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Water shortages occur due to several factors, with drought being one of the biggest drivers. Another major environmental issue related to the contamination of freshwater systems worldwide is thousands of micropollutants, although they generally occur at low concentration levels. The provision of safe drinking water to the population in rural developing nations remains a problem, in particular when surface water and shallow wells or non-watertight headworks wells serve as sources of drinking water. Dramatically changing raw water qualities, floods and high rainfall events anthropogenic pollution, lack of electricity supply in developing regions demand new and adapted solutions for treatment and rendering water safe for distribution. Our study aimes to find another source of water supply using riverbank filtration (RBF). The RBF is a water treatment method that removes water from rivers by pumping wells into a nearby alluvial aquifer. Several physical, chemical, and biological processes that occur underground improve the quality of surface water and eliminate the need for traditional potable water treatment. Additional treatment techniques in this process include biological degradation, sorption, and filtration. Physical, chemical, and microbiological variables were used to assess the effectiveness of the RBF system in Upper Egypt. Our study proposes a workable water treatment strategy that replaces RBF treatment or pretreatment technique for high-quality Nile water to eliminate or reduce surface water pollutants without the use of chlorine.

In response to Egypt's escalating water scarcity and pollution, Riverbank Filtration (RBF) technology is emerging as an effective solution to enhance water quality and simplify drinking water provision. This study evaluates RBF at three sites in Upper Egypt by assessing hydrogeological conditions and water quality based on 36 parameters from 2022 to 2023. Findings indicate that RBF efficiently treats infiltrated river water, with all sites meeting turbidity and microbiological standards (Total Bacterial Count and Coliforms), achieving removal rates of approximately 90% and 99%, respectively. Despite these successes, challenges persist in reducing manganese to safe levels, with concentrations at Alsaayda site reaching 0.51 mg/L, over the drinking water safe limit of 0.4 mg/L. To address this, further post-treatment strategies are proposed to remove the excess manganese. A practical application of an Oxidizer at the Bani Murr groundwater treatment plant has demonstrated the effective removal of iron and manganese, bringing their levels down to safe drinking water standards. This case exemplifies a successful solution for iron and manganese removal. This research highlights RBF's potential in water treatment in developing countries, while emphasizing the need for supplementary measures to manage specific contaminants. [ABSTRACT FROM AUTHOR]

Water shortages occur due to several factors, with drought being one of the biggest drivers. Another major environmental issue related to the contamination of freshwater systems worldwide is thousands of micropollutants, although they generally occur at low concentration levels. The provision of safe drinking water to the population in rural developing nations remains a problem, in particular when surface water and shallow wells or non-watertight headworks wells serve as sources of drinking water. Dramatically changing raw water qualities, floods and high rainfall events anthropogenic pollution, lack of electricity supply in developing regions demand new and adapted solutions for treatment and rendering water safe for distribution. Our study aimes to find another source of water supply using riverbank filtration (RBF). The RBF is a water treatment method that removes water from rivers by pumping wells into a nearby alluvial aquifer. Several physical, chemical, and biological processes that occur underground improve the quality of surface water and eliminate the need for traditional potable water treatment. Additional treatment techniques in this process include biological degradation, sorption, and filtration. Physical, chemical, and microbiological variables were used to assess the effectiveness of the RBF system in Upper Egypt. Our study proposes a workable water treatment strategy that replaces RBF treatment or pretreatment technique for high-quality Nile water to eliminate or reduce surface water pollutants without the use of chlorine. [ABSTRACT FROM AUTHOR]

The study examines the impact of climate change on the example of the Danube as a drinking water base in the Budapest area. The drinking water supply provided by river bank filtration systems is exposed to more frequent water level fluctuations and temperature changes in the connected surface waters. Our goal was to identify the most critical periods within the year by evaluating the daily water level and water temperature data between 1943-2021 and 1947-2021, respectively. It is important to understand the severity and frequency of climatic changes influencing drinking water safety. This aim can be achieved by evaluating the identified risks. Furthermore, as these risks affecting drinking water safety change significantly within a year, attention is drawn to the important role of both residential and industrial water use patterns. The minimum level of water safety determined for the period of increased load is of indicative value, based on which it becomes necessary to develop appropriate action plans. Based on statistical methods, it has been previously identified that the average water level of the Danube showed a decreasing trend in addition to an increase in water temperature. In this paper, we demonstrate that the water level fluctuations and the temperature changes follow an annual pattern. By superposing these patterns in an additive risk matrix, critical periods can be determined and, therefore, play a significant role in the time planning of larger maintenance or investment tasks. The study did not aim to evaluate in detail the investigation of other ecological, economic, and social effects of climate change related to drinking water safety for reasons of scope. [ABSTRACT FROM AUTHOR]

Pharmaceuticals and personal care products (PPCPs) are found in most rivers facing sewage input worldwide. This study investigated the occurence of 116 PPCPs in the Elbe river in Dresden, Germany, as well as the removal efficiency at a riverbank filtration (RBF) site. The data obtained were compared with data from two additional surface water monitoring stations along the Elbe river operated by a state environmental agency. 21 PPCPs were frequently detected in all water samples with concentrations up to 1270 ng/L. Spatial occurrence and sociodemographic aspects are discussed. According to the European Guideline for Environmental Risk Assessment, carbamazepine, diclofenac, iomeprol and venlafaxine indicate a suspected risk for the aquatic environment but not for drinking water quality in the Dresden region. Water treatment using a combination of natural treatment techniques and post-treatment using activated carbon filtration and disinfection proved to be an efficient barrier to drinking water pollution by PPCPs.

