Drinking Water Pipelines Research Articles

An interpretable machine learning-based pitting corrosion depth prediction model for steel drinking water pipelines

Steel pipes are a crucial element of the water supply system and are necessary for safely delivering large quantities of water from purification plants to consumers. Corrosion is a significant factor that deteriorates the interior and exterior of the steel pipes. Although the effectiveness of machine learning has been demonstrated in various fields, machine learning has rarely been used to identify corrosion mechanisms in buried steel pipes. A hybrid machine-learning–based corrosion depth prediction model was developed by integrating a corrosion depth trend prediction model based only on elapsed years with machine-learning algorithms. Shapley additive explanation (SHAP) was used to analyze the hybrid machine-learning–based corrosion depth prediction models, revealing corrosion mechanisms and explaining the interactions among influencing factors through global and local interpretations. The SHAP local interpretation showed that the hybrid machine-learning–based corrosion depth prediction models can effectively capture the interrelationship between soil and water corrosiveness.

Unveiling the transformation of 2,4,6-trihalophenols by active species in drinking water pipelines: The role of goethite

The long-term accumulated pipe scale in the water distribution system (WDS) is vital for ensuring the safety of drinking water delivery. This study revealed a novel positive role of pipe scale in triggering interface free radicals for aromatic substances degradation. The goethite (main constituents of pipe scale) converts from the trivalent state to the divalent state by withdraw electrons from aromatic phenolic compounds. Active free radicals such as hydroxyl radical (OH), Cl, and ClO were subsequently formed via a cascade of chain reactions under WDS conditions, among which OH was the dominate active species driving efficient transformation of 2,4,6-trichlorophenol (60.8%) and 2,4,6-tribromophenol (80.5%) and the corresponding toxicity attenuation. The goethite mediated chlorination is a surface reaction following Langmuir–Hinshelwood model. Our works revealed the presence of natural source of OH for disinfection byproducts transformation. Given the ubiquitous existence of iron scales inside ductile iron pipe, the finding renewed the understanding of the impact of WDS on drinking water quality.

Seismic vulnerability assessment of buried water supply and sanitation pipelines using the analytic hierarchy process: a methodology and application

The evaluation of seismic vulnerability in buried pipelines within water supply and sanitation networks stands as a critical endeavor in safeguarding infrastructure against the impacts of earthquakes. In response, this study introduces a systematic methodology rooted in the Vulnerability Index (VI), leveraging the Analytic Hierarchy Process (AHP) to allocate weights to factors influencing pipeline seismic behavior. Through the derivation of an expression for calculating the VI based on these weighted factors, our objective is to furnish a comprehensive pipeline classification system, thereby providing a strategic overview of the networks' seismic resilience. This method's practical utility will be exemplified through the examination of concrete cases involving drinking water pipelines (DWP). Furthermore, the scope will extend to encompass sanitation pipelines, thereby validating the methodology's effectiveness across both domains. By systematically assessing the seismic vulnerability of these crucial infrastructures, we aim to fortify their resilience against seismic events, ensuring the continued provision of essential services even in the face of natural disasters. This study's significance lies not only in its contribution to the field of infrastructure resilience but also in its practical implications for urban planning and disaster management. By elucidating the factors influencing pipeline vulnerability and providing a robust framework for assessment, decision-makers can better prioritize resource allocation and mitigation efforts, ultimately enhancing community safety and well-being. Furthermore, the methodology's adaptability and scalability render it applicable to diverse contexts, facilitating its integration into broader risk management strategies. As such, this study serves as a valuable tool for policymakers, engineers, and stakeholders seeking to enhance the resilience of water supply and sanitation networks in earthquake-prone regions. Through informed decision-making and proactive measures, we can build more resilient communities capable of withstanding the challenges posed by seismic hazards.

