Groundwater Bodies Research Articles

Physico-chemical and microbiological parameters of natural, industrial recycled water and its treatment

Background: Under conditions of anthropogenic impact, the chemical composition of water in surface rivers and groundwater bodies is subjected to pollution, which leads not only to a decrease in water quality, but also to an increase in the number of pathogenic and opportunistic bacteria. Aim: The purpose of this work is to study the physicochemical and microbiological parameters of natural and industrial recycled water before and after treatment with coagulants based on activated aluminum alloys. Materials and methods: As natural waters were analyzed: natural waters from water intake “Almaty SU”, “Medeu” tract, Zhaiyk river, from the well of experimental metallurgical production of IMOB. As recycled water was analyzed water taken from the water treatment unit of deep oil refining production. Turbidity was measured using HACH 2100Q turbidimeter and 2100Qis turbidimeter (USA). Cell morphology of microorganism cultures was studied by light microscopy using a MicroOptix MX-1150 (T) stereoscopic-sotrinocular microscope. Results: An effective and technologically simple method of obtaining aluminum polyoxychloride with the content of the main substance from 33 to 41.0% by Al2O3 and basicity from 55.1 to 66.5% has been developed. The method consists in dissolution of aluminum alloy activated by metal-activators (indium, gallium, tin) in the amount of 0.5–1.0 wt.% of each in 3% HCl. Physico-chemical and microbiological parameters of natural and industrial recycled water have been studied. The efficiency of the obtained aluminum polyoxychloride for treatment and conditioning of drinking water and industrial recycled water was evaluated. Conclusion: Unique alloys with high energy characteristics based on aluminum containing indium, gallium, tin from 0.5–1.0 wt.% have been created. The alloy has high activity in various oxidizing media (water, hydrochloric acid). A technologically simple method of obtaining aluminum polyoxychloride has been developed. Chemical and microbiological composition of natural and industrial recycled water has been studied. Coagulants based on activated aluminum alloys are effective in the processes of conditioning and purification of natural and recycled water from toxic compounds, have bactericidal activity, the level of gram-negative bacteria is reduced to 73%, gram-positive bacteria to 84% and to 96% of other groups of microorganisms. Fungi and yeasts (Mucor, Fusarium) were not detected after water treatment. Efficiency of water turbidity reduction reaches 90–99%, permanganate oxidizability up to 93%.

Groundwaterscapes: A Global Classification and Mapping of Groundwater's Large‐Scale Socioeconomic, Ecological, and Earth System Functions

AbstractGroundwater is a dynamic component of the global water cycle with important social, economic, ecological, and Earth system functions. We present a new global classification and mapping of groundwater systems, which we call groundwaterscapes, that represent predominant configurations of large‐scale groundwater system functions. We identify and map 15 groundwaterscapes which offer a new lens to conceptualize, study, model, and manage groundwater. Groundwaterscapes are derived using a novel application of sequenced self‐organizing maps that capture patterns in groundwater system functions at the grid cell level (∼10 km), including groundwater‐dependent ecosystem type and density, storage capacity, irrigation, safe drinking water access, and national governance. All large aquifer systems of the world are characterized by multiple groundwaterscapes, highlighting the pitfalls of treating these groundwater bodies as lumped systems in global assessments. We evaluate the distribution of Global Groundwater Monitoring Network wells across groundwaterscapes and find that industrial agricultural regions are disproportionately monitored, while several groundwaterscapes have next to no monitoring wells. This disparity undermines the ability to understand system dynamics across the full range of settings that characterize groundwater systems globally. We argue that groundwaterscapes offer a conceptual and spatial tool to guide model development, hypothesis testing, and future data collection initiatives to better understand groundwater's embeddedness within social‐ecological systems at the global scale.