Copyright of Österreichische Wasser- und Abfallwirtschaft is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Expanding urbanization, socioeconomic factors, and agricultural activities have led to contamination of the natural water resources in Iraq. The objective of this study was to assess the riverbank filtration (RBF) process in purifying the water of Al-Kufa River from pathogens. The riverbank filtration is a natural approach that helps in the enhancement of the quality of river water, and it is a relatively cost-effective, and sustainable process. This study utilized microbiological approaches to monitor the water quality of wells in comparison with river water. In Al-Kufa district of Al-Najaf governorate in Iraq, eight wells were constructed at different locations adjacent to Al-Kufa River. Total plate count, coliform count, fungal count, and fecal coliform count were among the microbiological parameters tested. The findings of the current study showed a difference in the pathogen count between the wells and river water, but the riverbank filtration process did not meet the World Health Organization guidelines. From this, we concluded that, if the pumping well is continuously running, RBF as a preliminary treatment of surface water would be a promising and potentially viable application in purifying water supply. Finally, in future RBF process is supposed to be taken into consideration to protect the security of water supply from waterborne pathogens.

35-40% of Hungary's drinking water supply is based on riverbank filtered water bases. In addition, Budapest's water supply relies heavily on the riverbank filtered water bases located along the Danube. The research goal of the project "Drinking water: multidisciplinary assessment of secure supply from the source to the consumers" is the complex examination of two selected water bases, as well as the related water production structures and water distribution network from the Danube to the consumer. The two selected area was the Surány water base (east from Budapest), and the Ráckeve water base (south from Budapest). One of the sub-tasks of the project is the examination of the processes taking place between the Danube and the production wells, which is carried out by the staff of the Institute of Water Resources and Environmental Management of the University of Miskolc. In this study, we would like to present the results obtained during the field measurement campaign related to the Surány water base from the two selected project sample areas. With the help of field measurements, we can get an image of the subsurface flow conditions, and we can follow the effect of the Danube river. Our research can help us to build and calibrate a hydrodynamic model and to understand the operation of this natural purification system. [ABSTRACT FROM AUTHOR]

River bank filtration (RBF), as one of the sustainable natural treatment techniques, can provide risk-free drinking water supply to rural villages where piped water supply through conventional treatment schemes is very expensive. The main purpose of this paper is to report the results of a RBF production well implemented in a complex hydrogeological setting under the ephemeral Varaha river influenced by the saline coastal aquifer in the Visakhapatnam district of Andhra Pradesh (India) for the supply of drinking water to the nearby rural habitats that have no organized water supply. To understand and identify the hydraulics of the river–aquifer exchanged water, particle tracking analysis to determine the travel times of river water path lines, capture zones, the proportion of bank filtrate and river water, and groundwater into RBF production well consequent to pumping were carried out using modular finite difference groundwater flow model (MODFLOW) in conjunction with a particle-tracking model for MODFLOW (MODPATH). The river–aquifer and well field interaction were studied by developing a two-dimensional two-layer groundwater flow model with a partially penetrating well in an unconfined aquifer. The flow modeling simulation results together with MODPATH particle tracking analyses revealed that the installed RBF production well could yield about 61% river water through bank filtration and the remainder from the groundwater. The flow model was also used to optimize the pumping duration from the RBF production well without compromising the water quality of the bank filtrate water. The optimum pumping duration was estimated to be 5 h a day at the rate of 31.2 m3/h from continuous pumping during the monsoon period. The performance and quality of the bank filtrate from the well demonstrated that the RBF technique could also be a potential and viable approach for the supply of safe drinking water from an ephemeral river-induced bank filtrate influenced by the saline coastal aquifer. River bank filtration (RBF), a process to extract river water and groundwater through RBF wells, is one of the sustainable natural treatment techniques successfully providing risk-free drinking water supply in many urban, periurban, and rural areas in different countries. In India, it is gaining popularity, particularly in rural clusters where piped water supply through conventional treatment schemes has a remote chance of being effective. RBF wells are very effective in removing suspended particles, pathogenic compounds, and microorganisms present in the source water. The quantity of RBF water depends on the user requirements; for a town with a series of RBF wells or a small village using a single RBF well, RBF techniques can be employed. For establishing RBF wells in coastal regions, extra care would be required to fix the pumping rate and its duration to avoid mixing of saline with fresh water. The present study demonstrates the successful implementation of a RBF well on an ephemeral river (Varaha river in Andhra Pradesh State, India) in a saline coastal aquifer. The RBF technique can be employed to any other river reach or waterbody in the region where there is a need for potable water supply with minimum water treatment cost. [ABSTRACT FROM AUTHOR]

In drinking water supply, riverbank filtration (RBF) is an efficient and cost-effective way of eliminating pathogens and micropollutants using a combination of biotic and abiotic processes. Microbial communities in the hyporheic zone both contribute to and are shaped by these processes. Microbial water quality at the point of consumption is in turn influenced by the source water microbiome, water treatment and distribution system. Understanding microbial community shifts from source to tap and the factors behind them is instrumental in maintaining safe drinking water delivery. To this end, microbial communities of an RBF-based drinking water supply system were investigated by metabarcoding in a one-year sampling campaign. Samples were collected from the river, RBF wells, treated water, and a consumer's tap. Metabarcoding data were analysed in the context of physicochemical and hydrological parameters. Microbial diversity as well as cell count decreased consistently from the surface water to the tap. While Proteobacteria were dominant throughout the water supply system, typical river water microbiome phyla Bacteroidota, Actinobacteria, and Verrucomicrobiota were replaced by Nitrospira, Patescibacteria, Chloroflexi, Acidobacteriota, Methylomicrobilota, and the archaeal phylum Nanoarcheota in well water. Well water communities were differentiated by water chemistry, in wells with high concentration groundwater derived iron, manganese, and sulphate, taxa related to iron and sulphur biogeochemical cycle were predominant, while methane oxidisers characterised the more oxic wells. Chlorine-resistant and filtration-associated taxa (Acidobacteria, Firmicutes, and Bdellovibrionota) emerged after water treatment, and no potentially pathogenic taxa were identified at the point of consumption. River discharge had a distinct impact on well water microbiome indicative of vulnerability to climate change. Low flow conditions were characterised by anaerobic heterotrophic taxa (Woesarchaeales, Aenigmarchaeales, and uncultured bacterial phyla MBNT15 and WOR-1), implying reduced efficiency in the degradation of organic substances. High flow was associated the emergence of typical surface water taxa. Better understanding of microbial diversity in RBF water supply systems contributes to preserving drinking water safety in the future changing environment. [ABSTRACT FROM AUTHOR]

