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Urban pluvial floods are characterised by a number of features such as the high spatial and temporal resolution needed to capture their dynamics, the complexity of dual drainage systems and the lack of sewer data availability, which make them very different from other types of floods, like coastal or fluvial floods, and which increase the difficulty of modelling them. As a consequence, most flood management plans do not include a rigorous evaluation of urban pluvial flood risk. In this paper, we give a comprehensive view of the current state of urban pluvial flood modelling, not restricted to a mere description of the mathematical approaches, but also including the most relevant features that should be considered in their modelling, the validation studies that have been performed to date and our vision on the modelling challenges that should be addressed in the near future. [ABSTRACT FROM AUTHOR]

The coexistence of multiple defect categories as well as the substantial class imbalance problem significantly impair the detection of sewer pipeline defects. To solve this problem, a multilabel pipe defect recognition method is proposed based on mask attention-guided feature enhancement and label correlation learning. The proposed method can achieve current approximate state-of-the-art classification performance using just 1/16 of the Sewer-ML training data set and exceeds the current best method by 11.87% in terms of F2 metric on the full data set, while also proving the superiority of the model. The major contribution of this study is the development of a more efficient model for identifying and locating multiple defects in sewer pipe images for a more accurate sewer pipeline condition assessment. Moreover, by employing class activation maps, our method can accurately pinpoint multiple defect categories in the image, demonstrating strong model interpretability. [ABSTRACT FROM AUTHOR]

Worldwide population growth is accelerating, which is driving up demand for essential items to meet demands. As time goes on, an increase in need has resulted in system degradation and deterioration because of an increase in global warming and a reduction in the amount of resources that are accessible. For humans to survive on Earth, water is a vital component. To properly collect, transmit, treat, store, distribute, and dispose of potable water and wastewater, a well-developed infrastructure is necessary. The water supply and sewage systems include fittings, transfer pumps, reservoirs, water channels, and piping systems. Systems for pipelines, reservoirs, water channels, transfer pumps, and fittings make up the water supply and sewage systems. Reinforced concrete, steel, ductile iron, asbestos cement, and reinforced concrete were used as materials for water delivery pipelines. Such systems require significant time and financial investment to build. The phenomenon of delays, which is recognized as one of the most common issues in the sector, has an impact on the building industry globally. This study investigates the impact of inflation on construction materials, particularly cement, used in water supply and sewerage infrastructure projects. Through a comprehensive survey of twelve construction industry stakeholders, the research identifies that inflation leads to significant cost overruns and project delays. These delays are primarily due to increased material costs, procurement delays, and conflicts among stakeholders. The study highlights that the rising prices of building materials reduce the purchasing power of clients and stakeholders, causing delays in material procurement and extending project timelines. To mitigate these effects, the research suggests promoting domestic purchases over imports and managing resources efficiently. The findings underscore the importance of considering inflation rates in project budgeting and recommend developing a budget estimation model that accounts for fluctuating material prices due to inflation. [ABSTRACT FROM AUTHOR]

Methane (CH4) emissions from urban sewer systems represent a significant contributor to greenhouse gases, driven by anaerobic decomposition processes. This review elucidates the mechanisms underlying CH4 production in sewers, which are influenced by environmental factors such as the COD/SO42− ratio, temperature, dissolved oxygen, pH, flow rate, and hydraulic retention time. We critically evaluated the effectiveness of empirical, mechanistic, and machine learning (ML) models in predicting CH4 emissions, highlighting the limitations of each. This review further examines control strategies, including oxygen injection, iron salt dosing, and nitrate application, emphasizing the importance of balancing CH4 reduction with the operational efficiency of wastewater treatment plants (WWTPs). An integrated approach combining mechanistic and data-driven models is advocated to enhance prediction accuracy and optimize CH4 management across urban sewer systems. [ABSTRACT FROM AUTHOR]

