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Increasingly, collective actors in Europe, such as in the Netherlands and Italy, turn to litigation as the preferred strategy to attain their goals. Both at the national level and at the European level, civil society organisations (CSOs) are active in high‐profile cases, for example, in the field of asylum law. These CSOs operate in a different national political and legal system but do have similar European‐level opportunities. However, the extent to which European Union (EU) law is mobilised differs per CSO. This begs the following key question: Why do some CSOs mobilise EU law more frequently than others? Using empirical data, this article attempts to uncover what factors are relevant for four CSOs from Italy and the Netherlands whether to mobilise EU law or not. Most importantly, the article concludes that the framing of EU legal opportunities by the CSOs is considered to be relevant in (non‐)mobilisation of EU law. [ABSTRACT FROM AUTHOR]

The uniform flow in a horseshoe-shaped tunnel is often encountered in many practical cases. This pipe can be used for water drainage in sewerage and construction. For the purpose of designing this type of channel with the presumption of uniform flow, it is necessary to refer to Chezy and Manning relationships. In general, Chezy's and Manning's coefficients are given as data of the problem and are mostly considered constants regardless of the normal flow depth. This is an approximation of the fact that the flow resistance should vary with depth or hydraulic radius. In this study, the pipe is designed with a variable flow resistance coefficient, depending on the fill rate of the pipe. The Chezy coefficient is no longer data of the problem but a variable to be determined. The determination of Chezy's coefficient is made possible by the rough model method (RMM). The proposed sizing method is valid in the entire turbulent flow domain, encompassing smooth, transitional, and rough turbulent flow regimes in a wide practical range. [ABSTRACT FROM AUTHOR]

South Carolina's Beaufort‐Jasper Water and Sewer Authority optimized its wastewater systems using Partnership for Clean Water goals. [ABSTRACT FROM AUTHOR]

Sewer systems play vital roles in wastewater treatment facilities, and the microbial communities contribute significantly to the transformation of domestic wastewater. Therefore, this study conducted a 180-day experiment on a sewer system and utilized the high-throughput sequencing technology to characterize the microbial communities. Additionally, community assembly analysis was performed to understand the early-stage dynamics within the sewer system. The results demonstrated that the overall diversity of microbial communities exhibited fluctuations as the system progressed. The dominant phyla observed were Chloroflexi, Bacteroidetes, Firmicutes, and Proteobacteria, accounting for over 85.4% of the total relative abundances. At the genus level, bacteria associated with fermentation displayed a high relative abundance, particularly during days 75 to 180. A random-forest machine-learning model identified a group of microbes that confirmed the substantial contribution of fermentation. During the process of fermentation, microorganisms predominantly utilized propionate formation as the main pathway for acidogenesis, followed by acetate and butyrate formation. In terms of nitrogen and sulfur cycles, dissimilatory nitrate reduction and assimilatory sulfate reduction played significant roles. Furthermore, stochastic ecological processes had a dominant effect during the experiment. Dispersal limitation primarily governed the assembly process almost the entire experimental period, indicating the strong adaptability and metabolic plasticity of microorganisms in response to environmental variations. This experiment provides valuable insights into the metabolic mechanisms and microbial assembly associated with sewer systems. [ABSTRACT FROM AUTHOR]

During wet weather events, combined sewer overflows (CSOs) transfer large amount of particulate matter and associated pollutants into surrounding water bodies, thereby deteriorating the recipients' ecological health. Resuspension of sewer sediments during these events contributes significantly to pollution level of these discharges. However, how much this in-sewer process contributes to CSOs' quality regarding microplastic (MP) pollution is little known. Therefore, an investigation on sewer deposits inside the Parisian combined sewer network was carried out. The study found high MP concentrations stored in this matrix, ranging from 5 × 103 to 178 × 103 particle/kg dry weight. Polymer composition is similar to what found in raw wastewater, containing a high proportion of polyethylene and polypropylene. Thus, the results indicated the persistence of MPs in sewer network during transport during dry weather periods to treatment facilities. Once resuspension of sewer deposits happens, MPs can be released into water flow and get discharged along with CSOs. This highlights another potential pathway of MPs into freshwater environment. [ABSTRACT FROM AUTHOR]

This paper investigates the overflow oscillation elimination problem in the fixed-point two-dimensional (2D) digital filter (DF) based on Roesser model subjected to two's complement overflow (TCO) nonlinearities. By utilizing the system information and behavior of TCO nonlinearities more effectively, a new global asymptotic stability (GAS) criterion for 2D DFs is presented. A comparison of the obtained criterion with existing criteria is made with the help of examples. [ABSTRACT FROM AUTHOR]

Deep sound speed structure in the western Irminger Sea is found to be highly dynamic in comparison to the adiabatic (uniform) sound speed gradient underpinning data assimilation and modeling efforts around the globe. A beamed source parabolic equation model is used to illustrate how the resulting non-uniform sound speed structure at 1 to 1.5 km in depth and sound speed inversion near the seafloor produce observable effects on acoustic signals between a shallow source and shallow vertical line array at convergence zone ranges. Beamforming analysis shows that a uniform sound speed gradient leads to "ideal" interference patterns that do not capture or represent modeled convergence zone properties, such as location, strength, and sharpness. Overall findings suggest that in situ information about sound speed below 1 km is necessary for low frequency, long-range propagation studies, particularly in areas of complex thermohaline circulation. [ABSTRACT FROM AUTHOR]