Expanding urbanization, socioeconomic factors, and agricultural activities have led to contamination of the natural water resources in Iraq. The objective of this study was to assess the riverbank filtration (RBF) process in purifying the water of Al-Kufa River from pathogens. The riverbank filtration is a natural approach that helps in the enhancement of the quality of river water, and it is a relatively cost-effective, and sustainable process. This study utilized microbiological approaches to monitor the water quality of wells in comparison with river water. In Al-Kufa district of Al-Najaf governorate in Iraq, eight wells were constructed at different locations adjacent to Al-Kufa River. Total plate count, coliform count, fungal count, and fecal coliform count were among the microbiological parameters tested. The findings of the current study showed a difference in the pathogen count between the wells and river water, but the riverbank filtration process did not meet the World Health Organization guidelines. From this, we concluded that, if the pumping well is continuously running, RBF as a preliminary treatment of surface water would be a promising and potentially viable application in purifying water supply. Finally, in future RBF process is supposed to be taken into consideration to protect the security of water supply from waterborne pathogens. [ABSTRACT FROM AUTHOR]

Riverbank filtration (RBF) is an affordable technique to provide drinking water with adequate quality. The ultimate objective of this study is to facilitate the transferability and application of this sustainable technique in Egypt. In this work, a numerical model was constructed using Groundwater Modeling System (GMS) to study the effect of four design parameters on the RBF performance parameters (i.e., river filtrate portion and travel time) with the aid of MODPATH and ZONEBUDGET. The design parameters were: (1) the pumping rates of the RBF wells, (2) number of operating wells, (3) distance between wells and the river, and (4) the spacing between wells. This study was focused on the hydraulic aspects of the technique. The results demonstrated that: (1) the river filtrate portion exceeds 75% regardless of the design conditions, and (2) the hydraulic performance of the RBF technique is highly controlled by the production capacity of the wells and their positions relative to the surface water systems; the spacing between wells has a minimum effect. Two equations were developed to estimate the river filtrate portion and minimum travel time as functions of pumping rate and distance between the pumping well and the river. HIGHLIGHTS Hydraulic aspects of riverbank filtration.; Impact of design parameters on river filtrate portion and travel time.; The relation between over-pumping and river filtrate portion.; Multi-regression analysis for RBF performance.;

Riverbank filtration (RBF) consists of green drinking water production in many regions and is used as a pre-treatment phase. This study investigates the performance of the RBF in the Nile delta, Egypt, for climate change and population growth scenarios of 2030, 2040, and 2050. This study presents a new method for predicting the sharing of riverbanks considering three cases: i) the river stage controlling the water levels in the river, ii) increasing RBF pumping, and iii) changing the groundwater levels. This last scenario is achieved by changing the general head in the MODFLOW model. The results showed that RBF sharing (RBFS) is a proportion of the river leakage inflow, in which the decrease of the river stage due to the influence of climate change reduced the river leakage inflow and RBFS. In addition, increasing RBF pumping, decreasing RBF pumping, and lowering the groundwater levels due to the increase in the future drinking water pumping for the population growth increased the river leakage inflow and RBFS. Finally, combining the three cases decreased RBFS in the coming years of 2030, 2040, and 2050, respectively, due to more groundwater sharing than the river inflow. The results show that the water budget is a good tool to investigate RBFS compared with MT3D results. This technique can reduce the cost of water quality collection and analysis; moreover, it will help with the estimation of RBF and save time compared with solute transport modeling.

The removal of linear alkylbenzene sulfonate (LAS) from river water was investigated using laboratory batch and column adsorption experiments to simulate and characterize critical geoenvironmental factors during riverbank filtration (RBF), including fine content, grain size (d50) of aquifer soil, soil bed depth, and detention time. The study examined nine distinct types of aquifer soil. Pseudo-1st-order, pseudo-2nd-order, and intra-particle diffusion kinetic equations were used to examine the kinetic data. The adsorption kinetics were found to be consistent with all kinetic models (R2 > 0.9). For each of the nine adsorbents, a column study was conducted and the logit method was used to calculate the different associated parameters. The assessment of efficacy under varying experimental conditions of empty bed contact time (EBCT) and bed depth, revealed that, an increase in EBCT and bed depth resulted in increased exhaustion time. From both batch and column kinetic study, it can be observed that rate of adsorption is higher for soil having highest fine content as well as for soil having smaller particle sizes. According to field data collected at three river bank filtration sites, the removal of LAS ranged between 44 and 88%, depending on the geoenvironmental factors' aquifer conditions and the season of study. The study established the critical role of geoenvironmental factors in LAS adsorption, which will aid in the identification of suitable aquifer site conditions for the new RBF system. [ABSTRACT FROM AUTHOR]

Riverbank Filtration (RBF) Technology has been found to be a safe, renewable, sustainable, and cost-effective drinking water treatment or pretreatment technology. The Egyptian government has recently turned to riverbank filtration to conserve drinking and industrial water at a lower cost and higher efficiency. The study aims to assess the hydraulic performance of the riverbank filtration system in west Sohag, Egypt. MODFLOW and MODPATH 10.2.3 were used under the platform of Groundwater Modeling System (GMS) to construct a hydraulic groundwater flow model to simulate the flow of the riverbank filtration system. Six pumping rates with two scenarios were conducted to investigate the system's hydraulic performance. Water samples were collected from the Nile River, abstraction wells, and groundwater to characterize the water quality. The results indicated that the application of riverbank filtration is promising due to the significant hydraulic connection between the Nile and the aquifer. However, the system hydraulic aspects should be taken into consideration during the design phase as they may affect the RBF hydraulic performance and its efficiency. It became apparent how effective RBF is at eliminating pathogens and suspended solids. Infiltrated water, on the other hand, has higher iron and manganese amounts than the Nile water. HIGHLIGHTS New scope in water treatment process in Egypt.; More sustainable and cost effective for water supply.; Green technology.;