A Review of Methods to Assess Groundwater Vulnerability to Pollution

Groundwater resources that are increasingly being cherished for most socioeconomic development are exposed to varied pollutant sources. Studies have shown that they are vulnerable to various impacts such as climatic change, human impacts and also pollution from seawater intrusion in coastal areas. The susceptibility of a groundwater body to pollution indicates extent to which its quality is at risk of being compromised by contaminants. Assessments of this vulnerability are classified based on scale (site, local, regional) or objective (such as risk management or protection zoning) and also distinguish between source and resource vulnerability maps, as well as specific and intrinsic vulnerability maps. Groundwater vulnerability assessment methods differ based on several factors, including the availability and spatial distribution of quantitative and qualitative data, the objectives and scale of the mapping, the costs of model development, and the particular hydrogeological characteristics of the aquifer under investigation. The National Research Council has classified these methods into three primary categories: process-based methods, statistical methods, and overlay/index methods. Among these, the overlay/index method is widely employed for conducting large-scale assessments of aquifer sensitivity and groundwater vulnerability. It is especially advantageous in developing countries due to the easily accessible data required for its implementation.

A new method to extract coal-covered area in open-pit mine based on remote sensing

ABSTRACT Coal is a prominent energy resource in China. Therefore, it is crucial to accurately extract the coal-covered areas. Taking Xinjiang’s Zhundong mining region as the study area, Landsat 8 OLI data were employed to assess the spectral curves of four typical ground objects, including vegetation, bare land, water body and bare coal. The Normalized Difference Bare Coal Index (NDBCI) and the Normalized Difference Coal Index (NDCI) were developed to extract coal-covered area. Higher-resolution Sentinel-2B data for the same period were used for verification, with extraction accuracy evaluated by five metrics including Kappa coefficient, Overall accuracy, Checking accuracy, Checking completeness and F1-score. The results of extracting coal-covered areas showed that (1) the NDBCI showed ‘internal fragmentation’ and the NDCI demonstrated ‘pixel overflow’ during the extraction process. Therefore, we determined the optimal thresholds −0.03 for NDBCI and 0.04 for NDCI. (2) NDBCI distinguished pixels with lower grey-scale values, such as water body, road and gangue. However, some dump zones and shed patches were misclassified. (3) NDCI generated clear boundaries and more complete interiors, and the dump zone and shed could be distinguished. However, some water body parts were misclassified as coal-covered areas. (4) Combined application of NDBCI and NDCI generated a ‘complementary’ effect better than both individual modes. Kappa coefficient, Overall accuracy and F1-score reached 0.95, 98.76% and 0.75, respectively. This study successfully extracted coal-covered areas by developing a remote sensing index based on spectral traits and a priori knowledge of the study area. The proposed combined extraction mode achieved high accuracy for rapid and reliable identification of coal-covered areas.

Interface and mixing zone between soil waters arising from upward and downward seepage - Part I: Homogeneous total density

Thin water lenses floating on top of the main groundwater body are important for many natural and agricultural systems, owing to their different properties in terms of chemical composition or density compared to the surrounding groundwater. In settings with upward seeping groundwater, lenses may form that have thicknesses ranging from tens of centimeters to a few meters, making them prone to changing conditions in the short (seasonal) or long term (climate change). Knowing their thickness, shape, movement and mixing zone width may help in managing these lenses.In a series of two papers, we present a mathematical description of the flow of water and transport of solute in a 2D cross-section between two parallel outflow faces and compare a simplified model to a complete model as described by the numerical code SUTRA. In this first paper of the series, we consider situations with a homogeneous density distribution. In the simplified model we employ the sharp interface approximation to obtain an expression for the stream function, the interface between the two types of water and the corresponding maximum lens thickness in steady state in the domain considered. This steady state description is used for travel time analyses and forms the basis for the transient analyses. For a typical example of oscillatory (e.g. seasonal) fluctuations in boundary conditions, we obtain expressions of the movement of the interface midway between two outflow faces by separating the problem into two timescales using the interface motion equation. This analysis provides insight into the importance of parameters on the vulnerability of water lenses under changing conditions, and may easily be extended to situations with abrupt or gradual changes in boundary conditions reflecting changes in land use or climate, respectively. Finally, we derive an analytical approximation of the mixing zone midway between the drains for steady state solutions, stepping away from the sharp interface approach. For a variety of examples, we validate the obtained expressions of the simplified mathematical model against the numerical model code SUTRA, which solves the fluid and solute mass balances explicitly.

