Brackish Groundwater Research Articles

Solar-Driven Thin Air Gap Membrane Distillation with a Slippery Condensing Surface.

Membrane-based desalination is essential for mitigating global water scarcity; yet, the process is energy-intensive and heavily reliant on fossil fuels, resulting in substantial carbon emissions. To address the challenges of treating seawater, produced water, brackish groundwater, and wastewater, we have developed a thin air gap membrane distillation (AGMD) system featuring a novel slippery condensing surface. The quasi-liquid slippery surface facilitates efficient condensate water droplet removal, allowing for the implementation of a 1 mm thin air gap. This advancement has led to a 2-fold increase in permeate flux without lowering the thermal efficiency while preventing permeate flooding. Furthermore, the thin AGMD system, employing a cost-effective zirconium nitride/poly(vinylidene fluoride) (ZrN-PVDF) composite membrane, has been demonstrated for solar-driven desalination. Experimental results indicate that reducing the air gap from 2 to 1 mm enhances the permeate flux by 150%.

Chloride in the Chalk aquifer of East Anglia, UK, Part 1: Distribution of chloride in brackish and saline groundwater

The Chalk aquifer of East Anglia is heavily exploited as a groundwater source. During exploration and exploitation, it has become clear that some of the groundwater in the Chalk is brackish and unsuitable for drinking (>250 mg/l chloride). Data comprising chemical analyses of pumped water samples and borehole depth samples (> 900 results in total), and downhole geophysical surveys have been used to assemble maps of the distribution of chloride areally and with depth. Brackish or saline water is probably present at depth in the Chalk, even where shallow fresh water is present, over much of the area where Crag Group marine sediments have been deposited. The depth below surface at which brackish water is encountered varies between 50 to >100 m, and the elevation of the transition varies from +16 mAOD to below 91 mAOD. From its chemistry it is deduced that most of the brackish water is of ancient marine origin, but that there has been localised intrusion of modern seawater in coastal areas, especially around Ipswich. Saline water most probably entered the aquifer during Crag Group times (late Pliocene-early Pleistocene) and its chemistry has been modified subsequently. The most saline old water that has been encountered has full marine salinity.

Electrocatalytic Nitrate Reduction for Brackish Groundwater Treatment: From Engineering Aspects to Implementation

In recent years, nitrate has emerged as a significant groundwater pollutant due to its potential ecotoxicity. In particular, nitrate contamination of brackish groundwater poses a serious threat to both ecosystems and human health and remains difficult to treat. A promising, sustainable, and environmentally friendly solution when biological treatments are not applicable is the conversion of nitrate to harmless nitrogen (N2) or ammonia (NH3) as a nutrient by electrocatalytic nitrate reduction (eNO3R) using solar photovoltaic energy. This review provides a comprehensive overview of the current advances in eNO3R for the production of nitrogen and ammonia. The discussion begins with fundamental concepts, including a detailed examination of the mechanisms and pathways involved, supported by Density Functional Theory (DFT) to elucidate specific aspects of ammonium and nitrogen formation during the process. Furthermore, the integration of artificial intelligence (AI) and machine learning (ML) offers promising advancements in enhancing the predictive power of DFT, accelerating the discovery and optimization of novel catalysts. In this review, we also explore various electrode preparation methods and emphasize the importance of in situ characterization techniques to investigate surface phenomena during the reaction process. The review highlights numerous examples of copper-based catalysts and analyses their feasibility and effectiveness in ammonia production. It also explores strategies for the conversion of nitrate to N2, focusing on nanoscale zerovalent iron as a selective material and the subsequent oxidation of the produced ammonia. Finally, this review addresses the implementation of the eNO3R process for the treatment of brackish groundwater, discussing various challenges and providing reasonable opinions on how to overcome these obstacles. By synthesizing current research and practical examples, this review highlights the potential of eNO3R as a viable solution to mitigate nitrate pollution and improve water quality.