A fully non-targeted analytical workflow for the investigation of a riverbank filtration site located at the river Danube has been developed and applied. Variations of compound intensities at different sampling locations of the riverbank filtration site and, for a single production well, over a monitoring period of one year have been investigated using liquid chromatography combined with time-of-flight-mass spectrometry followed by evaluation via non-targeted data analysis. Internal standardization and appropriate quality control strategies have been implemented into the workflow for reduction of possible methodological biases influencing data interpretation. Emphasis was placed on the assessment of different blank elimination steps and the final blank elimination strategy is reported. The spatial study of the selected riverbank filtration site revealed a homogenous composition of the filtered water sampled at 11 different locations across the 32,000 m2 site, except for one sampling location in a zone of the aquifer, which was only weakly connected to the well field in terms of hydrogeological conditions. The examination of time-dependent changes of the composition of surface and groundwater obtained at the riverbank filtration system revealed that the non-targeted workflow is fit-for-purpose regarding the assessment the stability of filtration efficiency and compound residence time in the riverbank filtration compartment. In total, 677 compounds were selected for the investigation of the time-dependent variations of the filtration process. Analysis of the signal intensities of these compounds revealed that the riverbank filtration is significantly reducing the intensity and number of compounds present in surface water over a wide polarity range. In addition, the method enabled the determination of compound residence times in the riverbank filtration system ranging from 5 to 7 days. [ABSTRACT FROM AUTHOR]

Despite being a simple and inexpensive pretreatment technology, the cost-effectiveness of riverbank filtration (RBF) depends on complex hydrogeological and hydrogeochemical variables. One of the most important issues for decision makers regarding RBF is optimal site selection. Therefore, a methodology for multicriteria site evaluation for large-scale RBF schemes is offered. The methodology is primarily designed as a prescreening method, applied over a wide area, but can also serve as a guide for evaluating individual RBF sites. To facilitate further discussion about improvements on the methodology, the reasoning behind each relevant factor and its weight in the evaluation is presented. The methodology is divided into three sequential steps through which a site can be assessed. The first step is to establish the existence of connectivity between the river and aquifer. This is termed the essential criterion, and is a binary determination of site suitability. If the site is determined to be suitable, it is then assessed via a set of quantity criteria, which measure the aquifer capacity and amount of bank filtrate that can be effectively abstracted. Lastly, water quality criteria are assessed by means of surface-water and groundwater quality. The quantity and quality criteria form a result expressed as the site suitability index (SSI), which ranges from 0 to 1, where higher scores represent increased suitability. Finally, the methodology is applied to evaluate existing sites of large-scale RBF application as a demonstration of its applicability. The success of these existing sites is compared to the calculated SSI value and discussed. [ABSTRACT FROM AUTHOR]

The main challenge of water resource management in high-stress regions, especially in developing countries, is in adopting non-traditional methods to obtain safe drinking water in desired quantities. In Egypt, the riverbank filtration (RBF) system is one of the most common solutions to solve rivers’ water quality issues. Several sites have been investigated, and the system has demonstrated tremendous potential. The drinking water plant in Embaba, Giza, Egypt, is considered in this study to improve the quality of the abstracted water through the vertical well system. The numerical code of MODFLOW and MT3D is used to simulate the impact of using the emplacement of the gravel-pack filter (GPF). Three different scenarios were investigated: the first consists of vertical GPF; the second is horizontal GPF for different geometries, depths, widths or thicknesses, lengths, and permeability of the filter material; and, the third is drilling a pipe filter through the riverbed for different pipe numbers, depths, and the material’s hydraulic conductivity. The results revealed that the riverbank filtration sharing (RBFS) rate was increased by increasing the filter width or thickness at the riverside, the filter pipe numbers, the length of the horizontal filter, and the permeability of filter material. At the same time, the thickness of the river bed decreased by increasing the filter width at the groundwater side. Also, the RBFS was increased by increasing the filter width or the thickness in the two directions and the pipe length. However, it returned to decrease again due to groundwater sharing. Thus, the RBF design should carefully consider the gravel-pack, pipe filter geometry, and permeability impact rate of RBFS.

Due to extensive water exchanges and abundant active biochemical compositions, active and complex hydrogeochemical processes often exist in riverbank filtration (RBF). The distribution of microbes is considered to be profoundly affected by these processes and is considered to impact the hydrogeochemical processes and the migration and transformation of water pollutants in turn and then impact the water quality. The distribution of microbes and their response to the physiochemical properties along a vertical RBF profile perpendicular to the Songhua River in Northeast China was explored by using 16 S rRNA and redundancy analysis (RDA). The results showed that various microbes were found in the vertical riparian filter (RBF) curve, including Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, and Firmicutes. With increasing depth (vertical) and distance from the river (lateral), the microbial community and diversity in the RBF sediment profile decreased. Nitrospirota, Pseudomonas, Gammaproteobacteria, Ochrobactrum, Acinetobacter and Desulfobacterota of the RBF core taxa were also significantly correlated with the biotransformation behavior of typical groundwater pollutants (ammonia, Fe, Mn and S). The amount of As in the RBF is too low to sustain microbial survival. Some microbes in RBF can also degrade natural organic pollutants. This study not only revealed the spatial distribution of geological microbes under the impact of hydrological processes but also lays a foundation for the further study of the hydrobiogeochemical processes of active biochemical compositions in groundwater and water quality evolution, which is of positive significance to ensure the quality safety of the drinking water supplied by RBFs.