Application of a soil temperature model for simulating the effect of dis-trict heating pipes on drinking water pipelines

According to Dutch legislation the drinking water temperature is required to be below 25°C at the tap to meet legionella prevention [1]. This requirement possibly limits the storage of heat in the subsoil and the transport of heat through pipelines. In order to asses the impact of heat transport pipelines on the drinking water temperature in adjacent drinking water pipelines, a soil temperature model was developed. This coupled micro-climate [2] and heat transport model relates atmospheric conditions to the temperature distribution in the sub-surface [3]. The subsurface part of the model is based on a finite element discretization of the transient heat conduction equation in a single phase material. The coupling of the subsurface part of the model with atmospherical part of the model requires that the sensible heat flux, the latent heat flux, net radiation and the subsurface heat flux are in equilibrium at the land surface. Simulation periods of a number of years are discritized in time steps of one hour. The model is validated by comparing the model results with a large number of field measurements in the Dutch city Rotterdam-Kralingen [3].
 The validated model is used to predict the drinking water temperature in transport, primary and secondary pipeline networks. The transport networks supply heat and water to the primary networks. Primary networks distribute their heat and water to secondary networks that transport it to buildings.
 with and without heating pipelines parallel to drinking water pipelines, with a limited flow of drinking water. The inner diameter of the heat supply and return pipelines, which are usually located close to each other, is 160.3 mm. The heat supply temperature is 90°C and the return temperature is 70°C. The inner diameter of the drinking water pipelines is 152 mm. The heat transport pipelines consist of an inner steel pipe with a wall thickness of 4 mm, a PUR isolation of 56 mm and a PE sleeve of 4 mm. The finite element discretization captures the geometry of the insulated pipeline and associated effective thermal properties. Drinking water pipelines have a PVC wall with a thickness of 4 mm. The drinking water pipeline cover depth is 1.00 m, the distance in between the drinking water pipeline and heat return pipeline is 0.75 m and the soil cover of the heat supply pipelines is 1.00 m. Tiles cover a dry sandy soil for which the specific heat capacity is 800 J/kgK, the thermal conductivity is 1.6 W/mK and the density of the soil is 1600 kg/m3. The figure shows a seasonal variation of the drinking water temperature of 13.8°C and an increase of the drinking water temperature due to the presence of the heat transport pipelines of 2.0°C, which is almost constant throughout the year. The maximum drinking water temperature is found in August and amounts to 23.8°C if the heat pipelines are absent and 25.8°C if they are present.
 Table 1 presents the results of a study with variation of the drinking water pipeline soil cover, the distance in between drinking water pipeline and heat return pipeline and the soil cover of the heat supply pipelines. Based on this table decisions can be made on the type of construction and the effect of the heat transport pipelines on adjacent drinking water pipelines.
 The table shows that the cover depth of the drinking water pipeline strongly influences the increase of the drinking water temperature due to atmospheric conditions. A decrease of the soil cover from 2.00 m to 0.75 m raises the maximal temperature by 4.2°C. The presence of the heat transport pipelines increases the temperature of the drinking water by 1.7°C for the case of a small cover depth and 2.1°C for a large cover depth. A decrease of the distance in between the drinking water pipeline and the heat return pipeline from 2.5 m to 0.25 m raises the maximal drinking water temperature by 2.6 °C. The calculation results show that the drinking water temperature is not sensitive to the proposed cover depth variation of the heat supply pipelines. The computational results for all networks considered, are collected in an expert tool that can be accessed via: https://www.tkiwatertechnologie.nl/projecten/opwarming-van-drinkwater/.

Analysis of Premature Failure of a PVC Water Pipe

A case study of the failure analysis of a PVC drinking water pipeline is presented. One week after installation in a construction zone of a building, a longitudinal cracking, and pressure drop occurred in an underground pipeline, and an investigation was carried out to determine the causes of the event. Based on the results of visual inspection, dimensional metrology, plastography, microhardness, fractography, FTIR analysis, and stress analysis, the failure mechanisms of the pipe were identified as creep and slow crack growth. The cause of the development of these failure mechanisms was the exposure of the pipe, to a mixture of paint thinner and polyurethane paint, which generated plasticization, with the corresponding deterioration of the mechanical properties. The source of the plasticizer could have been an accidental spill or an incorrect final disposition of this chemical residue during the construction process of the building.