Uneven access to water and wastewater infrastructure is shaped by local governance. A substantial number of U.S. households lack adequate access and the U.S. is one of the few countries with large populations living outside of city bounds, in unincorporated areas. Few studies address how infrastructure services and local governance are intertwined at a regional scale. We examine the connection between incorporation status and access to centralized infrastructure, using negative binomial regression. A novel dataset informs this analysis, comprised of 31,383 Census block groups located in nine states representing over 25% of the national population. We find evidence that inequities in access are associated with unincorporated status and poverty rates. Sewer coverage rates are significantly lower for unincorporated communities in close proximity to municipal boundaries. Infrastructure equity could be improved by targeting high-poverty unincorporated communities, addressing challenges with noncontiguous service areas, and strengthening regional water planning and participatory governance. [ABSTRACT FROM AUTHOR]

Introduction: The advancement of antimicrobial resistance is a significant public health issue today. With the spread of resistant bacterial strains in water resources, especially in urban sewage, metagenomic studies enable the investigation of the microbial composition and resistance genes present in these locations. This study characterized the bacterial community and antibiotic resistance genes in a sewage system that receives effluents from various sources through metagenomics. Methods: One liter of surface water was collected at four points of a sewage channel, and after filtration, the total DNA was extracted and then sequenced on an NGS platform (Illumina® NextSeq). The sequenced data were trimmed, and the microbiome was predicted using the Kraken software, while the resistome was analyzed on the CARD webserver. All ecological and statistical analyses were performed using the. RStudio tool. Results and discussion: The complete metagenome results showed a community with high diversity at the beginning and more restricted diversity at the end of the sampling, with a predominance of the phyla Bacteroidetes, Actinobacteria, Firmicutes, and Proteobacteria. Most species were considered pathogenic, with an emphasis on those belonging to the Enterobacteriaceae family. It was possible to identify bacterial groups of different threat levels to human health according to a report by the U.S. Centers for Disease Control and Prevention. The resistome analysis predominantly revealed genes that confer resistance to multiple drugs, followed by aminoglycosides and macrolides, with efflux pumps and drug inactivation being the most prevalent resistance mechanisms. This work was pioneering in characterizing resistance in a sanitary environment in the Amazon region and reinforces that sanitation measures for urban sewage are necessary to prevent the advancement of antibiotic resistance and the contamination of water resources, as evidenced by the process of eutrophication. [ABSTRACT FROM AUTHOR]

Detecting defects in complex urban sewer scenes is crucial for urban underground structure health monitoring. However, most image-based sewer defect detection models are complex, have high resource consumption, and fail to provide detailed damage information. To increase defect detection efficiency, visualize pipelines, and enable deployment on edge devices, this paper proposes a computer vision-based robotic defect detection framework for sewers. The framework encompasses positioning, defect detection, model deployment, 3D reconstruction, and the measurement of realistic pipelines. A lightweight Sewer-YOLO-Slim model is introduced, which reconstructs the YOLOv7-tiny network by adjusting its backbone, neck, and head. Channel pruning is applied to further reduce the model's complexity. Additionally, a multiview reconstruction technique is employed to build a 3D model of the pipeline from images captured by the sewer robot, allowing for accurate measurements. The Sewer-YOLO-Slim model achieves reductions of 60.2%, 60.0%, and 65.9% in model size, parameters, and floating-point operations (FLOPs), respectively, while improving the mean average precision (mAP) by 1.5%, reaching 93.5%. Notably, the pruned model is only 4.9 MB in size. Comprehensive comparisons and analyses are conducted with 12 mainstream detection algorithms to validate the superiority of the proposed model. The model is deployed on edge devices with the aid of TensorRT for acceleration, and the detection speed reaches 15.3 ms per image. For a real section of the pipeline, the maximum measurement error of the 3D reconstruction model is 0.57 m. These results indicate that the proposed sewer inspection framework is effective, with the detection model exhibiting advanced performance in terms of accuracy, low computational demand, and real-time capability. The 3D modeling approach offers valuable insights for underground pipeline data visualization and defect measurement. [ABSTRACT FROM AUTHOR]