Short high-accuracy tritium data time series for assessing groundwater mean transit times in the vadose and saturated zones of the Luxembourg Sandstone aquifer

Abstract. Among the manifold of environmental tracers at hand, tritium is the only one that can give information on groundwater age within the timescale of 100 years for the entire flow system, i.e., unsaturated and saturated. However, while in the Southern Hemisphere, a single water sample is sufficient for tritium-based young groundwater dating, several tritium measurements spanning multiple years are still needed in the Northern Hemisphere to disentangle the natural cosmogenic tritium input from that caused by the atmospheric thermonuclear weapons tests mainly carried out in the early 1960s. Although it is advised to focus tritium dating on sites where long chronicles of tritium data are available, in this study we tested the potential for short high-accuracy tritium data series (∼4 years) to date groundwater from 35 springs draining the Luxembourg Sandstone aquifer (central western Europe). We determined groundwater mean transit times using the lumped-parameter model approach in a Monte Carlo uncertainty estimation framework to provide uncertainty ranges inherent to the low number of tritium data at hand and their related analytical errors. Our results show that unambiguous groundwater mean transit time assessments cannot be determined solely based on such recent short tritium time series, given that several ranges of mean transit times appeared theoretically possible. Nonetheless we succeeded in discriminating groundwater mean transit times in the vadose and saturated zones of the aquifer through a stepwise decision process guided with several supplementary data. The mean transit time required for water to cross the vadose zone was estimated to be between 0.5±0.5 and 8.1±1.2 years depending on the spring, while for water to flow through the saturated zone, it varied from 5.7±2.4 to 18.9±4.6 years (median ± half of the 5–95 percentile range). Our findings are consistent with both the tritium measurements of individual springs and the hydrogeological context of the study area. We specifically corroborated the dating results using the known hydrogeological properties of the Luxembourg Sandstone aquifer, the hydrochemistry of the studied springs, and their discharge dynamics. When translated into water velocities (which average ∼12 and ∼170 m yr−1 for the vadose and the saturated zones, respectively), the tritium dating results mirrored the horizontal–vertical anisotropy of the aquifer's hydraulic properties caused by the bedded character of the Luxembourg Sandstone. In addition to improving our understanding of water transit times in the Luxembourg Sandstone aquifer, this study demonstrates how it is currently possible to use short tritium time series to date young groundwater bodies at new sites in central Europe.

Perspectives and Prospects for International Water Law in the ASEAN Region: Is There an ASEAN Way to Transboundary Water Cooperation Under International Law?

Around the world there are over 300 transboundary watercourses and around 500 transboundary groundwater bodies shared by two or more States. The Association of Southeast Asian Nations (ASEAN) region contains forty-one transboundary surface and groundwater bodies shared between ten ASEAN States and the five non-ASEAN States at its periphery. As transboundary water resources they are governed under international law found in a series of layers across a spectrum of bindingness (customary international law, global–regional–multilateral–bilateral agreements and non-binding instruments). Through an analysis of the international law relevant to the governance of transboundary water resources in the region, this study seeks to explore the ASEAN approach to transboundary water governance under international law. While this analysis finds that there is no uniform practice across the region, the paper concludes with possible paths forward for the legalization of transboundary water cooperation.

The effects of fertilizer pretreatment on nitrogen cycling in an intensively managed temperate grassland