One of Hungary's strategic water sectors is the supply of drinking water, which relies heavily on socalled riverbank filtration systems. About 35-40% of the national drinking water supply comes from riverbank filtered aquifers. Today in Hungary, 40% of the population; nearly four million people's daily water needs are met from riverbank filtered aquifers. In the future, 75% of our drinking water sources will be bank-filtered, which means that they will also be of great importance for future water resource management. The main water abstraction device in these aquifers is the well, or a special type of well, the horizontal collector well (HCW). In our work, we will focus on the hydraulic investigation of these types of wells. Using modern modeling software, the impact of the special design of HCWs on groundwater flow conditions can be well modeled. In our work, the yield distribution between the arms and the impact on the potential relationships are discussed in more detail and the results of this modeling are presented. [ABSTRACT FROM AUTHOR]

Although riverbank filtration (RBF) has been widely applied in China, the managers do not pay enough attention to the inevitable clogging issues during continuous RBF operation. The RBF site, which is located near the Lalin River, northeastern China, was selected as the study area, and the laboratory column experiments were used to simulate the RBF process and further investigate the physical and chemical clogging. The removal of turbidity (59.4–95.1%), COD (21.9–71.7%), NH4+ (10.9–39.4%), Fe (18.5–64.8%), and Mn (19.8–71.7%) demonstrated the water quality improvement by RBF. Whereas, the significant decrease in permeability (39.6–88.2%) also indicated that the clogging issues could not be ignored during RBF. Among them, the physical clogging-dominated area, chemical clogging-dominated area, and the transition zone were located at 0–12.5%, 37.5–100%, and 12.5–37.5% of the infiltration pathway, respectively. Moreover, the concentration of suspended particle materials, mean size of riverbed sediments, and aquifer media are the major impact factors for physical clogging; the precipitation of soluble constituents and redox reaction and other hydrochemical processes were the major impact factors for chemical clogging. The conclusion of this study can contribute to managers alleviating the clogging issues and improving the effectiveness of the sustainable operation in the local RBF system. [ABSTRACT FROM AUTHOR]

From 2014 to 2020, a full-scale horizontal well was operated to investigate the performance of full-scale riverbank filtration (RBF) in the Nakdong River in Korea, which is significantly impacted by the effluents from sewage treatment plants. In this study, an individual lateral full-scale horizontal collector well was investigated for the first time in Korea, and its performance was determined based on the turbidity and levels of iron, total nitrogen, dissolved organic matter, and four selected trace organic contaminants (TrOCs) (tebuconazole, hexaconazole, iprobenfos, and isoprothiolane) in the RBF and Nakdong River. The turbidity of the river was high with an average of 10.8 NTU, while that of the riverbank filtrate was 0.5 NTU or less on average. The average dissolved organic carbon (DOC) concentrations were 2.5 mg/L in the river water and 1.4 mg/L in the riverbank filtrate, which indicated a 44% reduction in DOC content during the RBF. Out of the 10 laterals, 8 laterals exhibited similar levels of iron, manganese, total nitrogen, DOC, and total hardness, electrical conductivity, and turbidity. The characteristics of the remaining two laterals were different. Because the groundwater inflow was relatively low (<10%), the laterals were contaminated by agricultural land use before the installation of the RBF. This is the first study to report changes in water quality according to individual laterals in a river affected by wastewater effluents. The filtration unit exhibited more than 90% removal rates for tebuconazole and hexaconazole. However, the removal rate for iprobenfos was approximately 77%, while that for isoprothiolane was 46%. The four selected TrOCs in this study were not detected in the groundwater. We found that some organic micropollutants were effectively removed by the RBF. [ABSTRACT FROM AUTHOR]

In the present work measurements of chloride concentrations were used to assess the variability of infiltration conditions and contributions of surface water and local groundwater to the discharge of wells at Krajkowo riverbank filtration site (western Poland). Tests were performed on samples from 26 wells located in a well gallery close to the River Warta. Due to higher chloride concentrations in river water in comparison with local groundwater, significant differences in concentrations in samples from individual wells were noted. In particular, lower chloride concentrations in 11 wells were recorded, which can be linked to the local occurrence of low-permeability deposits in the superficial zone; a locally higher degree of riverbed sediment clogging in the highly convex meandering zone, where strong erosion of the riverbed occurred, which in turn led to increased clogging; the occurrence of a more intensive groundwater inflow into the river valley due to water infiltration from a smaller river entering the River Warta valley, as well as unfavourable conditions for the infiltration of surface water to the lower part of the aquifer with a greater thickness. Differences in chloride concentrations observed were also used to quantify approximately river water contribution to the well production. The average contribution of the River Warta to the recharge of the entire well gallery was estimated at 59.8%.

Study region: A riparian zone within the Songhua River Basin in Northeast China, characterized by a continental monsoon semi-humid climate. Study focus: River infiltration is an important part of groundwater recharge at riverbank filtration (RBF) sites and largely depends on the riverbed hydraulic conductivity (RHC). The influence of river scouring and deposition on RHC is not completely clear, resulting in calculation inaccuracies in the rate of river water infiltration to the aquifer. Thus, the study determined the relationship between RHC and sediment particle size using stepwise regression analysis and a genetic algorithm. A hydrodynamic and sediment transport model (Delft3D) was used to simulate the spatial distribution of sediment particle sizes. A numerical groundwater flow model was also established, using Visual MODFLOW, in which the river boundary was generalized into a third type of boundary condition, and RHC zoning was performed to improve the accuracy of the simulation. New hydrological insights: The findings showed that accurate prediction of RHC is essential for the assessment of groundwater resources in riparian zones. This is crucial for RBF managers, as they will be able to adjust the pumping rate according to the hydrological conditions of the river to either access more water resources in wet years or avoid a series of ecological and geological problems caused by excessive groundwater exploitation in dry years.