Freud's article on the uncanny also includes the concept of the double. According to Freud, this concept points to the duality in the construction of the ego in the primary narcissism period, when the child acquires the understanding of moral control. This duality results from the splitting of the ego and creates an area where unwanted material is pushed into the subconscious. However, this repressed area carries traces of the ego because it was once part of it. Similarly, in Neil Gaiman's Neverwhere (1996), London Above and London Below, as a divided city, represent the ego and the repressed space that emerges as a result of the split of the ego. London Above represents a politicized morality in which a fixed class structure is accepted, for example, the Upsiders not seeing the Downsiders, or Jessica's urge to appear in art galleries with Richard. As a representation of self, London Above embraces positive materials, while London Below functions as "the other" or "evil twin" because this space, accessed through doors or sewers, is dark, damp, and smelly. London Below also contains the repressed and unwanted social dynamics of London Above. However, since the doppelgänger is a division of a whole, the suppression of the undesirable underclass is also mimicked in London Below, thus resulting in a recurring matrix of social hierarchy in both cityscapes. In this context, this study aims to analyse the doppelgänger motif in relation to the class-based basin of London. [ABSTRACT FROM AUTHOR]

A common method for measuring sewer and drainage manholes with tape measure lacks precision in cases of sediment accumulation or deep manholes, impacting data accuracy. This paper proposed a method for measuring sewer and drainage manholes using terrestrial laser scanning. This method first utilizes a plane fitting equation and the RANSAC method to determine the ground and segmentation planes, enabling automatic trimming of the point cloud of the manhole. Subsequently, the pipe's inlet and outlet extraction is done using the point cloud combining Region Growing method. Finally, according to the feature of cylinder pipe and elliptical cylinder pipe, the inlet and outlet are reconstructed using the extracted point cloud. Experimental results show that the radius of pipe's inlet or outlet can be measured by the proposed method with an accuracy of 5.20 mm, the height difference of the manhole can be measured with an accuracy of 7.05 mm, meeting the requirement of a permissible deviation of 10 mm for measuring the lowest point of manhole specified in the " Code for construction and acceptance of water and sewerage pipeline works " (GB50268-2008). [ABSTRACT FROM AUTHOR]

To manage night soil, establishing a modern sewerage system is necessary, but its completion takes a long time. If night soil is not appropriately managed, a city can immediately become paralyzed. How do governments manage night soil prior to the completion of a sewerage system in modern society? This paper describes the contemporary policy history of night soil management for the twenty-three wards of Tokyo, which is a unique and informative case. The Tokyo Metropolitan Government (TMG) attempted to maintain the traditional system of managing night soil, which was delivered to farmland as a source of agricultural fertilizer until the 1960s. Because the demand for artificial chemical fertilizers has dramatically increased across Japan since the 1960s, the TMG was forced to depend on dumping night soil into the sea to keep Tokyo clean. In 1967, the leftist and liberalist Ryokichi Minobe was elected governor on a promise to promote welfare and environmental policy. However, he saw no choice but to dispose of night soil into the sea until the completion of a modern sewerage system. The transition in the management of night soil, from delivering it to farmland to disposing of it in the sea, was a considerable change, but the decision was made within the scope of routine administrative work. This paper presents a detailed study of the management of a social nuisance in the field of policy history. [ABSTRACT FROM AUTHOR]

This study investigates public attitudes towards the use of human excretion-based fertiliser (HEBF) in agriculture. Focusing on England and Japan, countries with contrasting histories of nightsoil use, we conducted representative surveys to understand public acceptance and sex-based differences in attitudes. Our findings reveal significant cultural and sex-based disparities in the willingness to utilize HEBF. The Japanese are more accepting of using HEBF for food production, with fewer health concerns, compared to the English. However, English respondents are more open to using HEBF in public parks. The study emphasises the need for further research on societal perceptions and highlights the importance of cultural context in adopting sustainable practices like HEBF in agriculture.