Direct-drive photovoltaic electrodialysis via flow-commanded current control

Renewable powered, brackish groundwater desalination is an underutilized resource in the developing world, where there are unreliable energy sources and reliance on increasingly saline groundwater. Traditional renewable desalination technologies require sizable energy storage for sufficient water production, leading to increased cost, maintenance and complexity. We theorize and demonstrate a simple control strategy—flow-commanded current control—using photovoltaic electrodialysis (PV-ED) to enable direct-drive (little to no energy storage), optimally controlled desalination at high production rates. This control scheme was implemented on a fully autonomous, community-scale (2–5 m3 d−1) PV-ED prototype system and operated for 6 months in New Mexico on real brackish groundwater. The prototype fully harnessed 94% of the extracted PV energy despite featuring an energy storage to water productivity ratio of over 99% less than the median PV desalination systems in literature. Flow-commanded current control PV-ED provides a simple strategy to desalinate water for resource-constrained communities and has implications for decarbonizing larger, energy-intensive desalination industries.

Zeotropic mixture as a working fluid for cascade Rankine cycle-based reverse osmosis: Energy, exergy, and economic analysis

This study investigates the cascade Rankine cycle coupled with a reverse osmosis system for brackish groundwater treatment. The proposed system integrates a steam Rankine cycle (SRC) and an organic Rankine cycle (ORC) in a looped configuration, utilizing solar energy as a heat source. Each Rankine cycle is coupled with reverse osmosis (RO) to produce approximately 1 m3/h of permeate from each RO system. The system is investigated with working fluid combinations from R1233zd(E), R1234ze(Z), and R1336mzz(Z). Through comprehensive energy, exergy, and economic analyses, the system's performance is evaluated with zeotropic mixtures compared to pure R1233zd(E). The results demonstrate reliable performance with zeotropic mixtures, particularly R1233zd(E)/R1234ze(Z) with a mass composition of 0.6/0.4, demonstrating the maximum ORC expander work output of 1.15 kW. Parametric analysis reveals remarkable performance under different ORC system parameters. Variations in SRC condensation pressure show a trade-off performance between SRC and ORC turbine work output. Exergy analysis reveals an increase in exergy destruction by evaporation-based ORC components and a reduction in exergy destruction by condensation-based components, emphasizing improved irreversibility during the condensation process. Economic analysis indicates a marginal impact on the overall system cost, with the treated water cost ranging from 0.891 to 0.919 $/m3.

Massive Ice Outcrops and Thermokarst Along the Arctic Shelf Edge: By‐Products of Ongoing Groundwater Freezing and Thawing in the Sub‐Surface

AbstractSubstantial seafloor morphological changes are rapidly occurring along the Canadian Arctic shelf edge. Five multibeam bathymetric mapping surveys, each partially covering a 15 km2 study area between 120‐ and 200‐m water depth, were conducted over a 12‐year time period. These surveys reveal that 65 new craters have developed between 2010 and 2022, averaging 6.5 m and reaching up to 30 m deep. Remotely operated vehicle investigations revealed massive ice outcrops exposed on two newly formed crater flanks. This ice is not relict subaerially formed Pleistocene permafrost because it is hosted in sediments which were deposited in a submarine setting post‐deglaciation. Low salinity porewater and sediment core ice samples with depleted oxygen isotopic compositions indicate waters with a meteoric signature are discharging and freezing in this area. These ascending brackish groundwaters are likely derived in part from thawed relict permafrost hundreds of meters under the continental shelf. They refreeze as they approach the −1.4°C seafloor, leading to the development of widespread, near seafloor, sub‐bottom ice layers. Conditions appropriate for ice melting also exist nearby where ice is exposed to seawater or warmed by ascending groundwater. Small variations in temperature and salinity lead to shifts between freezing of ascending brackish groundwater or melting of near seafloor ice layers. These conditions have produced a dramatic submarine thermokarst morphology riddled with multi‐aged depressions. Thermokarst geohazards may exist, unmapped, on other Arctic margins with groundwater channeled toward the shelf edge by a relict permafrost cap, and sufficiently cold shelf edge bottom water temperatures.

