogenic processes influence pollution levels. Pollutant concentrations exhibited seasonal variations, generally peaking during the monsoon period. Temporal analysis from over six years revealed increasing trends for most parameters, indicating deteriorating water quality. Based on Water Quality Index values, all samples were classified as unsuitable for drinking, while assessments of irrigation water quality using various indices indicated that 61.11% of samples were suitable for agricultural use. The findings provide data to inform decision-making and public health protection in this heavily industrialized region and emphasize the urgent need for sustainable water resource management and pollution prevention strategies in the Korba basin to align with UN Sustainable Development Goals 3 (good health and well-being) and 6 (clean water and sanitation).

Impacts of illegal mining activities on water quality for irrigation and implications for public health: A case study of the Oda River in the Ashanti Region of Ghana

ABSTRACT This study evaluated the biological and physicochemical parameters of the Oda River, including the detection of heavy metals. To achieve this purpose, a quantitative experimental research design was employed. Twenty-four water samples were taken along the Oda River from Obeng ne Obeng, Abuakwaa, and Odaso communities. The samples were analysed in a laboratory, and the results were compared to the irrigation water quality standards from the Food and Agricultural Organization (FAO). The study found that the concentration of turbidity and total suspended solids exceeded the recommended standards of FAO, while the river's pH, electrical conductivity, and total dissolved solids concentrations were within permissible boundaries. Lead, cadmium, mercury, arsenic, and fluoride were present at concentrations lower than the recommended guidelines, whereas copper and cyanide were not discovered. However, iron concentrations exceeded the FAO guidelines. Escherichia coli concentrations in the Obeng ne Obeng were lower than the FAO irrigation standards but were higher in the Abuakwaa and Odaso. The Pearson correlation coefficient highlighted significant correlations between the physicochemical parameters. This paper concludes that unregulated mining activities may endanger vital water resources for irrigation, public health, food safety, ecosystems, and livelihoods.

Experimental research on biogenic methane generation pathway and microflora constraints based on in-situ gas-water-microbe

Biogenic coalbed methane (CBM), generated through the biodegradation process of coal organic matter, is a relatively clean and environment-friendly unconventional natural gas resource. To investigate the differences in microbial communities (bacteria and archaea) as well as their environmental influencing factors between the Permian Shanxi Formation (P1s) and Taiyuan Formation (P1t), we systematically collected in-situ CBM samples along with coalbed water and microbial samples from a representative biogenic CBM field – the Baode block locked in the Ordos basin in China. The relative content of biogenic CBM was quantitatively calculated while analyzing gas composition, stable isotope, ion content, and high-throughput sequencing analysis to discuss the generation pathway for biogenic CBM and environmental control factors affecting microbial community structure. The results indicate that P1s and P1t are mixed with early thermogenic gas and secondary biogenic gas genetic types within their respective CBMs. The average proportion for biogenic gas within current coal seams is approximately 62.24 % for P1s, while it reaches around 64.37 % for P1t. Water quality type primarily consists of Na-HCO3 type with total dissolved solids (TDS) measuring at approximately 1015.86 mg/L for P1s, whereas P1t exhibits Na-Ca-HCO3-Cl water type with TDS content reaching about 2314.85 mg/L. Combining dominant Methanobacterium species, along with Δ13C(CO2-CH4) ratios and δD(CH4) versus δD(H2O) indexes, represents the biogenic CBM primarily generated through the hydrogenotrophic methanogenesis pathway. The in-situ bacterial communities of P1s are mainly influenced by Ni, pH, and TDS. The archaeal communities exhibit higher sensitivity to environmental factors (such as Co, pH, Ni, and dissolved organic carbon) than bacteria. These findings hold significant implications for understanding the generation process of biogenic CBM in middle and low-rank coal areas.