Owen Gingerich's previously unpublished autobiographical sketch of his astronomical education, from his teenage years up through graduate school at Harvard, is presented with an introduction and notes by the editors. [ABSTRACT FROM AUTHOR]

The occurrence of combined sewer overflow (CSO) is a pressing environmental issue in many cities. This study aims to predict CSO occurrence using rainfall event characteristics, including rainfall depth, maximum intensity, and duration, and to determine which characteristic is the best predictor. Buffalo, New York, was selected as a case study. The results indicate that the prediction accuracy ranges from 80% to 100% for rainfall depth and maximum intensity, while rainfall duration is not a good predictor. Furthermore, rainfall depth is more likely to be the best predictor for sewersheds with a larger area. Additionally, combining the three rainfall event characteristics using the decision tree can only improve the average prediction accuracy slightly, from 93% (using a single characteristic) to 95% (using three characteristics). Using rainfall event characteristics and this simple method can be an effective alternative to complex urban hydrological models and/or expensive monitoring for predicting CSO occurrence. [ABSTRACT FROM AUTHOR]

Wastewater-based epidemiology (WBE) has great potential to monitor community public health, especially during pandemics. However, it faces substantial hurdles in pathogen surveillance through WBE, encompassing data representativeness, spatiotemporal variability, population estimates, pathogen decay, and environmental factors. This paper aims to enhance the reliability of WBE data, especially for early outbreak detection and improved sampling strategies within sewer networks. The tool implemented in this paper combines a monitoring model and an optimization model to facilitate the optimal selection of sampling points within sewer networks. The monitoring model utilizes parameters such as feces density and average water consumption to define the detectability of the virus that needs to be monitored. This allows for standardization and simplicity in the process of moving from the analysis of wastewater samples to the identification of infection in the source area. The entropy-based model can select optimal sampling points in a sewer network to obtain the most specific information at a minimum cost. The practicality of our tool is validated using data from Hildesheim, Germany, employing SARS-CoV-2 as a pilot pathogen. It is important to note that the tool's versatility empowers its extension to monitor other pathogens in the future. [ABSTRACT FROM AUTHOR]

A hydraulic jump phenomenon is exciting in turbulent flow as it causes large-scale turbulence and high-energy loss. This paper investigates the hydraulic jump characteristics of right triangular prism rough beds. The renormalization group RNG k-ε turbulent model and the volume of fluid (VOF) method in a CFD model are utilized to simulate hydraulic jumps. A total of 210 numerical simulations of four new types of rough beds were performed with an initial Froude number (Fr1) ranging from 4.8 to 9.4, the non-dimensionless wave steepness values of 0.67 ≤ t/s ≤ 1.33, and the distances between roughness elements of 0 ≤ Ls/y1 ≤ 2.67. This study found that arranging the right triangular prism rough elements in a stilling basin increased bed shear stress and energy loss. At the same time, they reduced sequent depth and jump length by about 22% and 50% compared to a smooth bed, respectively. In addition, the entropy production rates are also used to analyze energy dissipation, which clearly shows that the characteristic shape of a rough bed significantly influences the hydraulic jump length. Equations and plots that specify the relationships between the hydraulic jumps and study parameters are helpful guidelines for defining the rough bed dimension when designing or repairing a stilling basin for low-head irrigation works and highway sewers. [ABSTRACT FROM AUTHOR]

Steep creek hazards are characterised according to their solid fraction, νs, which governs the flow dynamics. To arrest these hazards, rigid multiple barriers are installed along a channel. However, existing design guidelines are deficient because the fundamental overflow and landing mechanisms are not well understood. In this study, experiments were conducted using a 5 m long flume to model the impact of flows with different νs values on a rigid barrier. By varying the νs of sand–water mixtures, the dynamics of different steep creek hazards were modelled. The barrier height was varied to obtain barrier Froude numbers Frb (ratio of flow inertia to potential energy related to barrier height) from 0·7 to 3·4. Results show that barriers should be designed so that Frb < 1, which leads to downward overflow with reduced landing distances. In addition, the landing distance for the watery flows (νs = 0 to 0·1) is up to 87% longer than that of dry granular flows. This implies that the design spacing between barriers should cater for different types of steep creek hazards and Frb. An existing framework for multiple barriers is modified to provide guidance on the selection of the barrier height using the Frb. [ABSTRACT FROM AUTHOR]