Effective nitrogen (N) management is essential for minimizing fertilizer nutrient losses and maximizing N use efficiency. This study, conducted over two years on permanent grassland sites in Schleswig-Holstein, Germany, explored the effects of urea treatment with a urease inhibitor and digestate acidification on N-cycling and yield performance in a temperate maritime grassland context. Micro plots within these grasslands received varying N rates via acidified (with sulphuric acid) or non-acidified digestate (biogas residues), urea treated with- or without urease inhibitor (N-(n-butyl) thiophosphoric triamide) or calcium ammonium nitrate. Parameters measured included dry and N matter accumulations, NH3 volatilization, N2O emissions, NO3--N leaching, methane (CH4), and total greenhouse gas (GHG) emissions from soils. The findings demonstrated that the acidified digestate consistently enhanced metabolizable energy (ME), N yields (up to 47 %) and the apparent N recovery (ANR). While the acidified digestate and treated urea concurrently reduced NH3 emissions, the treated urea did not significantly affect (p> 0.05) dry matter (DM) and N yields, ANR, or total GHG emissions. Thus, digestate acidification or urea N stabilization could effectively mitigate the environmental impact of forage grass production while maintaining higher or comparable yields. However, higher risks of pollution swapping to groundwater bodies may result from higher N input rates. Applying acidified digestate or stabilized urea N to grasslands at a 120 kg mineral N ha−1 rate offers a practical approach, yielding appreciable N and ME while minimizing N losses.

Методика оценки экономического ущерба подземным водам при эксплуатации гидротехнических сооружений

Introduction. The problem is that currently there are no standard indicators for the degree of groundwater contamination. As a rule, standard indicators for surface waters are taken as a criterion for assessing their pollution. However, as is known, the underground hydrosphere is a separate environment, and groundwater is a separate component of the environment. In addition, groundwater is a strategic reserve of clean fresh water for the population of the Russian Federation. Therefore, it is clear that the regulation of maximum permissible harmful effects on groundwater and maximum permissible discharges of harmful substances into groundwater bodies is currently extremely necessary. Due to the fact that there are no standard indicators, there is no economic regulation of the negative impact of economic activities on groundwater. And this impact is very significant. This has been proven by numerous long-term monitoring studies of the underground hydrosphere, which is under the influence, for example, of mining enterprises in the Urals Federal District. Materials and methods. This work uses hydrogeological (deposit groundwater regime and balance monitoring), geochemical, and geo-ecological (groundwater quality and pollution monitoring) research methods, as well as observation and statistical and cartographic data processing methods. The research is based on a large amount of accumulated data and signature fieldwork. Results and discussion. As is known, in 1998, Guidelines were developed for the development of standards for maximum permissible harmful effects on groundwater bodies and maximum permissible discharges of harmful substances into groundwater bodies. However, this technique did not find its application, either because of its imperfection, or because it was believed that groundwater is sufficiently protected from negative technogenic and anthropogenic influences, in comparison with other components of the environment and, therefore, is not regulated need. Now it is obvious that groundwater, just like other components (atmospheric air, soil, surface water) experience intense negative impact from human economic activity and they require their own standards and, of course, economic regulation of such impact. The authors of this article have significantly improved the methodology for developing standards for maximum permissible harmful effects (MPH) on groundwater bodies and maximum permissible discharges of harmful substances (MPD) into groundwater bodies. This method has been patented and on its basis, the article presents a new method for calculating economic damage to groundwater, developed and tested on the basis of our own research on two unique largest technogenic-mineral formations in the Middle and Southern Urals. Conclusion. The hydrodynamic method for calculating groundwater pollution and normatively permissible discharge underlies the methodology for assessing natural damage to groundwater from pollutants of technogenic-mineral formations. The methodology for assessing economic damage to the underground hydrosphere from sources of surface pollution is based on calculating fees for the discharge of pollutants within the limit and above the limit. Resume. Technogenic mineral formations intensively affect groundwater, which is an important resource in human life in the present and especially in the future. Therefore, their uncontrolled pollution is unacceptable, which predetermines the development of a methodology for assessing damage to groundwater. Suggestions for practical applications and directions for future research. The application of a methodology for assessing economic damage to groundwater during the operation of hydraulic structures initiates the development of effective measures for higher and more comprehensive extraction of minerals, treatment of industrial wastewater, and more careful design and construction of hydraulic structures.