Groundwater quality analysis in Hail region of northwest Saudi Arabia based on physicochemical investigation

The acquired groundwater data from seventeen wells were hydrochemically analyzed for Sulfate, Chloride, Ammonia, Nitrate, Nitrite, pH, EC (Electrical Conductivity), TDS (Total Dissolved Solids), total hardness, and total alkalinity concentrations and then compared to the national and international standards. The results range as follows: pH (6.65–8.26), EC (382–1214 μS·cm−1), Total hardness (72–310 ppm), TDS (258–775 ppm), Total alkalinity (54–138 ppm), Cl- (19–202 ppm), Ammonia (NH3) (0.0 to 1.5 mg/liter), Nitrate (NO3) (4.7 to 65.6 ppm), Nitrite (NO2) (0.007 to 0.05 ppm), and sulfate (SO4) (29–278 ppm). About 70.58 % of the study area’s groundwater samples have TDS levels below 500 mg/l, which are considered safe for drinking. The EC of the groundwater found that 100 % of the samples fall within the allowed level. Based on these results, the groundwater quality is suitable for drinking and irrigation purposes in Hail region. Hence, this research shows that using GIS and chemical analysis of groundwater could be useful tools for the decision-making process of local and international authorities and water resources management.

Occurrence and abundance of microplastics in surface water of Songkhla Lagoon.

Microplastic (MP) pollution is now a global critical issue and has been the subject of considerable worry for multiple various types of habitats, notably in lagoons which are coastal areas connected to the ocean. MPs are of concern, particularly because floating MP in surface water can be ingested by a number of marine organisms. There are several lagoons along Southeast Asia's coastline, but Songkhla Lagoon is Thailand's only exit with a rich biodiversity. To date, there has been little research undertaken on MP in this lagoon, so there is a pressing need to learn more about the presence of MP in the lagoon's water. We investigate MPs in the surface water of Songkhla Lagoon, Thailand. Sampling took place at ten stations in the lagoon during the wet season in December 2022 and the dry season in February 2023. Samples were digested with hydrogen peroxide to remove organic matter followed by density separation using saturated sodium chloride. MPs were visually examined under a stereo microscope to describe and determine the shape, size, and color. Polymer type was identified using a micro Fourier transform infrared (FTIR) spectrometer. Moreover, the in-situ of water quality of the surface water was measured using a multi-parameter probe. A Mann-Whitney U test was performed to investigate the variations in MP levels and water quality parameters between the wet and dry seasons. Correlation analysis (Spearman rho) was used to determine the significance of correlations between MP and water quality (p < 0.05). MPs were detected at all ten of the sites sampled. The most abundant MPs were small size class (<500 µm, primarily consisting of fibers). Five types of polymers were seen in surface water, including polyethylene terephthalate, rayon, polypropylene, polyester, and poly (ethylene:propylene). Rayon and polyester were the dominant polymers. Additionally, the most dominant color of MPs in the wet and dry season was black and blue, respectively. The mean contents of MPs in the wet and dry season were 0.43 ± 0.18 and 0.34 ± 0.08 items/L, respectively. The Mann-Whitney U test suggested a significant difference between water quality in the wet and dry seasons (p < 0.05). Correlation analysis (Spearman rho) indicated a negative significant difference relationship between the MPs and the values of total dissolved solid (TDS) in the wet season (r = -0.821, p = <0.05), revealing that the large amounts of MPs may possibly be dispersed within surface water bodies with low TDS concentrations. Based on the overall findings, MP pollution in the surface water of the lagoon is not found to be influenced by the seasonal context. Rivers flowing into the lagoon, especially the U-Taphao River, may be a principal pathway contributing to increased MP pollution loading in the lagoon. The results can be used as baseline data to undertake further research work relevant to sources, fates, distribution, and impacts of MPs in other coastal lagoons.