When the Brooklyn Waterworks opened in 1859, it was one of America's most advanced water and sewer systems. Yet after Brooklyn was annexed by New York City, the waterworks' history slipped into obscurity, despite having a now-famous champion: the "poet of America," Walt Whitman, whose brother worked on the project. This article shows the Brooklyn poet's fierce, multiyear lobbying effort for the waterworks in various newspapers and introduces a wealth of newly recovered Whitman writings on the issue. As a journalist, Whitman exemplifies the nineteenth-century press as an intermediary between expert engineers and popular readers. The poet brought precise expertise, translated engineers' technical arguments into everyday language for his readers, and fought the resulting day-to-day political battles over construction in print. Whitman, then, is an underappreciated case study of the confluence of technology, public health, and local journalism. [ABSTRACT FROM AUTHOR]

Heavy-metal ions (HMIs) as a pollutant, if not properly processed, used, and disposed of, will not only have an influence on the ecological environment but also pose significant health hazards to humans, making them a primary factor that endangers human health and harms the environment. Heavy metals come from a variety of sources, the most common of which are agriculture, industry, and sewerage. As a result, there is an urgent demand for portable, low-cost, and effective analytical tools. Bionanosensors have been rapidly developed in recent years due to their advantages of speed, mobility, and high sensitivity. To accomplish effective HMI pollution control, it is important not only to precisely pinpoint the source and content of pollution but also to perform real-time and speedy in situ detection of its composition. This study summarizes heavy-metal-ion (HMI) sensing research advances over the last five years (2019–2023), describing and analyzing major examples of electrochemical and optical bionanosensors for Hg2+, Cu2+, Pb2+, Cd2+, Cr6+, and Zn2+. [ABSTRACT FROM AUTHOR]

China's urban drainage pipeline systems and pipeline inspection technologies have achieved significant progress in the past 40 years, whereas the existing drainage pipelines are facing damage, defects, and aging, and thus have received growing attention. To better understand the underlying reasons for the development of China's urban drainage pipeline systems, and improve the utilization efficiency of pipeline inspection technologies, this research comprehensively analyzed the development process of China's urban drainage pipeline systems in terms of the spatio-temporal characteristics of pipeline length, the types of sewer lines, existing problems and consequences. Moreover, the widely used pipeline inspection technologies were presented and compared, and appropriate inspection techniques were proposed for pipelines that are difficult to detect with the common techniques. Finally, specific suggestions and future developments were provided for the construction, defect inspection and condition assessment, and management and maintenance of urban drainage pipeline systems. This review will hopefully assist in the management and maintenance of China's urban drainage pipeline systems, and provide a valuable experience and practices for other developing countries. [ABSTRACT FROM AUTHOR]

The inactivation kinetics of total coliforms to increase the pathogenic removal efficiency in a full‐scale ozonation contactor in a wastewater treatment plant in Algeria is investigated. An enhanced ozone contactor design is proposed and 3D multiphase computational fluid dynamics simulations were conducted to optimize the operating parameters, including flow rates, ozone concentrations considering the treatment performance, and total operating cost. The existing design has several limitations, including poor mass‐transfer efficiency and uneven distribution of dissolved ozone. To address these issues, the optimized design includes new injection‐point settings and an increased number of diffusers. The optimized design achieved a significant improvement in mass transfer efficiency. The ozone treatment effectively reduced the total coliform counts in the wastewater samples compared to the existing design. The Chick‐Watson model predicted inactivation kinetics, with a reduction of up to 99.997 %. The practical implications of this research can significantly improve the inactivation kinetics of ozone treatments. [ABSTRACT FROM AUTHOR]

This paper presents a flexible framework that aims at estimating the risk of structural failure in sewer pipes by utilizing limited or imperfect data. To this end, classical risk analysis is enhanced by incorporating fuzzy logic and multi-criteria decision making. To account for the multi-dimensionality of collapse risk at the pipe level as a decision parameter, its distinct impacts on the environment, traffic and road condition, and quality of life are taken into account. The proposed method is applied to the sewer network of Tehran, the capital of Iran. Results show how the integration of different risk indexes can influence the criticality of pipelines for the selection of rehabilitation activities. While using the first individual risk index, only considering the risk posed to the natural environment by a collapsing pipe in terms of contamination, approximately half of the pipe lengths are classified as extremely critical by the clustering algorithm. However, when the integrated risk is calculated, this cluster encompasses only approximately 30% of the total pipe length. With a database that contains various levels of uncertainty (from 10 to 60%), the predictive reproducibility for the exact same risk cluster is above 20% and above 50% for the same or only marginally better or worse. Furthermore, pipelines that are predicted to have a better risk class than the situation without considering uncertainty, thereby underestimating the likelihood of failures or consequences, are below 15%, showing a measure of quite good robustness. Considering the budget constraints of utilities, the proposed method can be applied to any urban, aiding in the identification of high-risk sections. Nevertheless, incorporating physical validation might be beneficial for further improving the analysis. [ABSTRACT FROM AUTHOR]