Riverbank filtration (RBF) is one of the most productive and low-cost technologies for obtaining purified water throughout the year. The inevitable problem associated with RBF is clogging, a complex phenomenon that obstructs the flow. The present study conducted laboratory experiments on two different filter materials (uniformly graded) collected from the Ganges River bed from an RBF site in Haridwar. The primary focus is to study the factors influencing the clogging mechanism that affects the hydraulic conductivity, K of the filter material. The variation in the piezometric head, porosity, specific infiltration resistance, and the progressive clogging of the filter material is studied considering the experimental results. It is observed that the retention and intrusion of suspended particles depend on the grain size of filter material and fine sediments. The clogging of pores is more at the initial depths (2–7.5 cm), demonstrating the phenomenon of physical clogging. For every experimental run performed, as time progressed, with increased resistance and head difference, K and porosity of the filter materials decreased (Filter material-1, 47.17% and 48%; Filter material-2, 93.43% and 81%). With an increase in initial discharge, q0, K is partially recovered, presenting the initial desiltation process. Further, as time elapsed and with an increase in the turbidity, C, from 500 to 1,000 ppm, the clogging advanced resulting in decreased K of the filter materials. Therefore, taken as a whole, the ratio of mean size of filter material to suspended particles, q0, C, and time are considered as the dominant factors influencing the clogging process. Mathematical regression models for both the filter materials are formulated and found to estimate K reliably. The correlation coefficients calculated for both the models at a 95% confidence level are 0.814 and 0.965, respectively, and are statistically significant, presenting the functional dependency of K on the ascertained parameters as acceptable. [ABSTRACT FROM AUTHOR]

Essential hydrogeological parameters related to riverbank filtration, such as grain size (D50) of aquifer soils, hydraulic gradient, bed height, fine content, as well as operation and detention period, were explored in laboratory column studies to determine critical percentage total coliform removal. Increases in total coliform removal efficiency were seen for both in situ aquifer soil and altered aquifer soils as detention and operating period increased. With an increase in detention and operation period from 1 to 72 h, the percentage total coliform removal for aquifer soil increased from 42.5% to 94.3% and 10.4% to 77.11%, respectively. The removal of total coliform increased from 94.3% to 99.9% as the percentage fine content increased from 2.5% to 15%, increased from 94.3% to 98% as the hydraulic gradient decreased from 1.45 to 1.1. An increase was noticed from 73.1% to 95.9% as the mean grain size decreased from 3.2 to 0.22 mm. The importance of hydrogeological parameters impacting coliform removal was demonstrated using multiple linear regression analysis. Detention period and percentage of fine content were directly proportional to total coliform removal effectiveness among various hydrogeological parameters, but percentage total coliform removal was inversely proportional to hydraulic gradient as well as to mean grain size. The model was validated using field study data from the riverbank filtration located on the Rushikulya River, which yielded excellent results, ensuring the accuracy of the model produced. The Badamadhapur riverbank filtration facility was also shown to be effective in removing total coliform pathogens. [ABSTRACT FROM AUTHOR]

An experimental field study was performed to investigate riverbed clogging processes and associated monitoring approaches near a dam-controlled riverbank filtration facility in Northern California. Motivated by previous studies at the site that indicated riverbed clogging plays an important role in the performance of the riverbank filtration system, we investigated the spatiotemporal variability and nature of the clogging. In particular, we investigated whether the clogging was due to abiotic or biotic mechanisms. A secondary aspect of the study was the testing of different methods to monitor riverbed clogging and related processes, such as seepage. Monitoring was conducted using both point-based approaches and spatially extensive geophysical approaches, including: grain-size analysis, temperature sensing, electrical resistivity tomography, seepage meters, microbial analysis, and cryocoring, along two transects. The point monitoring measurements suggested a substantial increase in riverbed biomass (2 orders of magnitude) after the dam was raised compared to the small increase (~2%) in fine-grained sediment. These changes were concomitant with decreased seepage. The decreased seepage eventually led to the development of an unsaturated zone beneath the riverbed, which further decreased infiltration capacity. Comparison of our time-lapse grain-size and biomass datasets suggested that biotic processes played a greater role in clogging than did abiotic processes. Cryocoring and autonomous temperature loggers were most useful for locally monitoring clogging agents, while electrical resistivity data were useful for interpreting the spatial extent of a pumping-induced unsaturated zone that developed beneath the riverbed after riverbed clogging was initiated. The improved understanding of spatiotemporally variable riverbed clogging and monitoring approaches is expected to be useful for optimizing the riverbank filtration system operations.

An experimental field study was performed to investigate riverbed clogging processes and associated monitoring approaches near a dam-controlled riverbank filtration facility in Northern California. Motivated by previous studies at the site that indicated riverbed clogging plays an important role in the performance of the riverbank filtration system, we investigated the spatiotemporal variability and nature of the clogging. In particular, we investigated whether the clogging was due to abiotic or biotic mechanisms. A secondary aspect of the study was the testing of different methods to monitor riverbed clogging and related processes, such as seepage. Monitoring was conducted using both point-based approaches and spatially extensive geophysical approaches, including: grain-size analysis, temperature sensing, electrical resistivity tomography, seepage meters, microbial analysis, and cryocoring, along two transects. The point monitoring measurements suggested a substantial increase in riverbed biomass (2 orders of magnitude) after the dam was raised compared to the small increase (~2%) in fine-grained sediment. These changes were concomitant with decreased seepage. The decreased seepage eventually led to the development of an unsaturated zone beneath the riverbed, which further decreased infiltration capacity. Comparison of our time-lapse grain-size and biomass datasets suggested that biotic processes played a greater role in clogging than did abiotic processes. Cryocoring and autonomous temperature loggers were most useful for locally monitoring clogging agents, while electrical resistivity data were useful for interpreting the spatial extent of a pumping-induced unsaturated zone that developed beneath the riverbed after riverbed clogging was initiated. The improved understanding of spatiotemporally variable riverbed clogging and monitoring approaches is expected to be useful for optimizing the riverbank filtration system operations.