PSX-30 Drinking preferences of natural sources of brackish groundwater by yearling goats and sheep

PSX-30 Drinking preferences of natural sources of brackish groundwater by yearling goats and sheep

Enhancing the performance of Litopenaeus vannamei nursery and grow-out by modifying Mg/Ca ratios in biofloc systems using low-salinity groundwater of Kuwait Desert

Kuwait has one of the most arid climates in the world, with brackish groundwater that has excessively high hardness due to limestone-rich aquifers with suboptimal ionic compositions, high evapotranspiration, and scarce water sources for shrimp farming. The study aimed to assess whether increasing the magnesium to calcium (Mg/Ca) ratio through Mg-supplementation could enhance shrimp performance, despite the absolute magnesium concentration being higher than diluted seawater of the same salinity. The study comprised a 4-week nursery and an 8-week grow-out trial with Pacific White Shrimp (Litopenaeus vannamei) in low-salinity groundwater in a biofloc system. Experimental groups included a groundwater control (Mg/Ca ratio 0.49) and three different Mg/Ca ratios (about 1, 2 and 3) in three replicates. Postlarvae (0.02 g) and juveniles (0.54 g) were stocked at a density of 1250 and 250 m−3 in the nursery and grow-out trials, respectively, in 1,000 L tanks. In the nursery trial, the control exhibited a final weight of 0.174 g and a survival rate of 58.5%, which was significantly lower in comparison to all Mg+2 treatments, exceeding 0.215 g and 92.5%, with no significant differences between the three treatments. The grow-out trial revealed a proportional increase in growth rate with the Mg/Ca ratio, showing a significantly better performance in treatments with Mg/Ca ratios of 2.12 or higher. The Mg/Ca 2 treatment exhibited the best performance, with a survival rate of 70.8% and a yield of 2.89 kg m−3 of mean weight 16.3 g. The results showed that Mg/Ca ratios have an affect both survival and growth in postlarvae, but only growth in juveniles and larger shrimp. The study suggests that increasing the Mg/Ca ratio above 1.07 and 2.12 through magnesium supplementation can significantly improve shrimp growth in nursery and grow-out phases in low-salinity water. Additionally, the expression of immune-related genes such as prophenoloxidase (proPO), transglutaminase (TGase) and cytosol manganese superoxide dismutase (cMnSOD), and superoxide dismutase (SOD) activity within different Mg/Ca ratios were analyzed. The results revealed significant differences in gene expression and higher SOD activity in the Mg/Ca 2 treatment of the grow-out phase, suggesting that Mg/Ca ratio closer to seawater may enhance the immunity and antioxidant activity of L. vannamei in a low-salinity biofloc system. In conclusion, the study provides valuable insights for shrimp producers using groundwater with high calcium hardness. The findings emphasize the importance of Mg/Ca ratio, rather than the absolute Mg+2 concentration, in improving shrimp growth and suggest potential benefits for shrimp immunity and antioxidant activity in low-salinity environments.

Diverse carbon sources impact the biofloc system in brackish groundwater altering water quality, fish performance, immune status, antioxidants, plasma biochemistry, pathogenic bacterial load and organ histomorphology in Florida red tilapia

A 75-day rearing trial was completed to investigate the effectiveness of different biofloc systems (BFT) on the water quality, growth performance and health status of Florida red tilapia (FRT) grown in brackish groundwater (BGW). The trial consisted of the control and three types of BFT using different carbon sources (CS), starch (ST), rice bran (RB), and wheat bran (WB) in triplicate, expressed as BF-0, BF-ST, BF-RB, and BF-WB, respectively. Fish weighing 4.98 ± 0.01 g/fish were stocked in 250-L tanks at an initial stocking density of 25 fish. The findings demonstrated significant reductions in inorganic nitrogen by-product (NH3 and NO2) levels in all BFT groups compared to the control, with an increase in floc volume and floc nutritional value, in the BF-ST and BF-RB groups. Furthermore, fish in the BF-ST and BF-RB groups showed significant improvements in fish growth indices (final weight, weight gain, and FCR). Fish in the BFT groups showed significant improvement in kidney function indices and plasma lipids with no significant changes in liver enzyme activity compared to the control. Lower stress markers (glucose and cortisol) and higher digestive enzyme activity (lipase and protease), innate immune parameters and antioxidants were reported in fish of the BF-ST and BF-RB groups compared to the control fish. Histopathological inspection revealed that the BF-ST fish exhibited healthier livers and shared healthier intestines with BF-RB fish compared to the control group. In conclusion, RB is an appropriate CS with BGW for desert aquaculture due to its availability, inexpensiveness, and comparable outcomes with ST.