Groundwater pollution poses a significant threat globally, particularly in developing countries where inadequate sanitation facilities contribute to growing concerns about contamination from sewer leaks. Hence, the objective of this study is to present a comprehensive review, offering insights into diverse aspects of sewer leaks and their impacts on the urban groundwater system. This includes an exploration of leak sources, methods for leak detection, quantification approaches, analysis of contaminants in sewage along with their health effects, and strategies for mitigating both sewer leaks and groundwater contamination. This review addresses various factors leading to sewer infrastructure damage, emphasizing its importance in effective maintenance strategies. In this review, a range of contaminants released from sewer leaks were outlined, ranges from emerging contaminants to heavy metals that poses risk to the human health and environment. Further it evaluates various methods for detecting sewer leaks, emphasizing advancements in water quality analysis, visual, electromagnetic, and acoustics techniques. This research assesses diverse techniques for quantifying sewage leaks, including mass balance and wastewater balance and concludes pinpointing specific leak hotspots remains challenging. Furthermore, an appraisal of mitigation measures was also conducted, determining that rehabilitation serves as a more effective approach to stop leaks at their source. This paper delves into groundwater treatment methods, highlighting the difficulties in achieving optimal water quality and reveals that technologies such as Permeable Reactive Barrier and advanced oxidation processes exhibit potential in effectively removing trace-level pollutants. Overall, the review underscores the importance of understanding, detecting, and mitigating sewer leakage for the health and sustainability of groundwater systems. [ABSTRACT FROM AUTHOR]

The effects of longitudinal inclined plates and perforated inlet baffle on the settling efficiency and the overall hydrodynamics of a rectangular sedimentation tank are investigated using computational fluid dynamics. Five new cases of modified geometry have been thoroughly analyzed for this study. To simulate the multiphase flow, the Euler–Lagrange method is adopted by using the Discrete Phase Model. Experimentally obtained particle size distribution data of a potable water treatment plant and an industrial wastewater treatment are used to examine the effectiveness of the modifications in improving the settling efficiency. The longitudinal inclined plates are found to be highly effective in increasing the settling efficiency by increasing the settleable area, while the perforated baffle is found to be useful in dissipating the kinetic energy from the influent and helps in achieving plug-flow conditions in the sedimentation tank. It was also found that the controlled recirculation currents may be beneficial for settling fine particles. [ABSTRACT FROM AUTHOR]

This paper proposes a method for reducing the environmental impact of sewer network (SN) overflows. The main objective of the paper is to minimize the wastewater quantity and the pollutant loads that overflow from the SN. The proposed algorithm to achieve this goal is Model Predictive Control using Particle Swarm Optimization as optimization method. It was tested in simulation using a simplified model of the network based on Benchmark Simulation Modelsewer as prediction model, and a forecasted influent. Three cases have been considered: (a) the fitness function is defined as the global yearly overflow volume calculated using equal weights for each tank; (b) the fitness function uses different weights for each tank depending on the medium loads and (c) integrating a penalty term related to the system state at the end of the prediction horizon in the previous fitness function. The simplified model determined a significant reduction of the integration time minimizing the optimization time. Key Points: Model Predictive Control is used to reduce pollution caused by sewer network (SN) overflowsSimplified SN flow model decreases the optimization time of the control algorithmPollutant loads are assessed by the control algorithm by weighting overflow volumes with values calculated based on offline measurements [ABSTRACT FROM AUTHOR]

Overflow is usually used to keep fluid continuously flowing to avoid the fluid from changing flow direction and subsequently inducing large stresses. To explore the mechanism of flow‐induced stress evolution, a flow model was established in terms of compressible, non‐isothermal, and viscoelastic flow. Based on the Leonov model and the mid‐plane approach, a pseudo‐Poisson type equation for pressure was derived to decouple the interdependence between velocity and pressure. To improve computational efficiency, a numerical approach involving double iterations was proposed to solve the flow problem. Two kinds of mold cavities, with and without overflow, were designed and manufactured. Molding experiments were conducted, and corresponding simulations based on the proposed model and algorithm were performed. The results show that the simulated contours of flow‐induced stress are in good agreement with the photoelastic streaks. The use of overflow can significantly reduce flow‐induced stresses. If the slot thickness is set to a proper value, the flow‐induced stress can be reduced by more than 80%. On the other hand, a slot that is too thick does not have significant reducing effects. Therefore, using overflow to reduce flow‐induced stresses during transparent part production is a promising approach if the material cost is worthy of the quality. Highlights: A double iteration method is proposed for viscoelastic flow problem.Overflow can reduce the stress as much as 80% if the dimension is properly set.The simulated stress streaks are in good agreement with photoelasticities. [ABSTRACT FROM AUTHOR]

The paper analyses the results of water flow modelling in the urban drainage system of the city of Trebišov, Slovakia. The purpose of the work was to assess the risk of flooding in the urban area and its reduction using Green Infrastructure (GI). The complex hydraulic and hydrological modelling software MIKE+ was used in the research. Using the model of the city's urban drainage system, water flow simulations were carried out using short-term block rainfall events of varying intensity, lasting from 15 to 120 minutes and with return periods of 2 to 10 years. For each scenario, the number of flooded manholes was determined. As a result, areas where two types of GI could be implemented were identified and included in the surface runoff hydrological model. In this study, two types of GI were used: semipermeable pavements and green roofs. The stormwater flow was modelled under four scenarios: current status, implementation of semipermeable pavements, green roofs and their combination. The model results were compared to the current conditions. It was found that the application of both types of GI could potentially reduce the number of flooded points by more than 30 % for short-term rainfall with a return period of two years. As the return period of the short-term rainfall increases, the number of flooded points decreases to an average value of 5%. [ABSTRACT FROM AUTHOR]