Comparison of modern and 40-year-old drinking water pipeline in northern Sinai region, Egypt: Characteristics and health risk assessment

BackgroundDrinking water quality is crucial for human health and well-being. This study evaluated the impact of replacing old asbestos pipelines with modern Polyvinyl Chloride (PVC) ones on drinking water quality in the North Sinai governorate of Egypt. Ninety-two water samples were collected from nine locations along the pipeline from Qantara water station to El-Arish city, and their microbiological and chemical characteristics were assessed. MethodsThis investigation was carried out during June and July 2019 to evaluate the drinking water in two distribution nets; old asbestos distribution pipes and new Polyvinyl Chloride water tubes (PVC). Microbiological analyses such as most probable number (MPN), total bacterial count (TBC), chemical assessments (water pH, electrical conductivity; EC, dissolved organic carbon; DOC), and health risk index (HRI) for multi-element concentrations were conducted. Standard analyses were followed to assess the water quality index (WQI) and Metal index (MI) and study the improvement percentage in the element's concentrations. ResultsThe highest values of TBC were in the city center district (219 CFUs mL−1), followed by Abu Saqual (184 CFUs mL−1), Resa (174 CFUs mL−1), and recently constructed pipes (80 CFUs mL−1). The pH (7.52 - 7.50) and EC (320 to 958 dSm−1) were within permissible limits. No bacterial indicators of fecal pollution were found in all drinking water samples. Results showed that the modern pipeline network significantly improved the concentrations of 23 elements, with the most significant improvements observed in cadmium (66.2%) and potassium (40.7%). HRI results for multi-element concentrations showed an impact on human health in Abu Saqual. WQI showed a decrease of 30% in toxic element concentration in the current pipelines, and MI assessment showed safe concentrations. ConclusionDrinking water's biological and chemical properties significantly improved, which matched global guideline standards. Our findings highlight the importance of regularly monitoring and updating drinking water infrastructure to ensure safe and high-quality drinking water.

The prevalence of extra- and intra- cellular antibiotic resistance genes and the relationship with bacterial community in different layers of biofilm in the simulated drinking water pipelines

Biofilms are one of the main habitats for microorganisms and promote the antibiotic resistance spread in the drinking water distribution system (DWDS). Nowadays, the research about antibiotic resistance genes (ARGs) in biofilms of DWDS focuses mainly on intracellular ARGs (iARGs) in the whole biofilm, lacking comprehensive knowledge of extracellular ARGs (eARGs), iARGs, and bacterial community in different biofilm layers. Moreover, the effect of residual chlorine on them is unclear. In this study, two identical biofilm reactors were set up to culture and collect biofilm. The eARGs/iARGs abundance and bacterial community composition were analyzed. We found that the eARGs relative abundance was generally higher than iARGs. The total relative abundance of eARGs in 95 % of biofilm samples was higher than that of iARGs. The PCoA results showed a sample-type difference in the iARGs abundance between the surface biofilm and the inner biofilm. Residual chlorine increased the total abundances of eARGs and iARGs. Furthermore, the bacterial community of the inner biofilm was more abundant than that of the surface biofilm in the chlorinated reactor. We also found that residual chlorine reduced the diversity of the surface biofilm. This study was beneficial for the risk assessment and dissemination control of ARGs.

Chlorine-resistant bacteria in drinking water: Generation, identification and inactivation using ozone-based technologies

Along with the expansion of cities and population growth, the demand for drinking water is increasing. Chlorine, the most common method of disinfection, is often used in the disinfection process of drinking water plants. Residual chlorine is routinely added to the water delivery network as an additive for continuous disinfection to ensure water safety from the drinking water pipelines to the customer's taps. However, some organisms can still survive even in conditions of high chlorine concentration. This also poses a significant risk to the safety of drinking water. This review investigates the origin of chlorine-resistant bacteria in drinking water networks, the species of chlorine-resistant bacteria found in recent years and the conventional methods of identification of chlorine-resistant bacteria, the current inactivation techniques for chlorine-resistant bacteria are also summarized. The research on inactivation of chlorine-resistant bacteria by ozone-based and other methods are especially highlighted.