Simultaneous remediation of ciprofloxacin and nitrate threats in groundwater through manganese redox cycling: Performance optimization, mechanisms, and potential for community assembly

The misuse of fertilizers and antibiotics by the agriculture and livestock industries in recent years has led to groundwater bodies facing the problem of co-contamination by ciprofloxacin (CIP) and nitrate (NO3−-N). In this study, a manganese recycling system using manganese (Mn) redox-synchronized denitrification microorganisms loaded with manganese oxides was implemented to achieve simultaneous CIP and NO3−-N elimination. The reactor was operated for 195 days, during which the optimal operating conditions were determined by adjusting various parameters. The study also investigated the removal of CIP and its impact on the microbial community under these conditions. The experimental results showed that 77.4 and 92.5 % removal efficiency of ambient NO3−-N (16.5 mgL−1) and CIP (1 mg L−1) was achieved at pH 6.5, hydraulic retention time (HRT) of 8 h and carbon/nitrogen (C/N) = 2, respectively. However, it was observed that increasing the ambient CIP concentration above 1 mg L−1 significantly inhibited the manganese cycling and denitrification processes. The role of biomanganese oxides (BMO) in the redox removal of CIP was confirmed by product characterization. In addition, high-throughput sequencing confirmed the symbiotic relationship between manganese-cycling flora in the reactor, as well as verified the expression of genes related to core functions such as nitrogen metabolism and manganese cycling.

Effects of Winery Wastewater to Soils on Mineral Properties and Soil Carbon

Winery wastewater (WW) is a high-volume biowaste and, in the context of Marlborough and New Zealand wineries, there is a growing recognition of the need to improve current WW disposal systems to mitigate negative environmental impacts. The application of WW to land is a low-cost method of disposal, that could significantly reduce the environmental risk associated with WW directly entering surface and groundwater bodies. This study analysed elemental concentrations in WW and soils from three Marlborough vineyards across their annual vintage to determine the loading rates of nutrients into WW and the subsequent accumulation effects of WW irrigation on receiving soils. The findings showed loading rates of approximately 1.8 t ha−1 yr−1 of sodium within WW and a significant increase in soil sodium concentration and pH, attributed to sodium-based cleaning products. A loading rate of approximately 4 t ha−1 yr−1 of total organic carbon was also identified within WW, however, significant losses in soil carbon, nitrogen, magnesium and calcium concentrations were identified. Focusing efforts to retain key nutrients from WW within soils could provide benefits to New Zealand’s wine industry, facilitating increased biomass production in irrigation plots, thereby increasing biodiversity and potentially generating incentives for vineyard owners to contribute to increasing biomass carbon stocks and offset agricultural greenhouse gas emissions.

Comparative Study of Groundwater Quality for Drinking and Irrigation Purposes in Selected Villages of Manipur, India

A comparative study was done to monitor the groundwater qualities, both for drinking as well as irrigation purposes in some villages of Imphal East district, Manipur, in the period of pre-monsoon and monsoon of 2021. Totally, fifteen (15) groundwater samples were collected and examined for some important parameters like temperature, pH, TDS, TH, TA, Mg2+, K+, HCO3-, Ca2+, CO32-, Na+, Cl-, NO3- and SO42-. The results revealed that all the groundwaters were slightly alkaline in nature and fall under freshwater category. In both the seasons, majority of the parameters for various groundwaters have found their values/ concentrations below its acceptable limits, as given by BIS and WHO. In pre-monsoon, 73.33% of groundwaters were found as ‘moderately hard water’ and 26.67% (hard water) whereas in monsoon, 60% (moderately hard water) and 40% (hard water). Dominant ions in both seasons were Na+ (sodium) and HCO3- (bicarbonate) for cations and anions respectively. In most of the samples of monsoon, values and concentrations of the studied parameters were observed to be greater/higher as compared to that of pre-monsoon. It was mainly due to the leaching out of the soluble salts in the earth’s crust by rainwaters and finally mingled with the groundwater bodies in the aquifers in monsoon season. WQI values showed that in pre-monsoon, 26.67% of groundwaters were found as excellent water, 66.67% (good) and 6.66% (poor) while in monsoon, 60% (good) and 40% (poor). For irrigation water qualities, the indices (RSC, SAR, %Na, PI and KR) were examined. In the overall, all the samples can be utilized for irrigation (agriculture) purposes in both seasons. Correlation co-efficient (r) values showed that in both the seasons, the TH of various groundwaters was mainly because of dissolved sulphates of Ca2+ along with Mg2+.