Closed-circuit television (CCTV) inspections are essential in keeping sewer pipe performance at a desirable level. A sewer pipe condition score is usually assigned to each pipe based on the type, quantity, and extent of defects observed through CCTV inspections. Although the impact of different factors on the condition score has been considered in several studies, the effect of these factors on the underlying defects has yet to be investigated. The aim of this study was to investigate the effect of various potential influencing factors on the prevalence of eight defect categories (gas attack, material damage, infiltration, roots, debris, total joint, structural, and dipped pipe) in the transmission sewer network of Auckland, New Zealand. A cleaned data set with the defects identified through recent CCTV inspections of 2,780 sewers was gathered and linked to various physical and environmental factors. Results identified insightful and statistically significant relationships between defect categories and factors that provide new insights into the drivers of deterioration processes in sewer pipes. [ABSTRACT FROM AUTHOR]

This paper is dedicated to the issues of human activity on sanitary ‘frontier’ from antiquity to present. The structure of the article is determined by the initially put forward hypothesis about the unconditional relationship between the stages of civilizational development and technical level of sewers of ‘frontier’ states: centers of science, technology, and culture. We used systemic approach: development of sewerage systems was analyzed chronologically; the importance of environmental engineering “city-river” systems were noted; and the stages of formation of sewers in the largest centers at industrial era, as well as the need for their modernization in connection with deterioration of environmental situation and corresponding demand of society were considered separately. Although contemporary sewer systems are one of the most amazing inventions of mankind, the contradictions inherent to these systems have not yet been resolved on a global scale. The authors conclude that many of the problems that faced the largest cities in developed countries in the past are now facing the capitals and agglomerations of developing countries. Echoes of the medieval unsanitary conditions can be found everywhere in today’s settlements, and sewer systems of the world’s largest industrial centers often correspond to Victorian London in the level of development and perfection. There is an increasing need for a fundamentally new approach to organizing engineering systems while maintaining and, in some cases, increasing the level of hygiene and sanitation. Digital technologies will become increasingly important. The paper is intended for the readers interested in development of certain areas of management, – in this case it is the sphere of sewerage, – and their impact on the human habitat.

Wastewater treatment plant (WWTP) influent sampling is commonly used in wastewater-based disease surveillance to assess the circulation of pathogens in the population aggregated in a catchment area. However, the signal can be lost within the sewer network due to adsorption, degradation, and dilution processes. The present work aimed to investigate the dynamics of SARS-CoV-2 concentration in three sub-catchments of the sewer system in the city of Hildesheim, Germany, characterised by different levels of urbanisation and presence/absence of industry, and to evaluate the benefit of sub-catchment sampling compared to WWTP influent sampling. Our study shows that sampling and analysis of virus concentrations in sub-catchments with particular settlement structures allows the identification of high concentrations of the virus at a local level in the wastewater, which are lower in samples collected at the inlet of the treatment plant covering the whole catchment. Higher virus concentrations per inhabitant were found in the sub-catchments in comparison to the inlet of the WWTP. Additionally, sewer sampling provides spatially resolved concentrations of SARS-CoV-2 in the catchment area, which is important for detecting local high incidences of COVID-19. [ABSTRACT FROM AUTHOR]