Chemical characteristics, formation mechanisms, and geological evolution processes of high-salinity coal reservoir water in the Binchang area of the southern Ordos Basin, China

The chemical characteristics of coal reservoir water are important for studying the formation and enrichment of biogenic coalbed methane (BCM). Based on geological and sampling test data, this paper studied the geochemical characteristics and formation mechanisms of high-salinity coal reservoir water (CRW) in the Jurassic Yan'an Formation of the Binchang area in the southern Ordos Basin. The results show that the TDS contents of the CRW in the Binchang area are between 7577.38 and 15,138.61 mg/L (av. 13,268.95 mg/L), which is high-salinity brackish water. The ion types of CRW are mainly Na+, Cl− and HCO3−, and the correlations between TDS and Na+ and Cl− are close to 1. The Piper trilinear diagram indicates that the evolution direction of the CRW is deep concentrated brine, and the hydrochemical type is the NaCl type. The 127I concentrations of CRW are between 285 and 484 μg/L, which are much higher than the values of 55.88 μg/L for seawater. The results of 129I dating show that the minimum age of the CRW in the study area is between 6.7 Ma and 39.97 Ma, which is much younger than the actual geological age of the Yan'an Formation. The hydrogen and oxygen isotope results show that the CRW in the study area experiences an apparent oxygen drift, indicating that the coal reservoir of the Yan'an Formation has good sealing and a long retention time for the CRW. The hydrodynamic factors show that the hydrodynamic conditions of the coal reservoir are weak, and the primary ions in the CRW originated from the dissolution of salt rocks. The main ion differentiation indices show that high-salinity coal seam water is mainly formed by evaporation, and the ion exchange between CRW and the surrounding rock and the alternating adsorption of cations in water are very weak. Evaporation and diagenesis lead to an increase in the contents of Na+, Cl− and I+ in coalbed water, which in turn leads to an increase in the total dissolved solids contents of CRW and its evolution toward concentrated brine. The genesis and evolution of the CRW in the study area are affected by the combination of the relationships among the paleoclimate, aquifers and aquifuges, and tectonic evolution processes. The CRW in the study area has experienced five evolution stages, i.e., sedimentary water and diagenetic water, high-salinity infiltration water, primary mixed water, paleoatmospheric precipitation recharge water, and secondary mixed water. The above understanding can provide a basis for studying the formation period and accumulation mechanism of BCM and provide a hydrogeological basis for water resource utilisation and pollution prevention and the control of high-salinity water.

Groundwater contamination modelling in Ayad River Basin, Udaipur

Groundwater, a vital freshwater resource catering to agricultural, domestic, and industrial needs, faces a pressing challenge of contamination due to escalating human activities. This study focuses on the Ayad River Basin in the Udaipur district of Rajasthan, employing the FEFLOW simulation code for the first time. A steady-state numerical model and a groundwater contaminant prediction model for total dissolved solids (TDS), nitrate, and fluoride were developed, simulating trends over the next five years with an accuracy exceeding 95%. The results reveal an eastward increase in TDS, nitrate, and fluoride concentrations, attributed to contamination from two waste disposal sites-Titadi and Baleecha. Titadi, operational for four decades until closure in 2010, retains residual waste over 32 thousand m2. The initiation of a new dumping ground at Baleecha by the Udaipur Municipal Corporation post-2010 exacerbates regional contamination. Nitrate contamination is particularly high in agricultural zones with excessive chemical fertilizer usage. Of the 27 scenarios tested, 23 support using the water for irrigation but would require treatment before using it for drinking. Recommendations include deploying a chemical sensor network for real-time data input into the web enabled FEFLOW model, real-time monitoring and alerts, and a mobile application providing personalized guidance on water usage and health risks in case of contamination. This study can be beneficial to decision-makers, who work on the policy and groundwater management strategies.