Screening the Performance of a Reverse Osmosis Pilot-Scale Process That Treats Blended Feedwater Containing a Nanofiltration Concentrate and Brackish Groundwater.

A two-stage pilot plant study has been completed that evaluated the performance of a reverse osmosis (RO) membrane process for the treatment of feedwater that consisted of a blend of a nanofiltration (NF) concentrate and brackish groundwater. Membrane performance was assessed by monitoring the process operation, collecting water quality data, and documenting the blended feedwater's impact on fouling due to microbiological or organic means, plugging, and scaling, or their combination. Fluorescence and biological activity reaction tests were used to identify the types of organics and microorganisms present in the blended feedwater. Additionally, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to analyze suspended matter that collected on the surfaces of cartridge filters used in the pilot's pretreatment system. SEM and EDS were also used to evaluate solids collected on the surfaces of 0.45 µm silver filter pads after filtering known volumes of NF concentrate and RO feedwater blends. Water quality analyses confirmed that the blended feedwater contained little to no dissolved oxygen, and a significant amount of particulate matter was absent from the blended feedwater as defined by silt density index and turbidity measurements. However, water quality results suggested that the presence of sulfate, sulfide, iron, anaerobic bacteria, and humic acid organics likely contributed to the formation of pyrite observed on some of the membrane surfaces autopsied at the conclusion of pilot operations. It was determined that first-stage membrane productivity was impacted by the location of cartridge filter pretreatment; however, second-stage productivity was maintained with no observed flux decline during the entire pilot operation's timeline. Study results indicated that the operation of an RO process treating a blend of an NF concentrate and brackish groundwater could maintain a sustainable and productive operation that provided a practical minimum liquid discharge process operation for the NF concentrate, while the dilution of RO feedwater salinity would lower overall production costs.

Phreatic Groundwater Quality Analysis Based on Physical and Chemical Parameters in Kuta Raja Sub-District

Phreatic groundwater, discovered easily around communities in the Kuta Raja Sub-district, is sourced from the subsurface and stored in saturated areas, where it flows naturally through seepage or jets. Therefore, this study aimed to analyze the quality of phreatic groundwater using physical and chemical parameters. Color, taste, smell, and temperature were the physical parameters analyzed, while chemical parameters tested included electrical conductivity value, acidity (pH), and hardness level. To conduct the experiment, a total of 50 samples were obtained using a random sampling method. Physical parameters were evaluated using the observational method. Test for groundwater hardness level was conducted at the Aceh Health Office's Health & Medical Equipment Testing Laboratory. The pH was measured using a pH meter, while electrical conductivity value and phreatic groundwater temperature were tested using a water quality checker. The results showed that the physical quality of groundwater was in good condition. Approximately 64% of the samples had characteristics of yellow, tasteless, and odorless. The temperature value was in the medium category (30°C-35°C). Additionally, the electrical conductivity value of 84% was in the medium class (1,200–2,500) brackish groundwater category. It was important to acknowledge that a groundwater pH value of 6.5–8.5 based on field measurements was in the normal class. The hardness level (CaCO3) of phreatic groundwater was evaluated using the Titrimetric method based on SNI Number 06-6989.12-2004. The test was conducted on 6 groundwater samples in terms of water flow and variations in electrical conductivity values. Based on observations, 4 samples were categorized as "hard" samples, while 2 were classified as “very hard”.