Introduction: Lymphatic filariasis is a neglected tropical disease (NTD) caused by microscopic worms that live only in the human lymphatic system. Physical environmental factors play a role in preventing filariasis, especially the presence of breeding places and contact with mosquitoes. The aim of this study was to describe agent, vector, and physical environment risk factors such as bed net usage and sewerage conditions for lymphatic filariasis in developing countries. Discussion: This study was conducted using the narrative literature review method. The main sources for this study were articles from Google Scholar, Research Gate, PubMed, Springer, Scopus, and DOAJ databases with the criteria published between 2012 and 2022, observational studies including cross-sectional, casecontrol, and cohort designs, open access, and articles were organized according to STROBE guidelines. Out of the 100 articles identified, only 14 articles fulfilled the predetermined criteria after undergoing screening and removal of duplicate articles. The study was carried out in a group of developing country, including India, Myanmar, Indonesia, Nigeria, Ethiopia, Democratic Republic of Congo, Republic of Congo, Zambia, and United Republic of Tanzania. Wuchereria bancrofti is the most common agent of lymphatic filariasis. Culex and Anopheles are the vectors. The presence of bed nets and sewerage conditions were physical environment risk factors for lymphatic filariasis in developing countries. Conclusion: The use of mosquito nets or insect repellent at night can prevent lymphatic filariasis. In addition, open drains should be cleaned regularly to prevent them from becoming breeding sites for mosquito as vectors. [ABSTRACT FROM AUTHOR]

Wastewater pipelines are largely buried underground, and techniques for assessing and visualizing their condition are critical for planning and rehabilitation. This paper introduces a framework for integrating Geographic Information System (GIS), 3D-creation platform, augmented reality (AR) techniques, and machine learning algorithms for the dynamic visualization of the condition of sewer networks. A sewer network in Ålesund City, Norway, was used as a case study, and the developed framework was implemented on an Android OS and Microsoft HoloLens. The results show the potential applications of the integrated framework of GIS, AR, and 3D models for sewer condition visualization. The positioning accuracy of the application for 2D objects is equivalent to that of well-designed GPS receivers (approximately 1–3 m), depending on the handheld device used. Loading and locating 3D objects will be limited by the performance of the devices used. [ABSTRACT FROM AUTHOR]

How did Civil Society Organizations (CSOs) globally address the needs caused by the COVID-19 pandemic? In this study, we examine the roles CSOs played during the first 18 months of the pandemic, their main challenges, and how the pandemic changed CSOs' roles in society across 39 countries and economies. Using inductive thematic analysis analyzing responses from global philanthropy experts in two consecutive studies (2020 and 2021), we find that CSOs played fourteen roles, of which we discuss the six most mentioned: providing social assistance; responding to health care needs; coordinating and collaborating with government and business; mobilizing funds to address societal needs; raising awareness and combating misinformation; and advocating. Challenges for CSOs included reduced revenue and difficulty reaching beneficiaries. We found these challenges led to innovative ways of operating and new arrangements between civil societies and governments, which may have opened opportunities for a more active role of CSOs. [ABSTRACT FROM AUTHOR]

Premature failure of two upward-inclined underground pipes carrying sewage caused sinkhole formation in a busy urban road. Metallurgical failure analysis revealed that the pipes were made of ductile cast iron. External and internal coatings were appropriate to protect the pipes from external soil and internal sewage slurry corrosion. Partial filling of sewage slurry during the pumping recess allowed turbulent flow in the empty section during pumping, and the impact of turbulence eroded the internal coating, i.e., mortar lining, introduced erosion–corrosion and progressively reduced the pipe wall thickness in the upper half of the pipes resulting to weakening. Intermittent turbulence led to some localized corrosion fatigue-induced fracture in the weakened pipe wall. Erosion–corrosion with the assistance of corrosion fatigue led to the premature failure of the ductile cast iron pipes. [ABSTRACT FROM AUTHOR]

This paper aims to develop a sediment deposits hydraulic deterioration model based on self-cleansing criteria to prioritize the inspection of sewer systems. The model was trained with benchmarking literature values from earlier experiments and validated with household connections complaints data from Bogotá, Colombia. Recursive Feature Elimination with Cross-Validation (RFECV) and Bayesian Optimization (BO) were used to construct a Random Forest (RF) model to predict, at pipe level, the likelihood for a pipe to present sediment deposits. To evaluate the model's prediction accuracy, two different performance indicators were used: (i) the Percentage of Effective Inspections, and (ii) Pipes per Inspection with sediments. The sediment deposits hydraulic deterioration model shows good overall performance with buffer zones radiuses of 250 m predicting which pipes tend to present sediment deposits over time. This model improves the understanding of sediment deposits in hydraulic deterioration models and can be used to prioritize inspection of sewer systems. [ABSTRACT FROM AUTHOR]