A Study on Impact of Agricultural Activities on the Groundwater Quality of Medchal Malkajgiri District, Telangana State, India

The main aim of the present study is to evaluate the impact of agricultural activities on the groundwater quality in the eleven selected village areas of Medchal-Malkajgiri district of Telangana State, India. Forty Groundwater samples were collected during pre-monsoon and post-monsoon. The groundwater samples collected were analyzed for key agricultural nutrients, including Nitrates (NO₃⁻), Phosphates (PO₄³⁻), and Potassium (K⁺), as well as various physico-chemical parameters such as pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Hardness (TH), Total Alkalinity (TA), Sodium (Na⁺), Calcium (Ca²⁺), Magnesium (Mg²⁺), Carbonates (CO₃²⁻), Bicarbonates (HCO₃⁻), Chloride (Cl⁻), Fluoride (F⁻), and Sulphates (SO₄²⁻). The analyses followed the American Public Health Association (APHA) Standard Methods for the Examination of Water and Wastewater. The results were then compared against the Bureau of Indian Standards (BIS) 2012 and World Health Organization (WHO) 1999 guidelines for drinking water quality. The analytical results reveal that nitrates are within the acceptable limit during pre-monsoon season but five samples (25%) were exceeding the acceptable limits in post-monsoon season. It clearly indicates that the agricultural activities may be affecting the quality of groundwater in the study area. The concentration of TDS, TA, HCO3– and Cl– are also showing higher values.

Hydrogeochemical characteristics, driving factors, and health risk assessment of karst groundwater in Southwest Hubei Province, China.

In South China, karst groundwater is an important water resource for industrial, agricultural, and drinking purposes. However, karst aquifers are highly vulnerable to pollution, leading to deteriorating karst groundwater quality and posing potential health risks to local residents. In this study, 22 groundwater samples were collected from a karst aquifer in the southwestern part of Hubei Province. The hydrogeochemical characteristics and their controlling factors were examined, and the potential health risks associated with groundwater pollutant concentrations in karst groundwater were assessed. The results showed that the groundwater is slightly alkaline with low chemical oxygen demand values, indicating good water quality. The groundwater facies type was identified as HCO3-Ca at most sample spots, showing low total dissolved solids concentrations. Substantial spatial variations in Na+, CO3 2-, and NO2 - concentrations were found, whereas spatial variations in the K+, Ca2+, Cl-, HCO3 -, and F- concentrations were small. In addition, the dissolution of gypsum deposits and magnesium carbonate sedimentary rocks at sampling sites resulted in groundwater facies types of HCO3•SO4-Ca and HCO3-Ca•Mg, with low total dissolved solids concentrations. The karst groundwater chemistry in the study area was mainly controlled by water-rock interactions, as well as by the dissolution of gypsum deposits and magnesium carbonate sedimentary rocks at specific groundwater sampling sites. The groundwater Cl- concentrations were mainly affected by atmospheric precipitation. NO3 - was mainly derived from atmospheric precipitation, domestic sewage, septic tanks, and industrial activities, whereas SO4 2- was derived from atmospheric precipitation, sulfate rock dissolution, and sulfide mineral oxidation. These results highlight the absence of potential human health risks of NO3 - and F- to infants, children, and adults, as their concentrations are below the corresponding regional background values. In contrast, the potential health risks of Cl- cannot be ignored, particularly for infants. This study offers scientific guidelines for protecting and allocating local groundwater resources.

Preliminary Assessment of Selected Physico-chemical Properties of Peat Water in Relation to Land Use Conversion in Leyte Sab-a Basin Peatland, Philippines

Tropical peatlands are unique wetland ecosystems that provide various ecosystem services such as carbon and water storage. However, these ecosystems have been significantly altered by anthropogenic activities. In this study, the impact of land use conversion on the selected physico-chemical properties of surface water in the Leyte Sab-a Basin Peatland was investigated. Surface peat water was collected from peat swamp forest, peatland converted to grassland and peatland under cultivation. The surface peat water temperature was measured on-site and the collected water samples were analyzed for turbidity, pH, dissolved oxygen (DO), nitrate (NO3-N), phosphate (PO4), and total dissolved solids (TDS). It was found that the physico-chemical properties of water such as temperature, pH, and TDS were significantly higher in disturbed land use (cultivation) areas. The direct relationship between the temperature of surface peat water to both phosphate and TDS suggests that increasing temperature brought by peatland conversion may directly lead to increasing phosphate and total dissolved solids concentration in water. Strong relationships were also found between TDS and phosphates as well as between pH and dissolved oxygen. Finally, the increasing trend of values of the examined peat water physico-chemical properties with land use disturbance (cultivation) indicates peatland degradation.