Batteryless Sensor Devices for Underground Infrastructure—A Long-Term Experiment on Urban Water Pipes

Drinking water is becoming increasingly scarce as the world’s population grows and climate change continues. However, there is great potential to improve drinking water pipelines, as 30% of fresh water is lost between the supplier and consumer. While systematic process monitoring could play a crucial role in the early detection and repair of leaks, current practice requires manual inspection, which is both time-consuming and costly. This project envisages maintenance-free measurements at numerous locations within the underground infrastructure, a goal that is to be achieved through the use of a harvesting device mounted on the water pipe. This device extracts energy from the temperature difference between the water pipe and the soil using a TEG (thermoelectric generator), takes sensor measurements, processes the data and transmits it wirelessly via LoRaWAN. We built 16 harvesting devices, installed them in four locations and continuously evaluated their performance throughout the project. In this paper, we focus on two devices of a particular type. The data for a full year show that enough energy was available on 94% of the days, on average, to take measurements and transmit data. This study demonstrates that it is possible to power highly constrained sensing devices with energy harvesting in underground environments.

Impacts of hydrodynamic conditions and microscale surface roughness on the critical shear stress to develop and thickness of early-stage Pseudomonas putida biofilms.

Biofilms can increase pathogenic contamination of drinking water, cause biofilm-related diseases, alter the sediment erosion rate, and degrade contaminants in wastewater. Compared with mature biofilms, biofilms in the early-stage have been shown to be more susceptible to antimicrobials and easier to remove. Mechanistic understanding of physical factors controlling early-stage biofilm growth is critical to predict and control biofilm development, yet such understanding is currently incomplete. Here, we reveal the impacts of hydrodynamic conditions and microscale surface roughness on the development of early-stage Pseudomonas putida biofilm through a combination of microfluidic experiments, numerical simulations, and fluid mechanics theories. We demonstrate that early-stage biofilm growth is suppressed under high flow conditions and that the local velocity for early-stage P. putida biofilms (growth time < 14 h) to develop is about 50 μm/s, which is similar to P. putida's swimming speed. We further illustrate that microscale surface roughness promotes the growth of early-stage biofilms by increasing the area of the low-flow region. Furthermore, we show that the critical average shear stress, above which early-stage biofilms cease to form, is 0.9 Pa for rough surfaces, three times as large as the value for flat or smooth surfaces (0.3 Pa). The important control of flow conditions and microscale surface roughness on early-stage biofilm development, characterized in this study, will facilitate future predictions and managements of early-stage P. putida biofilm development on the surfaces of drinking water pipelines, bioreactors, and sediments in aquatic environments.

Early succession of biofilm bacterial communities in newly built drinking water pipelines via multi-area analysis

Biofilms inhabiting pipeline walls are critical to drinking water quality and safety. With massive pipeline replacement underway, however, biofilm formation process in newly built pipes and its effects on water quality are unclear. Moreover, differences and connections between biofilms in newly built and old pipes are unknown. In this study, early succession (≤ 120days) of biofilm bacterial communities (abundance and diversity) in upper, middle and bottom areas of a newly built cement-lined ductile iron pipeline were evaluated using improved Propella™ biofilm reactor and multi-area analysis. A comparison with old pipelines (grey cast iron, 10years) was performed. In the newly built pipeline, the abundance of biofilm bacteria did not change significantly between 40 and 80days, but increased significantly between 80 and 120days. The biofilm bacterial abundance (per unit area) in the bottom area was always higher than that in the upper and middle areas. Based on alpha diversity index and PCoA results, biofilm bacterial community richness, diversity and composition did not change significantly during the 120-day operation. Besides, biofilm shedding from the walls of newly built pipeline significantly increased bacterial abundance in the outlet water. Opportunistic pathogen-containing genera, such as Burkholderia, Acinetobacter and Legionella, were identified in both water and biofilm samples from newly built pipelines. The comparison between new and old pipelines suggested a higher bacterial abundance per unit area at the middle and bottom areas in old pipelines. Moreover, the bacterial community composition of biofilms in old pipelines was similar to that of newly built pipelines. These results contribute to accurate prediction and management of biofilm microbial communities in drinking water pipelines, ensuring the biosafety of drinking water. KEY POINTS: • Biofilm bacterial communities in different areas of pipe wall were revealed. • The abundance of biofilm bacteria increased significantly between 80 and 120days. • Biofilm bacterial community compositions of newly built and old pipes were similar.