Long-term impact of wastewater effluent discharge on groundwater: Identification of contaminant plume by geochemical, isotopic, and organic tracers' approach

Infiltration of effluents from wastewater treatment plants (WWTP) into groundwater can be a source of Contaminants of Emerging Concern (CECs), such as pharmaceutical compounds, that are not fully removed during the treatment processes. A multi-tracer approach, based on hydrogeochemical, isotopic, and organic tracers, is applied in the Vistrenque Aquifer (Gard, France) to assess the dispersion of such unintentional plumes and its potential implication on groundwater quality for CECs in a small catchment area. In this area, a point source of WWTP effluent causes contaminant infiltration and unintentional transfer to the aquifer. This strong impact of an urban effluent was revealed from the Br/Cl ratio, boron concentrations and δ11B isotopic signature of the groundwater in the direct vicinity of the infiltration point. With increasing distance from that point, dilution with groundwater rapidly attenuates the urban signal from these hydrogeochemical and isotopic tracers. Nevertheless, a gadolinium anomaly, resulting from discharges of urban wastewater containing the contrast agents used for magnetic resonance imaging (MRI), highlights the presence of a wastewater plume further along the flow line, that comes with a series of organic molecules, including pharmaceutical residues. Monitoring persistent or reactive molecules along the plume provides a more detailed understanding of the transfer of CECs into groundwater bodies. This highlights the relevance of pharmaceutical compounds as co-tracers for WWTP plume delineation. The present multi-tracer approach for groundwater resource vulnerability towards CECs allows a more in-depth understanding of contaminant transfer and their fate in groundwater.

Occurrence and abundance of microplastics and plasticizers in landfill leachate from open dumpsites in Sri Lanka

This is the first attempt that investigate the abundance of plasticizers in leachate sediment in the scientific literature, alongside the debut effort to explore the abundance of microplastics and plasticizers in landfill leachate and sediment in Sri Lanka. Microplastics in sizes ranging from ≥2.0–5.0, ≥1.0–2.0, and ≥ 0.5–1.0 mm were extracted from the leachate draining from ten municipal solid waste open dump sites and sediment samples covering seven districts. Microplastics were extracted by density separation (Saturated ZnCl2) followed by wet peroxide digestion and the chemical identification was conducted by Fourier Transform Infrared spectroscopy. Plasticizers were extracted to hexane and analyzed by high-performance liquid chromatography. The total mean microplastic abundance in leachate was 2.06 ± 0.62 mg/L whereas it was 363 ± 111 mg/kg for leachate sediments. The most frequently found polymer type was polyethylene (>50%), and white color was dominant. The average concentration of bisphenol A (BPA), benzophenone (BP) and diethyl-hydrogen phthalate (DHEP) in leachate was 158 ± 84.4, 0.75 ± 0.16 and 170 ± 85.8 μg/L respectively. Furthermore, BP and DHEP in leachate sediment was 100 ± 68.3 and 1034 ± 455 μg/kg respectively. As landfill leachate is directly discharged into nearby surface and groundwater bodies that serve as sources of drinking water, the study highlights the potential concerns of microplastic and plasticizer exposure to the surrounding Sri Lankan community through consumption of contaminated drinking water. Therefore, there is a timely need of develop the effective waste management and pollution control measures to minimize the possible threats to both the environment and human health.

Coastal Groundwater Bodies Modelling Using Geophysical Surveys: The Reconstruction of the Geometry of Alluvial Plains in the North-Eastern Sicily (Italy)