Study region: This study focuses on the simulation of flow and transport of potential contaminants at the riverbank filtration (RBF) site at Embaba, Cairo. RBF has a high potential along the Nile in Egypt as a pre-treatment step for drinking water production. As the site in Cairo can be affected by low water quality and spills of contaminants, the aim was to assess the RBF efficiency under various hydrological, geohydraulic and operational conditions. Study focus: MODFLOW, MT3D and MODPATH were used in this study. Three cases were considered to identify the share of bank filtrate in pumped water and the travel time. The first case focused on the river hydrograph and the permeability of the riverbed; the second on clay cap thickness, aquifer and riverbed hydraulic conductivities, and groundwater abstraction downside of the RBF scheme; and the third on different RBF well abstraction rates, depths, screen lengths and distances from the river bank. New hydrological insights for the region: The results indicate that favorable conditions for RBF sites. Good conditions for RBF include high river stage and riverbed permeability, high aquifer hydraulic conductivity and abstraction rates resulting in high portions of bank filtrate. Design and operation analysis indicate that the abstraction wells should be shallow and located close to the river bank to achieve shorter travel times, thus increasing productivity and preventing high manganese concentrations in the pumped bank filtrate. Due to the natural flow gradient from the Nile towards the RBF wells, changing conditions have impact on the portions of bank filtrate, making the site special.

Study region: Poland, Warta River catchment. Study focus: The study aimed to explain the reasons for spatial variability in chloride concentrations at the Mosina-Krajkowo riverbank filtration (RBF) site located along the river. This variability is attributed to RBF’s different intensity along the river sections, related, among others, to clogging development. The RBF effectiveness was studied using groundwater flow modelling by: examining the water balance in zones established on hydrogeological setting and chloride concentrations; travel time of the bankfiltrate investigation; RBF parametrisation (i.e. infiltration per unit area and specific infiltration per unit of riverbank). New Hydrological Insights for the Region: The study identifies zones of the most favourable RBF conditions and establishes the variability causes. The overall share bankfiltrate was found at 75.8 %. Its spatial variation ranged widely from 41.1–89.3%, confirming the usefulness of the RBF performance sectional analysis in managing this type of site. The highest proportion of surface water (>80 %) occurred along the straight river section, where the riverbed was built by fine and medium sands (preventing penetration of organic suspension into the aquifer). In contrast, the lowest values (

Overhanging riverbank stability is a key feature of bank retreat. Although different mechanisms of bank collapse have been studied by many researchers, prediction of cantilever failure patterns and understanding of three‐dimensional failure surfaces continue to puzzle scientists. To address this problem, we conducted laboratory experiments and numerical simulations to investigate the stability of overhanging riverbank. In the laboratory experiments, we analyzed the characteristics of failure surface using a three‐dimensional laser scanner. Results show that with decreased ratio between bank height and near‐bank water depth, there is a transition from a 'tensile failures followed by toppling failure' pattern to a 'shear failure' pattern. Flow infiltration in our experiments leads to a sharp decrease in soil shear strength and consequently the occurrence of shear failure. For toppling failure, the observed upper retreat distance is much greater than the lower undermining depth, thus challenging the widely adopted assumption of a constant failure surface along the endpoint of the cantilever. Also, we found that failure surface distance can be characterized by twice the width of the overhanging block. As for the failure surface angle, a negative linear correlation is proposed with respect to bank retreat distance, implying a distinct distribution of bank stability along the arched‐shape bank line induced by bank collapse events. Overall, our study deepens understanding of overhanging stability, providing a new perspective on bank retreat process, critical for the morphodynamics of rivers and estuaries. Plain Language Summary: Overhanging bank stability is a key process of river morphological dynamics, which plays an effective role in bank retreat and soil loss in multi‐layered riverbanks. Therefore, it significantly affects river engineering and management. Because of the difficulty in obtaining measurements, predicting large‐scale bank collapse and reducing economic losses are still hard to tackle. To this end, we conducted laboratory and numerical studies to better understand the mechanism of cantilever failure. Both laboratory and numerical results indicate that an increase in bank height or decrease in water depth causes the shift of bank failure mechanism from shear to toppling failure. By using a three‐dimensional laser scanner, we analyzed the characteristics of failure surface which imply a distinct distribution of bank stability along the collapse‐induced arched‐shape bank line. Overall, this study provides a new perspective for the understanding of overhanging stability, which should be considered for better prediction and guiding realistic protection. Key Points: Shear‐ or toppling‐type cantilever failure is related to the ratio between bank height and near‐bank water depthThe distance of the toppling failure surface to the bank line is around twice the width of the overhanging block3D structures of failure surfaces indicate a negative linear correlation between failure surface angle and bank retreat distance [ABSTRACT FROM AUTHOR]

Changes in the water quality by the riverbank filtration (RBF) process were investigated in the field-scale demonstration sites. The overall water quality was improved by RBF, but Fe2+ concentration significantly increased in the riverbank-filtered water more than in the river water. This result would be caused by the interaction between the iron minerals and the river water in the aquifer and the influx of the hinterland groundwater into RBF wells. Dissolution properties of iron from the aquifer soils cored at the sites were evaluated through incubation experiment considering various values of redox potential (Eh), dissolved oxygen (DO), and hydrogen-ion concentration exponent (pH). These results presented that at the incubator with the final Eh of 470 mV, DO of 3.4, and pH of 4.53, the iron from the aquifer soil was most dissolved, and the pyrite and siderite contents in the aquifer soil decreased significantly from 11.5 to 6.22% and from 50.8 to 24.5%, respectively. Based on changes of ion concentrations (such as Fe2+, Fe3+, SO42− and NO3−) and iron species in the incubators, it was believed that pyrite and siderite minerals in the aquifer soils cause an increase in the Fe2+ concentration with the absence of DO and an increase in the Fe2+ and Fe3+ concentrations with the presence of DO. The dissolution rates of iron minerals into Fe2+ and Fe3+ were dependent on Eh, pH, and DO and were more sensitive to Eh and pH than DO. The results of this study can provide information on RBF site selection and its operation. [ABSTRACT FROM AUTHOR]