EPIDEMIOLOGICAL INVESTIGATION OF ACUTE VIRAL HEPATITIS OUTBREAK: SUBSTANTIATION OF A SINGLE SOURCE

Objective: An outbreak of AVH was investigated with the objective of describing its epidemiological features. Material and Methods: This descriptive outbreak investigation of AVH was done from August to December 2022, in the catchment area of the southern region of Karachi. An active surveillance of the affected region was conducted. WHO’s standard case definition for AVH was used to identify cases. Suspected cases were tested for hepatitis A virus (HAV) and E virus (HEV) using immunochromatographic testing (ICT). Drinking water samples were tested for faecal contamination. Control measures were implemented to contain the outbreak. Descriptive analysis was done as per time, person, and place. Results: A total of 109 individuals were included in this study from 10th August 2021 to 31st October 2021. Out of these, 59 cases were confirmed serologically for Hepatitis A and E. Out of confirmed cases of AVH, 85.1% were positive for HEV, 12.8% for HAV, and 2.1% for both HAV and HEV. Males were affected more than females (P &lt; 0.05). One of the areas reported leakage in the drinking water pipeline and had the highest attack rate. Drinking water samples were found negative for contamination Conclusion: This study described the detailed methodology for the epidemiological investigation of an outbreak and described the epidemiological features of acute viral hepatitis and various measures taken to curb an outbreak. Key Words: Acute viral hepatitis, Hepatitis A, Hepatitis E, Outbreak investigation, Jaundice

Ultrasonic thickness measuring in-pipe robot for real-time non-destructive evaluation of polymeric spray linings in drinking water pipe infrastructure

Drinking water pipelines are mainly underground and exposed to corrosion. Polymeric spray liners are used as an economical renewal method to mitigate the consequences of internal corrosion of pipelines and prolong their useful service life by many water utilities around the globe. The quality assurance of such applications is currently limited to closed-circuit television (CCTV), which only provides visual information. As part of the Australian government-funded, thirty-four partner multi-million dollar project (CRC-P: Smart Linings for Pipes and Infrastructure project), this work focuses on measuring the post-application thickness of spray liners in pipes. In this article, we report the innovative development of in-pipe robotic sensing suite that leverages ultrasonic sensing to continuously inspect the thickness of the spray linings through non-destructive measurements. The ultrasonic sensor was calibrated by fabricating laboratory test sample made from polymeric spray linings. Continuous uninterrupted coupling was achieved through a custom designed mechanism which was proven to be reliable through field deployments. Extensive lab tests were conducted to validate the sensor measurements with the benchmark measurements producing results with sub-millimeter accuracy. Following lab validations, field trials in buried pipe assets of Sydney Water were conducted for pipe lengths over 35 m, and the field test results show the robotic system is capable of reliably providing accurate spray liner thickness along the pipeline in real-time through non-destructive evaluation.

Bacterial community structure and metabolic activity of drinking water pipelines in buildings: A new perspective on dual effects of hydrodynamic stagnation and algal organic matter invasion

Eutrophication and algal blooms have become global issues. The drinking water treatment process suffers from pollution by algal organic matter (AOM) through cell lysis during the algal blooms. Nevertheless, it remains unclear how AOM invasion affects water quality and microbial communities in drinking water, particularly in the stagnant settings. In this study, the addition of AOM caused the residual chlorine to rapidly degrade and below the limit of 0.05 mg/L, while the NO2−-N concentration ranged from 0.11 to 3.71 mg/L. Additionally, total bacterial counts increased and subsequently decreased. The results of Biolog demonstrated that the AOM significantly improved the utilization capacity of carbon sources and changed the preference for carbon sources. Full-length 16S rRNA gene sequencing and network modeling revealed a considerable reduction in the abundance of Proteobacteria, whereas that of Bacteroidetes increased significantly under the influence of AOM. Furthermore, the species abundance distributions of the Microcystis group and Scenedesmus group was most consistent with the Mandelbrot model. According to redundancy analysis and structural equation modeling, the bacterial community structure of the control group was most positively regulated by the free residual chlorine concentrations, whereas the Microcystis group and Scenedesmus group were positively correlated with the total organic carbon (TOC) concentration. Overall, these findings provide a scientific foundation for the evolution of drinking water quality under algae bloom pollution.