Electrocoagulation removal of COD and TDS from real municipal wastewater sourced from the Euphrates River using multipole arrangement

This study investigated the performance of the electrocoagulation (EC) process for removing organic pollutants, as measured by chemical oxygen demand (COD), and reducing total dissolved solids (TDS) from real municipal wastewater sourced from the Euphrates River. A systematic approach was followed, where initial control tests were conducted to identify the optimal electrode configuration, which was a multipole arrangement of aluminum electrodes.The independent operating parameters studied were electrolysis time (10–60 min), applied current (0.2–1.4 A), and mixing speed (50–250 rpm). The response surface methodology (RSM), facilitated by a Box-Behnken design (BBD), was employed to model and optimize the EC process. The developed mathematical models revealed that the COD removal efficiency, final TDS value, and energy consumption were strongly dependent on the coagulation process parameters.The results showed that under the optimized conditions of 60 min of electrolysis time, 1 A of applied current, and 50 rpm mixing speed, a maximum COD removal efficiency of 92.43 % was achieved. At these optimal values, the final TDS concentration was reduced to 1299 ppm. The energy consumption for the batch EC process was also determined, with the lowest value being 5.47 kWh/m3.The findings demonstrate the effectiveness of the electrocoagulation process, particularly when utilizing a multipole electrode arrangement, for the treatment of real municipal wastewater. The developed models and optimization approach can be used to predict the performance and determine the optimal operating conditions for similar wastewater treatment applications. Future research prospects include investigating the removal of other pollutants, integrating the EC process with other treatment technologies, and evaluating the long-term economic feasibility of the system.

EVALUASI SISTEM DAN DAMPAK LINGKUNGAN PENGELOLAAN AIR TERPRODUKSI PADA SUMUR X1 PT MGBI LAPANGAN WUNUT

PT Minarak Gas Brantas Inc.'s operations in the Wunut Field involve the production of waste in various forms, primarily liquid waste, with produced water being the most significant type. Proper management of this produced water waste is crucial to prevent environmental pollution and ensure economic and environmental sustainability. The company manages this waste by reinjecting it into the reservoir to prevent groundwater contamination. To ensure the effectiveness of this reinjection process, they have created a groundwater flow pattern map (flow net) at three locations near the injection well: LP1 in Keduung Boto Village, LP2 in Candi Pari Village, and LP3 in Candi Pari Village, all in Sidoarjo Regency. This helps in understanding the potential spread of pollutants in the soil and underground water, aiding in environmental pollution monitoring and managment.The groundwater from this area is used for various human activities like bathing, cooking, and washing. However, based on water quality standards outlined in Ministry of Health Regulation No. 2 of 2023, the produced water from Well X-1 in the Wunut Field does not meet the required TDS (Total Dissolved Solids) content standards due to a decline in hydrocarbon fluid production, resulting in a separator efficiency of 74,86%. Additionally, lab tests and flow net results indicate that the TDS levels in LP1, LP2, and LP3 do not meet the sanitation and hygiene water quality standards, suggesting potential seepage in these locations that could contaminate groundwater. Keywords: Oil; Gas Produced Water; Gas Separator Eficiency; Groundwater Flow

Research of fresh/salt water in Upper-middle Pleistocene (qp\(_{2–3}\)) in Bac Lieu Province