Deficit Irrigation of Forage Cactus (Opuntia stricta) with Brackish Water: Impacts on Growth, Productivity, and Economic Viability under Evapotranspiration-Based Management

Climate change significantly impacts agriculture and forage production, requiring the implementation of strategies toward increased water and energy use efficiency. So, this study investigated the yield of forage cactus (Opuntia stricta (Haw.) Haw) under different irrigation depths using brackish groundwater (1.7 dS m−1), whose management was based on reference evapotranspiration (ETo) estimated by the Hargreave–Samani (HS) and Penman–Monteith (PM) equations. The research was conducted in Independência, Ceará, Brazil, under the tropical semi-arid climate. A randomized block design in a 2 × 5 factorial scheme was employed, varying the ET0 estimation equations (HS and PM) and irrigation levels (0; 20; 40; 70; and 100% of total required irrigation—TRI). Growth, productivity, and water use efficiency variables were evaluated at 6, 12, and 18 months after treatment initiation. The economic analysis focused on added value, farmer income, and social reproduction level. The results showed no isolated effect of the equations or their interaction with irrigation depths on the analyzed variables, suggesting that irrigation management can be effectively performed using the simpler HS equation. Furthermore, there was no statistical difference between the means of 100% and 70% TRI as well as between 70% and 40% TRI for most variables. This indicates satisfactory crop yield under deficit irrigation. Dry matter productivity and farmer income at 12 months resulting from complementary irrigation with depths between 40% and 70% of TRI were significantly higher than under rainfed conditions. The 70% depth resulted in yields equivalent to those at 100% TRI, with the social reproduction level being achieved on 0.65 hectares in the second year.

Multi-period optimization of water planning for a sustainable agriculture: carbon footprint and water footprint assessment

Abstract The State of Qatar has undergone significant changes impacting water resources in recent years, with rapid population growth being a significant factor. The government has implemented several policies and initiatives to manage water resources effectively, including introducing a water conservation strategy investing in desalination plants and wastewater treatment facilities. However, the expansion of the agricultural sector has driven up demand for water resources, placing additional pressure on limited supplies. Effective decision-making processes are crucial to sustainable water resource management, particularly in water-scarce countries, and multi-period optimization is an important tool for such decision-making. This study presents a five-year period for multi-period optimization of water planning in the agricultural sector to consider short-term and medium-term dynamics. The aim is to minimize the carbon footprint associated with agricultural water allocation, and assess water pollution using the Water Quality Index grey water footprint indicator. The water budget considered includes desalinated water, brackish groundwater, and treated sewage effluent, while the agricultural sector comprises dairy, egg and poultry, red meat production, outdoor farming, and indoor farming. Considering the water conservation importance in the State of Qatar, the three levels of water stress that were considered are 0%, 25% and a base scenario carbon footprint-based water stress. The latter is calculated such that the improved scenario’s carbon footprint is lower than that of the base scenario while keeping a safe annual water stress. Results show that it possible to reduce the water stress from an unsafe average to as little as 13.7%. Similarly, the water pollution estimated using the grey water footprint method is significantly lower compared to the base scenario.

Unlocking groundwater desalination potential for agriculture with fertilizer drawn forward osmosis: prediction and performance optimization via RSM and ANN.

The agricultural sector uses 70% of the world's freshwater. As clean water is extracted, groundwater quality decreases, making it difficult to grow crops. Brackish water desalination is a promising solution for agricultural areas, but the cost is a barrier to adoption. This study investigated the performance of the fertilizer drawn forward osmosis (FDFO) process for brackish water desalination using response surface methodology (RSM) and artificial neural network (ANN) approaches. The RSM model was used to identify the optimal operating conditions, and the ANN model was used to predict the water flux (Jw) and reverse solute flux (Js). Both models achieved high accuracy, with RSM excelling in predicting Js (R2 = 0.9614) and ANN performing better for Jw (R2 = 0.9801). Draw solution (DS) concentration emerged as the most critical factor for both models, having a relative importance of 100% for two outputs. The optimal operating conditions identified by RSM were a DS concentration of 22 mol L-1, and identical feed solution (FS) and DS velocities of 8.1 cm s-1. This configuration yielded a high Jw of 4.386 LMH and a low Js of 0.392 gMH. Furthermore, the study evaluated the applicability of FDFO for real brackish groundwater. The results confirm FDFO's potential as a viable technology for water recovery in agriculture. The standalone FO system proves to be less energy-intensive than other desalination technologies. However, FO exhibits a low recovery rate, which may necessitate further dilution for fertigation purposes.