The loss coefficient is one of the most critical parameters in computing the hydraulic grade line of sewer systems. The head loss coefficient of a manhole is dependent on various hydraulic and structural characteristics, such as manhole mold, connection angle, and the ratio of manhole diameter to pipe diameter. Three different manhole molds, flat, half-bench, and full-bench, and connection angles of 180°, 90°, and 135° are investigated, where the manhole diameter to pipe diameter ratio is 5.3. This paper presents the results of experimental and numerical investigations focused on determining the loss coefficient for two-way straight-through and angled manholes. The flow structure inside the chimney is the significant parameter for the magnitude of the energy loss coefficient. The head loss coefficient is almost constant under the surcharged flow conditions for all kinds of manholes. In terms of head loss coefficients, half-channel manholes do not have a significant advantage over flat-bottomed manholes in the cases of 135° and 90° flow inputs. The full-bench bottom manhole head loss coefficient is the smallest. The computational fluid dynamic modeling results agree with the experimental studies. [ABSTRACT FROM AUTHOR]

Sampling and analysing urban wastewater are found to be a reliable indicator of the regional spread of infectious diseases. During the COVID-19 pandemic, several research groups around the globe sampled wastewater from treatment plants or other points throughout a sewer system and tried to identify the presence of the virus. Since infected persons are found to excrete the virus in their feces and urine, urban wastewater analysis proved to be a valuable tool for the early detection of spikes in the disease. In the present study, an effort was made to investigate several fate and transport scenarios of SARS-CoV-2 in a sewer system. USEPA's Storm Water Management Model (SWMM) was utilized for the analysis. The modelling results were then used as an input to an optimization procedure using an NSGA-II algorithm. The optimization procedure aimed to determine the appropriate number and combination of sampling points for a better assessment of the disease's dispersion in the community. Four to six sampling points seem to offer a high likelihood of SARS-CoV-2 RNA detection in minimum time, representing the maximum population. [ABSTRACT FROM AUTHOR]

Featured Application: The potential applications of the research results, particularly the models utilizing ensembles of neural networks, offer the feasibility of early cost estimates for sewerage projects. The cost estimates of construction works, derived from the developed models, can be generated based on the essential features of sewerage projects that are accessible for analysis prior to the commencement of detailed design. This paper presents research results on the development of an original cost prediction model for construction costs in sewerage projects. The focus is placed on fast cost estimates applicable in the early stages of a project, based on fundamental information available during the initial design phase of sanitary sewers prior to the detailed design. The originality and novelty of this research lie in the application of artificial neural network ensembles, which include a combination of several individual neural networks and the use of simple averaging and generalized averaging approaches. The research resulted in the development of two ensemble-based models, including five neural networks that were trained and tested using data collected from 125 sewerage projects completed in the Czech Republic between 2018 and 2022. The data included information relevant to various aspects of projects and contract costs, updated to account for changes in costs over time. The developed models present satisfactory predictive performance, especially the ensemble model based on simple averaging, which offers prediction accuracy within the range of ±30% (in terms of percentage errors) for over 90% of the training and testing samples. The developed models, based on the ensembles of neural networks, outperformed the benchmark model based on the classical approach and the use of multiple linear regression. [ABSTRACT FROM AUTHOR]

Leaky urban drainage networks (UDNs) exfiltrating wastewater can contaminate aquifers. Detailed knowledge on spatiotemporal distributions of water-dissolved, sewer-borne contaminants in groundwater is essential to protect urban aquifers and to optimize monitoring systems. We evaluated the effect of UDN layouts on the spreading of sewer-borne contaminants in groundwater using a parsimonious approach. Due to the UDN's long-term leakage behavior and the existence of non-degradable sewer-borne contaminants (equivalent to a conservative and constant contaminant source), we employed a concept of horizontal line sources to mimic the UDN layout. This does not require the consideration of bio-degradation processes or temporal delay and effectively bypasses the vadose zone, thus reducing computational requirements associated with a full simulation of leakages. We used a set of synthetic leakage scenarios which were generated using fractals and are based on a real-world UDN layout. We investigated the effects of typical leakage rates, varying groundwater flow directions, and UDN's layouts on the shape of the contaminant plume, disregarding the resulted concentration. Leakage rates showed minimal effects on the total covered plume area, whereas 89% of the variance of the plume's geometry is explained by both the UDN's layout (e.g., length and level of complexity) and groundwater flow direction. We demonstrated the potential of applying this approach to identify possible locations of groundwater observation wells using a real UDN layout. This straightforward and parsimonious method can serve as an initial step to strategically identify optimal monitoring systems locations within urban aquifers, and to improve sewer asset management at city scale. [ABSTRACT FROM AUTHOR]