The integration of various geophysical methodologies is considered a fundamental tool for accurately reconstructing the extent and shape of a groundwater body and for estimating the physical parameters that characterize it. This is often essential for the management of water resources in areas affected by geological and environmental hazards. This work aims to reconstruct the pattern and extent of two groundwater bodies, located in the coastal sectors of the North-Eastern Sicily, through the integrated analysis and interpretation of several geoelectrical, seismic and geological data. These are the Sant’Agata-Capo D’Orlando (SCGWB) and the Barcelona-Milazzo (BMGWB) Groundwater Bodies, located at the two ends of the northern sector of the Peloritani geological complex. These two studied coastal plains represent densely populated and industrialized areas, in which the quantity and quality of the groundwater bodies are under constant threat. At first, the resistivity models of the two groundwater bodies were realized through the inversion of a dataset of Vertical Electrical Soundings (VES), constrained by stratigraphic well logs data and other geophysical data. The 3D resistivity models obtained by spatially interpolating 1D inverse VES models have allowed for an initial recognition of the distribution of groundwater, as well as a rough geological framework of the subsoil. Subsequently, these models were implemented by integrating results from active and passive seismic data to determine the seismic P and S wave velocities of the main lithotypes. Simultaneous acquisition and interpretation of seismic and electrical tomographies along identical profiles allowed to determine the specific values of seismic velocity, electrical resistivity and chargeability of the alluvial sediments, and to use these values to constrain the HVSR inversion. All this allowed us to recognize the areal extension and thickness of the various lithotypes in the two investigated areas and, finally, to define the depth and the morphology of the base of the groundwater bodies and the thickness of the filling deposits.

Enhancing water balance assessment in urban areas through high-resolution land cover mapping: Case study of Debrecen, Hungary

Land cover (LC) mapping in urban areas is one of the core applications in remote sensing (RS), and it plays an important role in modern urban planning and management. In order to support up-to-date simplified water balance calculation, LC modelling needs to be developed for precise and high-resolution operations to monitor rapidly expanding urban areas. This study provides a spatial decision support tool for urban water balance calculations considering hydrological parameters at pixel scale. The study is aimed to create a high-resolution LC map for more precise water balance calculations to identify and link the most important parameters, such as crop coefficient, for estimating crop evapotranspiration, runoff coefficients, and infiltration rate. Meteorological data from 2016 to 2019 were involved in evapotranspiration estimation. The study site is Debrecen, a city in northeast Hungary with a population of about 200,000. By integrating Landsat 8 imagery, Google Earth (GE), and Corine Land Cover (CLC), a LC map of 30 m resolution was created with 81.2 % overall accuracy (OA) and a coefficient of kappa greater than 0.78. For the classification of Landsat 8, seven classes were assigned (forests, sealed surfaces, areas with crop cover, grassland, semi-sealed surfaces, bare ground and surface water bodies). Classification results were validated by 101 ground truth samples using other satellite images and aerial photographs. Water balance parameters (i.e. surface runoff, infiltration and evapotranspiration) were then defined and calculated at a pixel scale and for larger areas. The technique developed in this study can also be utilized in other urban areas.

Bioremediation of Sulfate in Water Environment: An Overview of Removal Pathways and Influencing Factors

Sulfate-laden wastewater generated from various natural and industrial activities, including mining, metallurgy, electroplating, and battery manufacturing and recycling, has the potential to contaminate both ground and surface water bodies. It is harmful to all forms of life and the environment. Thus, developing an efficient treatment system to address sulfate pollution is necessary. Biological sulfate reduction (BSR) involving sulfate-reducing bacteria offers a better removal of sulfate than conventional physicochemical methods. BSR offers various advantageous such as lower sludge production, removal and recovery of metals, and production of elemental sulfur. However, the performance of bioreactors depends on wastewater sources, microbes involved, and operating conditions. Currently, limited studies are available encapsulating the current state of the art of biological sulfate remediation aimed at optimization of bioreactor design and operation. Therefore, this paper attempts to provide a comprehensive review of the sources of sulfate, its health and ecological effects, microbes involved in sulfate reduction, and its removal pathways that would be beneficial for future bioreactor design. In addition, theoretical and practical aspects of influencing factors have been discussed. Considering the results of the reviewed articles, operating, and set-up conditions are recommended to obtain the higher sulfate removal. It includes dissimilatory sulfate reduction by mixed bacterial culture using sodium lactate as an electron donor with pH near about neutral, mesophilic conditions, COD/SO2−4 ratio of 0.67-1.7, ORP less than −100 mV, and lesser sulfide concentration. This overview helps to develop an effective strategy for bioremediation of sulfate and decreasing the sulfate-rich industrial effluent footprint.