This study identified the relationship between Total Dissolved Solids (TDS) and Electrical Conductivity (EC) with the TDS = 0.6628*EC = 0.1706 correlation, in which the correlation coefficient is r = 0.984 and the Standard Error (±%) is 2.78%. The TDS content is determined by small relative error and a high correlation coefficient of the conductivity, which applies to calculate the TDS content of other groundwater samples in Bac Lieu Province. Also, the temperature difference in the electrical conductivity measurement affects the TDS content; thus, the study has determined that the temperature compensated constant between the electrical conductivity on the field and those at 25oC is 0.002953. According to the data and the analysis of the TDS content, the fresh-salt water distribution map of the qp2–3 aquifers has been established, and its boundary has been more detailed and standardized than in the previous study. In particular, TDS values range from 0.437 g/L to 2.0 g/L. The areas that contain brackish and salt water are distributed discontinuously, forming the saline zones in Loc Ninh, Phuoc Long communes in Hong Dan district; Phuoc Long, Hung Phu communes in Phuoc Long district; Vinh Hau, Vinh Binh communes in Hoa Binh district, and Thuan Hoa commune in Bac Lieu city. The saltwater area of the qp2–3 aquifers is about 398 km2, accounting for 16% of the study’s total area. The results fresh-salt water distributed mapping provide the environmental management institution with a comprehensive view of the distribution of fresh-salt water to propose effective groundwater exploitation policies.

Mechanism controlling groundwater chemistry in the hyper-arid basin with intermittent river flow: insights from long-term observations (2001–2023) in the lower Heihe River, Northwest China

The geochemical processes of groundwater in arid regions are generally influenced by both natural hydrological processes and human activities. However, impacts of water-rock interactions on groundwater recharge via hydrological processes, controlled by both intermittent river water flow and groundwater withdrawals, is still poorly understood. In this study, 327 groundwater chemistry datasets collected from the upper, middle (including Gobi and riparian zones), and lower regions of the Ejina Delta in Northwest China from 2001 to 2023 were analyzed. Our results revealed that the total dissolved solids (TDS) concentration of groundwater in Ejina Delta ranged from approximately 881.5 ± 331.6 mg/L in the upper regions to 1,953.6 ± 1,208.5 mg/L in the lower regions, with an increasing trend observed. Ecological water conveyance (EWC), recharging aquifer through intermittent river water flow, resulted in a decrease in TDS concentrations from 2001 to 2023 mainly in the upper region. While irrigation notably affected groundwater chemistry in the lower region, resulting in a substantial increase in groundwater salinity. Groundwater chemistry in the Middle Gobi region remained relatively stable over the study period. Generally, the hydrochemical composition shifted from the Na-Mg-SO4-HCO3 and Na-Mg-Ca-SO4-HCO3 types in the upper region to Na-Mg-SO4-HCO3 and Na-Mg-SO4-Cl types in the lower region, with Na-SO4-Cl predominant in the Middle Gobi. These shifts were likely be attributed to the interplay of water-rock interactions, coupled with evaporation-crystallization processes. Inverse modeling using PHREEQC revealed that in the upper-middle region, primary water-rock interactions involved calcite dissolution and the precipitation of dolomite, gypsum, halite, and sylvite salts, as well as cation exchange reactions (2NaX+Ca2+→CaX2+2Na+). In contrast, the hydrogeological system in the middle-lower region exhibited an opposite pattern of water-rock interactions. Overall, ecological water conveyance partially facilitated water-rock interactions during lateral groundwater flow, while irrigation disrupted the natural hydrogeochemical equilibrium, involving halite dissolution and opposite cation exchange reactions compared to other regions.

Exploring Innovative Applications of Evaporative Cooling for High-Total-Dissolved-Solids Produced-Water Treatment