Various hydrogeochemical processes can modify the quality of river water during riverbank filtration (RBF). Identifying the subsurface processes responsible for the bank-filtered water quality is challenging, but essential for predicting water quality changes and determining the necessity of post-treatment. However, no systematic approach for this has been proposed yet. In this study, the subsurface hydrogeochemical processes that caused the high concentrations of total iron (Fe) and sulfate (SO42−) in the bank-filtered water were investigated at a pilot-scale RBF site in South Korea. For this purpose, water quality variations were monitored in both the extraction well and the adjacent river over five months. The volumetric mixing ratio between the river water and the native groundwater in the RBF well was calculated to understand the effect of mixing on the quality of water from the well and to assess the potential contribution of subsurface reactions to water quality changes. To identify the subsurface processes responsible for the evolution of Fe and SO42− during RBF, an inverse modeling based on the chemical mass balance was conducted using the water quality data and the calculated volumetric mixing ratio. The modeling results suggest that pyrite oxidation by abundant O2 present in an unsaturated zone could be a primary process explaining the evolution of total Fe and SO42− during RBF at the study site. The presence of pyrite in the aquifer was indirectly supported by iron sulfate hydroxide (Fe(SO4)(OH)) detected in oxidized aquifer sediments. [ABSTRACT FROM AUTHOR]

Groundwater exploitation in a riparian zone causes water infiltration from the river into the aquifer. Owing to adsorption and redox reactions along the flow path, the quality of water flowing from the river to groundwater wells is variably altered. The riverbed composition often involves spatiotemporal differences due to frequent changes in hydrological conditions. These changes create uncertainties in the transport and removal of solutes in the river water. In this study, the hydrodynamic field associated with riparian groundwater, changes in the structure of riverbed sediments caused by erosion and deposition, fluctuations in surface water and groundwater levels, and the removal efficiency of pollutants from groundwater through pumping were investigated. This involved in situ monitoring and sample testing of the composition of the river water, riverbed sediments, riverbed pore water, and groundwater during dry and wet seasons. Implementation of field in situ column experiments and molecular biology evidences were conducive to identifying the main biogeochemical processes occurring in the riverbed. The findings indicated that riparian groundwater exploitation alters the natural groundwater flow field, while fine sand deposition and microbial adsorption can reduce river recharge to aquifers by diminishing riverbed hydraulic conductivity. Shallow sediments within 1 m depth mainly involve NO 3 − reduction and E. coli adsorption. Reductive dissolution of Mn dominates in the deeper sediments. Additionally, reductive dissolution of Fe and dissimilatory nitrate reduction to ammonium (DNRA) drive high Fe2+ and NH 4 + concentrations in groundwater. The findings can improve the management of riparian groundwater and aid in the optimization of a plan for its exploitation. [Display omitted] • More than 90% of nitrates and E.coli are removed within 1m of the riverbed. • Reduction dissolution of minerals increases iron and manganese levels in groundwater. • Nitrate reduction drives high concentrations of NH 4 + in riparian groundwater. • Iron, manganese and ammonium are potential risks for riverbank filtration systems. [ABSTRACT FROM AUTHOR]

Health issues related to aquifer contamination with perchlorate are a growing concern in drinking water management. This study describes perchlorate transport and degradation processes from a contaminated stream toward drinking water pumping wells. Investigations are based on laboratory experiments and field measurements conducted at a well field near Bordeaux (France) in a heterogeneous carbonate aquifer interacting with a stream. Field measurements facilitated the characterization of perchlorate contamination and stream-to-aquifer flow. Experiments on columns of streambed sediments conducted in the laboratory confirmed that perchlorate had been degraded in the hyporheic zone. A one-dimensional reactive transport model was implemented to estimate Monod kinetic rates, which account for the inhibition of perchlorate degradation by nitrate. The estimated half-saturation constant for perchlorate (k 1 / 2 Pcl ) is 6.93 10−9 mol L−1 and the estimated maximum specific degradation rate ( k max Pcl ) ranges between 10−5 and 4.0 10−3 mol L−1 day−1. Despite degradation in the hyporheic zone, perchlorate-contaminated stream water reaches drinking-water-production units. Such contamination highlights the effects of preferential flow paths between the stream and the pumping wells and significant hydraulic gradients caused by drawdowns. In such contexts, in spite of a good potential for degradation, riverbank filtration may not be effective for the protection of drinking water wells. Lessons from this study also reveal that contamination monitoring can be misleading: low concentrations can be reported in monitoring wells between the contaminant source and the production wells, but the latter may yet be contaminated. [ABSTRACT FROM AUTHOR]

Harmful algal blooms represent a major environmental problem that is rapidly growing all over the world. In the present work, the effectiveness of simulated bank filtration (BF), as an economical water treatment option, to remove cyanotoxins under different levels of nutrients (nitrates and phosphates) was investigated. Vertical flow‐through columns pre‐acclimated with two levels of nutrients (e.g., nitrate and phosphate—10 vs. 50 mg/L) were exposed to two different levels of cyanotoxins (10 vs. 75 µg/L). Results from our study confirmed the ability of simulated BF to remove cyanotoxins. High cyanotoxins removals (>70%) were achieved regardless of the levels of nutrients and cyanotoxins. It can be recommended to guarantee enough travel time (>7 d) to enhance the removal of cyanotoxins. Among the removal mechanisms, biodegradation was the predominant removal mechanism. [ABSTRACT FROM AUTHOR]