Hydraulic characterization of Pwales aquifer in Malta Island preparatory for planning managed aquifer recharge (MAR) pilot plant

Whitin the aim to reduce the water demand by increasing water use efficiency and providing alternative water resources, and mainly to meet the demand of good quality irrigation water for agriculture, the Energy and Water Agency of Malta is planning to develop a Managed Aquifer Recharge pilot plant in Pwales Valley to improve the quantitative and qualitative status of the groundwater body. For this reason a detailed hydraulic characterization of the valley was carried out. Specifically, hydraulic properties of the rocks that constitute strata atop of the Pwales aquifer were determined by means of both laboratory measurements on samples and field test carried out in the studied area. The water retention and hydraulic conductivity functions, which relate the matric potential, ψ, and hydraulic conductivity, K, to the water content, θ, respectively, were measured using three experimental methods because each of them allows to obtain data points in a specific wet range. The water retention and hydraulic conductivity functions were measured on samples extracted from blocks of Upper Coralline Limestone formation, that hosts the aquifer, collected in three different quarries: Ghian Tuffieha, Mellieha and San Martin areas. The measured water retention and hydraulic conductivity data were fitted with LABROS SoilView Analysis software that allows to describe the functions and obtain the parameters which are crucial for modelling the water flow and transport processes in the critical zone. In addition, large ring infiltrometer test was carried out to determine the field saturated hydraulic conductivity, Kfs, and the average infiltration rate. Knowledge of the hydraulic characteristics of the Upper Coralline Limestone, completely missing in the scientific literature, allows developing a local groundwater-flow numerical model in order to better describe and understand how the water flows from the soil to the groundwater of the valley and visualize different environmental scenarios such as the potential effects of Managed Aquifer Recharge plant in the Pwales Coastal Groundwater Body.

Flowpath 2023 Conference

The issue 175/1 of Acque Sotterranee – Italian Journal of Groundwater presents contributions from the Flowpath 2023 Conference which was held in Malta between the 14th and 16th of June. The scope of Flowpath focused on ensuring that hydrogeology can play an important role in supporting the development of groundwater management and protection policies; on strengthening the knowledge and research initiatives on emerging challenges to the groundwater environment and to highlight research initiatives undertaken in the Maltese islands, and improve technical cooperation between Maltese and Italian hydrogeologists. Flowpath brought together in Malta almost 200 hydrogeologists from Italy, Malta and six other countries who together contributed to 8 keynote speeches, 42 oral presentations and 45 posters. In fact this edition includes three papers from the Flowpath conference, two of which highlight joint work undertaken by researchers from Italy and Malta in the characterization of groundwater bodies.

THYRSIS: A QGIS plugin for hydrogeological modelling

THYRSIS is a new opensource QGIS extension dedicated to hydrogeological modelling of flow and transport at multiple scales, from local to regional. Based on SpatiaLite databases and time-dependent mesh layers, it is fully integrated into QGIS and allows the building of hydrogeological models. The modelling is based on 1D unsaturated vertical columns, coupled with a 2D horizontal groundwater model. Groundwater flow models can be imported or directly created with THYRSIS using the OpenFOAM cfMesh or GMSH mesh builders. Simulations are performed with the OpenFOAM porousMultiphaseFoam solvers, and the results are displayed in QGIS through the mesh layers. THYRSIS can handle several types of water or solute input in multiple zones, which can be defined at the surface or underground. Water or solute input can also be defined over the whole study area and directly in the groundwater body, ignoring the unsaturated zone. THYRSIS can therefore simulate the effect of heterogeneous, transient infiltration and reproduce variations in piezometric levels, or the transport of matter in the subsurface, from the ground to groundwater outlets, in order to estimate groundwater concentrations. Numerous functionalities are proposed such as uncertainty management, as well as the calculation and display of isolines and mass balance, time-potential or time-concentration graphs.