The present work aims to investigate the effect of pipe roughness on the construction cost of sewer networks in steep terrains. To achieve this objective, a sensitivity analysis was performed, wherein a sewer network was designed with different pipe roughnesses and varying terrain slopes to simulate four distinct steep terrains. In addition, this study considers the effect of new pipes with very high roughnesses that have appeared on the market in recent years, evaluating their influence on sewer network design and construction cost in steep terrains. The sewer networks were designed using an existing methodology for an optimal design that includes drop manholes if required to meet all the hydraulic constraints. The effect of pipe roughness was tested in two sewer networks from distinct sectors of Bogotá, Colombia. Practical Applications: This study has relevance when considering its ability to lead to the expansion of the sewer service, particularly in hilly regions. The use of higher roughness pipes as a result of this finding has a direct impact on reducing the need for drop manholes, leading to a significant reduction in associated costs. This reduction in costs is of paramount importance in the viability and execution of sewer projects in communities facing significant financial constraints. By minimizing costs, this approach not only optimizes project efficiency but also facilitates access to basic sanitation services in geographic areas previously considered difficult to address. Consequently, this research not only improves sewer systems but also contributes to community development. [ABSTRACT FROM AUTHOR]

Fieldwork was carried out in the western area of Edmonton, Alberta, Canada to assess the H2S contribution of a long force main and to investigate the source of H2S generation in a complex sewer network. The study sewer trunk has a length of 10 km, a diameter of up to 1.95 m, and flow rate of up to 0.6 m3/s. In the upstream, there is a 5.6 km forcemain, and the pump station operation can cause a sudden increase of H2S in the sewer air of the discharge manholes to reach 500 ppm. Wastewater samples were collected in 14 manholes in the sewer network and analyzed for sulfide and other relevant parameters. The maximum values of sulfide were 9.7 mg S/L and pH remained mostly neutral. For predicting the sulfide generation rate, an empirical model was applied with readily biodegradable organic matter. Then the emission of H2S in gravity pipes was investigated, and it was found over 90% of H2S stayed in the liquid phase when wastewater flowed in gravity sewer pipes. Finally, the mass transfer in a drop structure of 8 m was investigated. The liquid phase H2S concentration in the upstream was 2.6 times that of the downstream, and about 62% of the H2S was released in this drop structure indicating the significant emission of H2S in drop structures. [ABSTRACT FROM AUTHOR]

The ten Water and Sewerage Companies covering England and Wales were privatized in 1989, primarily due to the financial pressures they faced from historic underinvestment and the need to comply with EU environmental-related legislation. In the first decade, this worked well as inland and bathing water improved. More recently, environmental progress has been seen under a harsher light due to a number of factors, many of which reflect poorly on the way these companies are managed and regulated. A number of potential responses are put forward. [ABSTRACT FROM AUTHOR]

Municipal wastewater may contain toxic substances that have a negative impact on biological treatment processes and receiving waters. This paper presents the wastewater toxicity test results from the Lodz hybrid sewage system. Wastewater is discharged to surface waters through a treatment plant, but also during wet weather, partially without treatment by combined sewer overflows. The research was carried out using the ToxTrakTM method with the use of the microbial community of activated sludge from the wastewater treatment plant in Lodz. The median toxicity, expressed as the degree of inhibition, ranged from 16.0% to 30.7%, but sometimes exceeded 50%. Higher toxicity was observed in wet weather than in dry weather. Seasonal variability was found but typical daily variability was not observed. In the case of sewage samples with the degree of inhibition above 40%, a significant correlation was found with chromium concentration and non-ionic surfactants (Pearson's coefficient correlation above 0.7). [ABSTRACT FROM AUTHOR]

This paper explores Hull's histories of living with water and flood in the period between the foundation of the town in the 1260s and c. 1700, examining how the inhabitants, Corporation and Commissioners of Sewers managed and governed water in order to survive and thrive in a risky yet resilient estuarine environment. It does that as part of a bigger project utilising 'learning histories' drawing on Hull's 800-year experience of living with water and flood to drive climate awareness and flood resilience in a city which has experienced major flooding in recent years and is increasingly vulnerable in the face of future climate change. Here, we use civic and other records to reconstruct a flood timeline for medieval and early modern Kingston-Upon-Hull, revealing a history of repeated flood events impacting the town and surrounding area in the centuries after its foundation in c. 1260. We explore who managed and governed water and flood risk, and how this was achieved, arguing that water management was a pervasive concern as well as a collective and shared responsibility which ultimately generated a 'living with water mentality'. [ABSTRACT FROM AUTHOR]