While the main focus of numerous engineering-geological investigations is to determine load-bearing capacity and settlement in engineering structures, this article aims to point at the specificity of sewer system engineering-geological investigations, which focuses on workability of soils and rocks. The study deals with workability class assessment of seven different sewer system localities. The significance of this research lies in the mutual comparison of workability class assessment of these seven localities in terms of two different workability standards. Each of the standards represents an independent model of assessment and classification of workability. The first standard (CSN 73 1001) classifies soils and rocks into seven workability classes, while the second (EN ISO 14688) comprises only three workability classes. Each of the approaches has its advantages and disadvantages. In comparison to the first one, the second standard permits faster and easier classification of rocks, but may be less fair to investors or developers when considering the real engineering-geological conditions and costs of implementation. Rocks were newly classified into three (easy, medium and difficult) categories of earthwork realization difficulty. In the study, 33 layers were classified in the category of easy realization of earthworks, 8 layers in the category of a medium degree of earthwork realization difficulty, and two layers in the category of a difficult realization of earthworks. [ABSTRACT FROM AUTHOR]

A novel method is developed and demonstrated for identifying the dominant component of rainfall-driven infiltration and inflow (I&I) in sanitary sewers. The method uses synoptic measurements of rainfall, sewer flow rates, and water-table elevations to extract the ratio of infiltration to total I&I as a function of rainfall amount. The method is based on three quantifiable relations: the incremental flow rates resulting from rainfall events of different magnitudes, the responses of the water-table elevations to rainfall events of various magnitudes, and the responses of dry-weather flow rates to changes in water-table elevations. Application of the method is demonstrated at 10 locations in South Florida. The results show that infiltration is the dominant mechanism for small rainfall events at five of the 10 locations, and inflow is the dominant mechanism for large rainfall events at nine of the 10 locations. [ABSTRACT FROM AUTHOR]

Identification and control of the pollutant load in sewer networks (SNs) are among the priorities for utilities to reduce the impact on water bodies and to individuate the presence of pathogens to prevent their further spread, sometimes through interventions on a social scale. This goal can be achieved essentially through the development of a monitoring system. This paper proposes a backtracking methodology for efficiently planning a monitoring system in SNs assuming steady-state conditions during the analysis. The methodology is based on the calculation of the impact coefficient, which is related to the dilution and decay of contaminants and pathogens in the network, to evaluate the impact of each possible contaminated node on a downstream one in terms of concentration. This information supports the identification of candidate monitoring points, i.e., where to place measurement sensors to ensure complete coverage and control of the network. Additional analysis has been performed considering unsteady conditions for comparing the impact coefficient values averaged over 24 h and those of the steady-state methodology. Results show a similar value between steady-state and unsteady conditions, thus justifying the use of steady-state conditions for the proposed methodology, and also for real practical applications, with a significant improvement in terms both of simplicity and computational time saving. [ABSTRACT FROM AUTHOR]

This study investigated the effect of environmental parameters on microbial-induced concrete corrosion during three corrosion stages. The corrosion effects and influencing factors in three corrosion stages were deeply analyzed and predicted, and the mechanism of microbial corrosion was summarized. When the H2S concentration was lower than about 15.0 mg/m3, the corrosion was maintained in stage II, which greatly delays the intensification of corrosion. In stage III, the H2S concentration has the significantly accelerate the corrosion rate. Additionally, incorporating min, max and mean values of input parameters greatly improved the accuracy of machine learning predictions of corrosion rates (R2 >0.99). Acidithiobacillus was found to be dominant in the microbial community at H2S concentrations of 12.0–37.5 mg/m3, and increased temperature promoted the reproduction of Acidithiobacillus. [ABSTRACT FROM AUTHOR]

Stormwater surcharge events are unavoidable above a certain rainfall intensity. Thus, for protection and damage mitigation, forecast systems are of outstanding importance. This study develops an ensemble forecast system (EFS) to predict the beginning and end of sewer surcharge events. It applies a nonlinear autoregressive with exogenous inputs (NARX) network to each member of the ensemble, making it suitable for real-time predictions. The fundamental idea is the forecast of water depth time series within manholes based on the given rainfall. The novelty lies in the consideration of uncertainty through the ensemble structure for which the numbers of neurons in the hidden layer, the weights, and biases are considered to be uncertain. The results are evaluated based on observed values captured within the uncertainty band (P f a c t o r ), and the width of the band (R f a c t o r ). The P f a c t o r varied between 74% and 94% and the R f a c t o r between 1.36 and 10.68. [ABSTRACT FROM AUTHOR]

In order to better plan new or update sewer pipe condition assessment protocols, this paper presents systematic comparisons of four of the most widely used sewer condition assessment protocols, including the fourth edition of the Sewer Rehabilitation Manual (SRM-4) in the UK, the Pipeline Assessment and Certification Program (PACP) in America, the Sewer Physical Condition Grading Protocols (SPCCM) in Canada, and the Technical Specification for Inspection and Evaluation of Urban Sewer (TSIEUR) in China. In the qualitative comparison, the defects categories, deduct values, and assessment methods of the four protocols are analyzed. A new concept of defect weight is firstly introduced to make comparisons between protocols applicable and easy; in the quantitative comparison, the protocols are used to evaluate the same 182 sewer pipe segments based on field data and the assessment results are compared. It is found that the main reasons for the different evaluation results are due to the different defect weights and evaluation methods used. Finally, PACP shows obvious advantages and is recommended for asset managers when making new or updating protocols in the future. [ABSTRACT FROM AUTHOR]