The Technological Alternatives for Energy and Hydraulic Improvements

The problem of converting attenuated hydraulic energy into power energy in an artificial local resistance unit placed on a gravity drinking water pipeline (outlet control valve, pressure regulator) without disrupting the hydraulic regime of the water pipeline is examined. It is recommended to replace the regulator with the same resistance hydraulic turbine, and thus, with its corrective device, automatically adjust the consumption outlet of the water pipe. The energy and economic data of the hydraulic turbine unit to be built on the «Arzakan-Yerevan» drinking water main pipelines have been presented as an example of proposal implementation. According to estimations, the small hydroelectric power plant on the Yerevan water pipeline could produce 90 million kWh of electricity per year. It should be noted that the water supply system in Yerevan has around 300 half-open valves and pressure control devices, and in case of conversion of many of them, it is possible to apply the suggestion given in the article.

Методические подходы к повышению надежности оценки факторов риска здоровью при использовании полимерных материалов в системе питьевого водоснабжения

Plastic pipes and coatings may contain additives, including metal stabilizers and antioxidants, designed to protect the material during manufacture and use. Some chemical compounds can be released from these plastic pipes and affect quality of drinking water. The article focuses on analyzing various approaches to examining polymer materials with the aim to assess migration of chemicals into drinking water. These approaches usually underlie methodologies of hygienic assessment developed for polymers. Migration was assessed under the same conditions as per two types of migration processes, a continuous and a sequential one. These two types of migration processes emulate conditions typical for different flows in drinking water pipelines: situations of continuous stagnation in the system and a standard flow when water is renewed regularly in water supply networks. More than 20 organic compounds were identified in tested water samples. Most of them occurred in small concentrations (excluding benzenesulfonic acid butyl amide). Moreover, many of these chemicals are not regulated in drinking water, there no standards or reference concentrations fixed for them or a relevant toxicological assessment. Given that, it is practically impossible to assess health risks caused by exposure to these chemicals according to conventional assessment procedures. It was also shown that release of chemicals differed considerably under different experimental designs. The results produced by successive migration tests indicated that intensity of migration from polymer materials the pipes were made from tended to change over time whereas the results of continuous migration tests showed that in case of stagnation quality of drinking water could deteriorate rather rapidly due to migration of organic compounds.

Methodical approaches to raising the reliability of health risk assessment when using polymer materials in drinking water supply

Plastic pipes and coatings may contain additives, including metal stabilizers and antioxidants, designed to protect the material during manufacture and use. Some chemical compounds can be released from these plastic pipes and affect quality of drinking water. The article focuses on analyzing various approaches to examining polymer materials with the aim to assess migration of chemicals into drinking water. These approaches usually underlie methodologies of hygienic assessment developed for polymers. Migration was assessed under the same conditions as per two types of migration processes, a continuous and a sequential one. These two types of migration processes emulate conditions typical for different flows in drinking water pipelines: situations of continuous stagnation in the system and a standard flow when water is renewed regularly in water supply networks. More than 20 organic compounds were identified in tested water samples. Most of them occurred in small concentrations (excluding benzenesulfonic acid butyl amide). Moreover, many of these chemicals are not regulated in drinking water, there no standards or reference concentrations fixed for them or a relevant toxicological assessment. Given that, it is practically impossible to assess health risks caused by exposure to these chemicals according to conventional assessment procedures. It was also shown that release of chemicals differed considerably under different experimental designs. The results produced by successive migration tests indicated that intensity of migration from polymer materials the pipes were made from tended to change over time whereas the results of continuous migration tests showed that in case of stagnation quality of drinking water could deteriorate rather rapidly due to migration of organic compounds.