Determinations of radioactivity and stable element contents in outlet waters taken from dams (Çamlıdere, Kurtboğazı, Kesikköprü, Çubuk-2) and drinking waters from water treatment plants (İvedik, Pursaklar and Çubuk) of Ankara Water and Sewerage Administration (ASKİ) were performed by using MPC-9604 multi-detector alpha/beta (α/β) counting system, inductively coupled plasma–mass–mass spectrometer and graphite furnace atomic absorption spectrometer. Gross alpha and beta activity levels and element concentrations found in samples were compared with maximum permissible values given by World Health Organization, United State Environmental Protection Agency, Turkish Standards and Türkiye Regulation on Water for Human Consumption. [ABSTRACT FROM AUTHOR]

The 1950s ended with some of Auckland's most significant, and enduring, infrastructure completed, or approved and under construction, in a decade of impressive implementation of what had been just visions at its commencement. The enormous growth of the city made projects such as a harbour bridge, an international airport, a new sewerage system, and a roading network imperatives in the eyes of Auckland political and business leaders. Those leaders determined what they thought was best for Auckland and then applied consistent pressure on the Government to obtain approval, and where relevant, funding to proceed. This article investigates the processes by which these remarkable achievements occurred in what was rapidly becoming New Zealand's premium city. [ABSTRACT FROM AUTHOR]

Blockage detection in circular open channels (partially filled pipes, e.g., gravity sewer pipes) has gained increasing interest in the water industry. While there have been significant advancements in monitoring technologies for such systems (e.g., smart sewer systems), there is a lack of quantification of the hydraulic impact of partial blockages in circular pipes, which is a limiting factor for cost-effective detection. This study presents and validates a numerical framework to quantify the changes in water depth caused by extended bottom blockages in circular open channels. The analysis is based primarily on continuity and energy conservation with the assumption of a lossless transition at the blockage. The proposed approach can determine the critical blockage height that would induce choking, therefore a change in the upstream depth. It can also calculate the changed upstream water depth for various bottom blockage height values (above the critical height) for both subcritical and supercritical conditions. The proposed approach is numerically implemented and then validated through a series of laboratory experiments under the subcritical flow condition (which is the most common condition for gravity sewer systems). The numerically determined water depth results are consistent with the experimental results, which confirms that the proposed approach can accurately estimate the new upstream depth under the choking condition induced by a bottom blockage in circular open channels. The results contribute to advancing the hydraulic understanding in circular open channels with extended partial blockages, which is useful in the development of smart sewer technologies. Practical Applications: Spills and overflows out of the gravity sewer system damage the environment and bring risks to public health. The problem is typically caused by partial blockages, which can reduce the flow capacity of the sewer pipe and induce higher-than-designed flow depth on the upstream of the blockage (known as choked flow condition). This study helps water engineers and operators to understand how an extended bottom blockage affects the flow condition just upstream of the blockage in a circular gravity sewer pipe. Charts have been presented to enable the determination of (1) the critical height of an extended bottom blockage that would induce choking; (2) the expected upstream flow depth for blockages with various heights, with a given flow rate under choked flow condition; and (3) the expected upstream flow depth for various flow rates, with a given blockage height under choked flow condition. The results can be used to evaluate the risk of bottom blockage-induced spill for sewer pipes with various sizes, slopes and flow rates (e.g., some may be more tolerant to bottom blockages while some may be more sensitive). This information can then be used to prioritize preventative measures such as sewer depth monitoring or regular cleaning. [ABSTRACT FROM AUTHOR]