The maintainability of sewer infrastructure systems is vital for public health, environmental protection, and the overall well-being of communities. However, maintenance and repair activities for sewer pipelines are often constrained, leading to challenges in effectively managing such infrastructures. To address these challenges, this study assessed the maintainability of sewer pipelines. A total of 15 defects were identified and categorized into structural, hydraulic, and quality defects after a comprehensive literature review was conducted and sewer pipeline experts were interviewed. Each failure caused by these defects was categorized as a pipe collapse associated with structural defects, sewer system overflow (SSO), odor, and groundwater contamination associated with quality defects. Apart from assessing the defects, the study identified potential solutions. After that, the obtained data were analyzed to determine the relative significance of each probability identified and its impact on four parameters, economic, social, environmental, and detection difficulty, using the relative importance index (RII), while the risk value index (RI) was applied to prioritize the defects. Furthermore, a data reliability assessment was utilized to evaluate internal consistency. The findings indicate that the probability of joint defects in the structural category caused by weaknesses in welded joints due to the misalignment of plastic pipes or joints, especially spigot and socket joints for rigid pipes, was the highest (RII = 0.733). Additionally, the ranking showed that the dumping of FOG had the highest priority, with an RI value of 0.535. This study offers a comprehensive maintainability framework that can be utilized by agencies assessing their current sewer infrastructure systems, in particular Arab Gulf countries including Saudi Arabia, which is the subject of this study. [ABSTRACT FROM AUTHOR]

Forecasting of wastewater treatment plant inflow dynamics constitutes an enabler technology for wastewater treatment process optimization using model predictive control. However, accurate inflow prediction is still challenging, especially for strong rainfall events, where complex system dynamics and missing information on future rainfall represent limiting factors. We propose a seasonal probabilistic time series model for modeling the short‐term wastewater inflow accurately while providing quantification of forecast uncertainty. To ensure suitability for practical implementation, the unconstrained parameters of the predictive distribution are modeled as linear functions of the input variables in the framework of Generalized Additive Models for Location Scale and Shape. Non‐linear effects are approximated by Rectified Linear Units, accounting for buffering within the sewer network and flow‐dependent catchment response time. In addition to water level measurements from within the sewer network and rain rate measurements, rain forecasts are incorporated as exogenous regressors, where historical rain forecasts are used for model calibration. The model performance is evaluated on historical data from a German wastewater treatment plant using deterministic and probabilistic scoring rules. We benchmark against an autoregressive time series model and a long short‐term memory artificial neural network. Our results show that the proposed model unites the benefits of high prediction accuracy of the neural network and enhanced intelligibility of the autoregressive model, but accurate real‐time rain forecasts are mandatory for successful real‐world implementation. Plain Language Summary: The wastewater treatment process accounts for a large proportion of a wastewater treatment plant's energy consumption. Here, an accurate prediction of future wastewater inflow is an important tool for the optimization of energy efficiency. The potential for optimization is particularly large for rain events. However, especially in such situations, inflow prediction is most challenging. We developed a specialized computer algorithm for inflow prediction that utilizes weather forecasts in order to produce reliable inflow predictions in such situations. The developed algorithm is a machine learning model that learns the knowledge needed to perform accurate predictions from historical data. Although capable machine learning models are generally complex, we aimed to design the algorithm in such a way that it is understandable and hence trustworthy for practitioners so that it can easily be used in real‐world application. We tested the algorithm and our results show that it is possible to generate precise wastewater inflow predictions, but very accurate and quickly available weather forecasts are mandatory, which is an interesting objective for further research. Key Points: We propose a model for probabilistic wastewater treatment plant inflow prediction utilizing rain forecast data to handle rain eventsNon‐linear dynamics within the sewer system are approximated in a linear framework using rectified linear unitsOur results indicate similar performance to less intelligible non‐linear models, but rain forecast accuracy constitutes a limitation [ABSTRACT FROM AUTHOR]

This paper proposes a method to include drop manholes in the optimal design of sewer networks. These structures dissipate energy and reduce flow velocity, which is important in hilly regions where high slopes induce velocities that exceed the maximum allowable. The methodology proposed here introduces a new type of arc to represent drop manholes in a model that uses graph theory to achieve the minimum cost design of a sewer network. Also, for the estimation of drop manhole costs, a new cost function is developed based on pipe and manhole cost equations proposed in the literature. The methodology was tested in eight different series of pipe configurations, as well as a real sewer network located in Colombia, varying the pipe material and the land slope. The results demonstrated that the proposed methodology allows for the optimal design of sewer networks in hilly regions while satisfying all hydraulic and commercial constraints. [ABSTRACT FROM AUTHOR]