Treatment of highly iron-contaminated brackish groundwater by MF, UF, and NF membranes for potable water resource production: influence of operating parameters, comparative study, membrane fouling, and machine learning modeling

ABSTRACT The present investigation focuses on using commercially available MF, UF, and NF membranes to eliminate Fe from real groundwater. The impact of process parameters, including applied pressure, temperature, pH, time, and concentration, on flux and Fe removal% is investigated. Results of the permeation test confirm higher permeability for MF membranes (214.71 L/m2.h.bar) than that for NF (2.708 L/m2.h.bar) and UF (56.52 L/m2.h.bar) membranes. The FESEM-EDS characterization confirms the deposition of dominant foulant Fe particles over the membrane surface. At 2 bar applied pressure (temperature = 30 °C, pH = 6.13, and concentration = 6.62 ppm), MF, UF, and NF can eliminate 93.5, 90.2, and 100% Fe, respectively. However, UF and NF exhibit much lower fluxes (72.43 and 3.85 L/m2.h, respectively) compared to MF (317.13 L/m2.h) at the same process conditions. NF eliminates 100% Fe from start to end with rising pressure, while MF (62.16–100) and UF (87.09–100) show gradually improved removal rates. Above pH 6, all membranes demonstrate higher Fe rejection because the oxidation rate of ferrous iron increases at a high pH. With increasing concentration (6–500 ppm), Fe removal efficiency increases for NF (88.26–94.18%) but decreases for both MF (89.63–23.64%) and UF (27.66–14.4%). To validate experimental findings, five machine learning (ML) regression models are scrutinized using various statistical measures.

Reverse osmosis silica fouling control with reactive micromixing

Silica fouling is a major challenge in groundwater reverse osmosis (RO) desalination. Dissolved silica, upon concentration during RO, forms a difficult-to-clean glassy foulant layer on membranes, limiting recoveries from brackish groundwater desalination systems. Further, dissolved silica interacts strongly with organic matter to enhance fouling and degrade membrane performance. In this work, we demonstrate an innovative coating approach employing catalytic metal oxides on polyamide RO membranes using polydopamine (PDA) that greatly mitigates fouling and alleviates concentration polarization (CP). By injecting hydrogen peroxide (H2O2) into the feed, oxygen (O2) bubbles were formed through the catalytic disproportionation of manganese dioxide (MnO2). The produced O2 bubbles increased turbulence in the boundary layer, which reduced both CP and silica fouling. Fouling was further reduced in the presence of humic acid, likely because of enhancement of the catalytic action of MnO2 in the presence of humic acid. Compared to other silica scaling control methods, which require high energy consumption, the use of H2O2 to generate bubbles consumes much less energy. Overall, PDA-encapsulated catalytic MnO2 particles in the presence of H2O2 increased the effectiveness of thin-film composite desalination membranes without impacting their integrity in short-term tests, indicating its potential for improving energy efficiency in RO systems.

Spatio-temporal trends in long-term seasonal groundwater level of South-western Punjab using non-parametric statistical tests.

To manage groundwater resources and develop an action plan, it is crucial to understand the long-term behavior of groundwater level (GWL) fluctuations. In this study, Geographic Information System (GIS) and non-parametric statistical tests were applied for detecting long-term (1973 to 2020) spatio-temporal variations and trends in GWL from 137 observation wells evenly distributed across the south-western part of Punjab. This region has experienced significant changes in GWL over the decades. The non-parametric statistical tests included Mann-Kendall (MK), Sens's SlopeEstimator (SSE), and Innovative Trend Analysis (ITA). The study observed significant trends in GWL fluctuations before and after monsoon. The MK and SSE tests showed a statistically increasing trend in observation wells with about 65.7% and 67.2% increase before and after monsoon, respectively. The innovative trend analysis (ITA) also revealed a statistically increasing trend in observation wells with an increase of about 63.5% and 65.7% pre and post-monsoon season, respectively. The results indicate lowering of GWL in the northern districts of southwestern Punjab, while the southern districts experience rising GWLs. This discrepancy can be attributed to diverse agricultural activities and reduced over-exploitation of groundwater in the southern district due to soil salinity and the presence of brackish groundwater. These findings provide valuable insights into the dynamics of GWL in the studied region, highlighting notable trends associated with seasonal variations.