Summary This research delves into the pioneering application of evaporative cooling (EC) to address the challenge of reducing total dissolved solids (TDS) in produced water generated during hydraulic fracturing operations in the Permian Basin. In this study, we used a meticulously designed laboratory-scale EC system comprising three cooling pads, a fan, a water reservoir, and a pump. Through a systematic series of experiments, both synthetic and authentic produced-water samples were treated, shedding light on the potential of this novel approach. The EC system efficiently processed untreated produced water, circulating it through the cooling pads, all while closely monitoring crucial variables such as inlet and outlet temperatures, relative humidity, and remaining water volume, utilizing a state-of-the-art temperature and humidity meter. Control experiments were systematically conducted to probe the influence of varying salinities, achieved by introducing NaCl into distilled water, encompassing a wide range from 0 ppm to 70,000 ppm. In addition, we extended our evaluation to real produced-water samples collected from diverse regions within the Permian Basin (Delaware, Northern Midland, and Southern Midland), reflecting the system’s capability to manage high salinity and the diverse impurities inherent to oil and gas production. A comparative analysis of energy consumption was undertaken, positioning EC against conventional thermal evaporation techniques. The findings revealed a compelling insight that differences in EC efficiency between synthetic and real oilfield brines were primarily attributed to the presence of sodium (Na+) and chlorine (Cl-) contents rather than the overall TDS concentration. Across all experiments, the system consistently achieved remarkable TDS removal efficiencies, hovering around the 100% mark for both synthetic and authentic produced-water samples. Moreover, the study unveiled a significant advantage of EC, as it proved to be significantly less energy-intensive when juxtaposed with conventional thermal evaporation methods. In addition, our experiments revealed that divalent ions like CaCl2 tend to lower the treatment efficiency compared to monovalent ions, adding a crucial dimension to our understanding of EC in water treatment. The EC system demonstrated remarkable efficiency, achieving nearly 100% TDS removal in both synthetic and real samples while being significantly less energy-intensive than conventional thermal evaporation methods. This research underscores EC’s potential as an effective, sustainable, and economical solution for high-TDS water treatment, with promising applications in industrial settings. The study also draws parallels between EC and air conditioning systems, suggesting its versatility in various industrial applications.

Economic assessment of a multistage surface-heated vacuum membrane distillation process for the treatment of hypersaline produced water

The treatment and disposal of hypersaline produced water remains a challenge, particularly for oil and gas producers in the Permian basin where production wells generate significant amounts of wastewater, and the traditional method of injecting wastewater into disposal wells is coming under increasing scrutiny. Here we investigate the viability of using solar energy to power a multi-stage, surface heated, vacuum membrane distillation (SHVMD) with energy recovery to treat hypersaline produced wastewater from Midland, Texas. Membrane distillation is a process that can desalinate waters with high total dissolved solids concentration, and when incorporated into a system with surface heating and energy recovery can achieve high water recovery rates. Model results show that a 6-stage SHVMD system with a 54.4 % water recovery rate and a gained output ratio (GOR) of 3.28 has the potential to be economically viable when used to treat hypersaline produced water in the Permian basin. Assuming energy costs of $0.03/kWhthermal and $0.12kWhelectric, we estimate a project net present value (NPV) of $225,525 and an internal rate of return (IRR) of 13.5 % when an air cooled condensor is used to cool the distillate and a NPV of $570,791 and IRR of 24.52 % when a liquid coooling source is available. SynopsisThis work presents a comprehensive economic assessment of utilizing a surface-heated membrane distillation system with heat recovery to treat hypersaline produced well water.

Assessment of surface and groundwater quality in Tikamgarh city, Madhya Pradesh, India

Surface water and groundwater are primary resources for communities living in arid and semi-arid regions. The expansion of industrial and agricultural practices has raised pressure on natural resources. Water quality assessment provides valuable information about potential of resources for intended uses. The correlation study was carried out on the physicochemical parameters of surface water and groundwater in the Tikamgarh city. The physicochemical parameters, such as pH, total dissolved solids (TDS), total hardness (TH), calcium (Ca2+), magnesium (Mg2+), total alkalinity (TA), sulphate (SO42-), fluoride (F-), iron (Fe), nitrate (NO3-), chloride (Cl-) and turbidity were analysed to determine correlation between parameters. The grab sampling technique was adopted to collect water samples from selected dug wells and reservoirs. The results of physicochemical parameters were fitted in the correlation coefficient equation to predict probable values of different parameters for selected locations. Results of the correlation study showed that calcium and TH are strongly correlated, followed by TH with chloride. However, Ca2+, TH, Cl-, TA, TDS, SO42-, and iron show a high correlation. The findings show that water quality can be managed by controlling TH and TDS concentrations through conventional and non-conventional treatment methods.