Assessing the Hazards of Groundwater Logging in Tourism Aswan City, Egypt

This paper studies the groundwater logging problem in the Quaternary aquifer in Aswan city, Upper Egypt. Groundwater levels are already very high in Aswan city, but this has not been exploited, and it causes damage to the environment and infrastructure for roads, building, and templets. Rising groundwater leads to the deterioration and poor quality of agricultural lands. The main objective of this study is to assess and investigate the main reasons for the groundwater logging in the tourist city of Aswan using field investigation during different periods and gain a better understanding of the water dynamics in the study area. This study investigated the surface water levels in the High Dam Lake (HDL), the Kima Lake water levels, the recharge in the fish hatchery, the abstraction well rates in Kima and El-Shalal, and the leakage from the drinking water and wastewater network in Aswan city within the study area using field investigation. The results of this study show that the HDL is one of the most important sources feeding the aquifer in the study area, and it affects the rise and fall of the groundwater levels, but it is not the only factor that affects this problem. Moreover, the rise in the groundwater levels was due to the infiltration from the unlinking fish hatchery, the reduction in abstraction well rates from Kima Lake, the lack of abstraction from El shallal region, the increase in the leakage from drinking water pipelines, sewage networks and septic underground wastewater tanks; these factors are affecting groundwater logging in Aswan city. Potential groundwater level maps for the study area were generated using field data and ArcGIS technique for the years 2010, 2012, 2014, 2017, 2018, and 2020. Based on the results of the potential groundwater maps, the maximum and minimum difference for the groundwater levels in the study area between 2017 and 2012 reached 12.56 m and 0.83 m, respectively; also, between 2018 and 2017, the levels were 4.34 m and 0.25 m, respectively. Moreover, between 2020 and 2018, they were 8 m and 0.38 m, respectively.

Low-concentration iron promotes Klebsiella pneumoniae biofilm formation by suppressing succinic acid

BackgroundKlebsiella pneumoniae is widely distributed in water and plays a major role in both human and poultry infections. Many K. pneumoniae strains form biofilms on various surfaces, enhancing their pathogenicity and resistance to antibiotics. The water supply pipeline of chicken farms has become a hotbed for the growth of K pneumoniae biofilm because of its humid environment, and because the chicken drinking water pipeline is thin, it is easily blocked by the biofilm, and the diffused cells can cause repeated and persistent infections. Iron is vital to the growth of microorganisms and the formation of biofilms. Therefore, the aim of this study was to examine the effects of iron on K. pneumoniae biofilm formation and any associated metabolic changes to provide a rationale for reducing the formation of biofilms.ResultsBiofilm formation was enhanced to the greatest extent by the presence of 0.16 mM FeCl2, producing a denser structure under electron microscopy. The number of biofilm-forming and planktonic bacteria did not change, but protein and polysaccharide concentrations in the bacterial extracellular polymeric substances (EPS) were significantly increased by iron supplementation. To clarify this mechanism, intracellular metabolomic analysis was carried out, showing that the differential, down-regulated metabolites included succinic acid. The addition of 1.7 mM succinic acid counteracted the biofilm-forming effect of iron, with no bactericidal side effects.ConclusionThis study demonstrates the importance of succinic acid and iron in K. pneumoniae biofilms, and provides insight into the formation of K. pneumoniae biofilms and direction for the development of new antibacterial agents.

Utilization of in-pipe hydropower renewable energy technology and energy storage systems in mountainous distribution networks

Million miles of gravity-fed drinking water and sewage pipelines around the world, especially in rural and urban areas in mountain ranges, have introduced a new renewable energy sources (RES), i.e., in-pipe hydropower systems (IHS). Output power of this technology, similar to other types of RES, suffers from intermittency, while it is still more predictable in comparison to other technologies of RESs. Besides, energy storage systems (ESS) are introduced as a pivotal technology for dealing with the intermittent and non-dispatchable characteristics of IHS through spatio-temporal arbitrage. This paper aims to develop a stochastic mixed-integer linear programming (MILP) formulation that simultaneously determines the optimal location and size of ESS and IHS in a microgrid (MG) considering the correlation between prevailing uncertainties. In this regard, the proposed optimization problem minimizes the expected social cost of MG considering the AC power flow equations and operation constraints. Finally, the efficiency and applicability of the proposed model are illustrated using numerical simulations on the IEEE 33-bus distribution test system.