Hydrogeochemical characteristics of shallow groundwater and salinization evaluation in the coastal aquifers of Cangzhou, China

To investigate the hydrogeochemical characteristics of shallow groundwater and evaluate groundwater salinization state in Cangzhou, China, two sampling campaigns have been conducted. In summer, 33 groundwater samples, 3 seawater samples and 5 river water samples were collected. In winter, 22 groundwater samples were collected. The hydrochemical type was determined by the Piper diagram. Evolution mechanisms of groundwater were analyzed by the Gibbs diagram. The trend of de-salinization or salinization of groundwater was determined by the hydrochemical facies evolution diagram. The groundwater salinization grade was evaluated by both the seawater intrusion groundwater quality index (GQISWI) and the attribute recognition model based on entropy weight (ARMEW). The Piper diagram shows that Na+ is the dominant cation and Cl- is the dominant anion in shallow groundwater, and the groundwater in this area is mainly of Cl-Na type followed by Cl-Ca·Mg type. The evaporation-crystallization process has significant influence on the evolution of saline groundwater. In summer, most brackish groundwater exhibit compositions of the freshening stage with direct cation exchange, and most saline groundwater is mainly at the seawater intrusion stage with reverse cation exchange. In winter, compared to the summer season, more groundwater samples in the middle of study area exhibit intrusion trend, and without obvious Na-HCO3 facies. In summer, values of GQISWI range from 20.47 to 75.38 with an average of 59.31. The GQISWI gradually increases from east to west, denoting the degree of groundwater salinization is alleviated from coast to inland. In winter, values of GQISWI range from 54.47 to 79.09 with an average of 66.00, slightly higher than that in summer. The proportion of no salinization (Grade I), minor salinization (Grade II) and serious salinization (Grade III) of groundwater samples in Cangzhou identified by ARMEW is 3.0%, 21.2% and 75.8% in summer, respectively. In winter, the proportion is 9.1% for Grade II and 90.9% for Grade III. The GQISWI index shows the largest area of Grade II, and ARMEW presents the largest area of Grade III in both seasons. Compared with GQISWI index, ARMEW model gives more conservative evaluation results of groundwater salinization. The results provide useful information on the groundwater salinization status for the local area, and help for the management of groundwater resources in Cangzhou.

Uji Kualitas Air Tanah di Distrik Merauke Ditinjau Dari Parameter Total Dissolved Solid (TDS), dan Salinitas

Merauke District has a characteristic landscape in the form of swampy lowlands formed by sedimentation with low-quality brackish groundwater sources. This study aims to determine the water quality based on the parameters of total dissolved solid (TDS) and salinity in Merauke District. Groundwater samples came from 11 villages with sampling techniques using cluster random sampling techniques. The test results in the laboratory showed that water samples from Rimba Jaya village had the highest TDS value with levels of 5040 mg/l and water samples from Mandala village had the lowest TDS value with levels of 478 mg/l. In the salinity parameter of Rimba Jaya village also has the highest salinity value with 5.34 ppt while the lowest salinity value is found in Mandala village with 0.41 ppt. From the test results on the parameters of TDS and salinity can be concluded that the quality of groundwater in the Merauke District of Papua province is low and does not meet the requirements to be used as a source of drinking water based on the regulation of the Minister of health of the Republic of Indonesia number 492/Menkes/Per/IV/2010.

Recent Advances in Iron, Manganese and Ammonia Removal from Brackish Groundwater Using Membranes

Recent Advances in Iron, Manganese and Ammonia Removal from Brackish Groundwater Using Membranes