The potential for corrosion and odor emissions from a combined sewer interceptor system in Northwest Chicago was investigated. Seven manholes along the interceptor system were selected as monitoring locations, and eight critical physical-chemical and biological parameters were measured semiweekly at each location for four weeks during the morning and afternoon hours. Statistical analyses were performed to determine the diurnal variability of 5-day biochemical oxygen demand (BOD5), as well as the variability of total sulfide with respect to BOD5 and the sewer flow rates. Subsequently, the Pomeroy–Parkhurst mathematical model was used to predict the change in total sulfide concentration in a mile-long segment of the interceptor system. The model was calibrated by modifying the sulfide flux coefficient in the generation term to reflect the conditions in these interceptors, such that the measured values and model predictions were in agreement. A strong linear relationship between the system's wastewater flow and water quality characteristics and the modified sulfide flux coefficient was found (R2=0.828). With limited wastewater characteristic data, the modified Pomeroy–Parkhurst model can be used in predicting the change in total sulfide concentrations for this interceptor. [ABSTRACT FROM AUTHOR]

Traditional approaches devoted to upgrading the sewerage system functionality are highly costly and time demanding. Thus, the implementation of comprehensive modelling approaches can be intended as an effective and economically viable strategy to detect and outdo the critical issues of the networks. This paper presents an integrated procedure to monitor and simulate the network's performance, based on the coupling of Supervisory Control and Data Acquisition (SCADA) networks for data collecting and monitoring, with hydraulic simulations by the Storm Water Management Model 5.1 (EPA-SWMM) solver. The drawbacks of the network are then assessed by proposing several upgrades to improve the system. The proposed strategy was applied to the Nora-Noreña sewerage system, located in North Spain. Results show the potentiality of the methodology in reducing sewer network maximum filling degree requirements and overflows into the receiving water bodies. [ABSTRACT FROM AUTHOR]

The unplanned and rapid expansion of metropolitan areas reduces accessibility to existing and often outdated centralized water and wastewater systems. In this context, sanitation policies that focus exclusively on centralized systems become expensive and unfeasible. Using Q methodology, we identified three different social perspectives on onsite wastewater treatment systems (OWTS) in the metropolitan area of the Lerma Valley in northern Argentina. We focused our analysis on the legal, environmental, and technical aspects of onsite sanitation. The perspectives found were: 'OWTS have advantages', 'Hard path for sewerage', and 'Process before technology'. We describe the perspectives identified and we provide an analysis of their differences and similarities to discuss their possible policy implications for our study area and comparable regions in the country and beyond. [ABSTRACT FROM AUTHOR]

Key Takeaways: Biennial data from 2017 to 2023 show that water and sewer prices increased substantially, from an average combined monthly price of $79.39 in 2017 to $95.02 in 2023 at 6,200 gallons per month for single‐family residential customers. Water rate structures became more regressive during that time, with utilities collecting an increasing share of revenue through fixed charges and less revenue through volumetric charges. Average low‐income affordability in the United States has worsened over the past six years, mainly driven by extreme unaffordability in a small minority of utilities. [ABSTRACT FROM AUTHOR]

Combined sewer overflow (CSO) control strategies are commonly selected relying on optimization or multicriteria analysis. A methodology is proposed in this paper for selecting and evaluating the solutions to mitigate stormwater problems in combined sewer systems (CSSs) based on the understanding and rigorous diagnosis of the causes of the observed problems using hydrological/hydraulic simulations. The methodology was applied to a sewer catchment near Montreal (Canada) in order to reduce the magnitude and recurrence of sewer surcharge and local flooding without increasing the recurrence of CSOs. Two types of control strategies were considered: (1) large-scale solutions, i.e., redirection of stormwater inflows and separation of the CSS; and (2) source control solutions including both green and gray infrastructure. These solutions were evaluated through a comparative analysis of nine scenarios. Based on the results, source control solutions could be considered as the most effective interventions on the studied catchment for eliminating or significantly reducing the occurrence of sewer surcharge (from an average of 6.7 to 2.6) and surface flooding on local streets (from an average of 3.5 to 0.4 per year). The developed methodology is a valuable tool to be applied to other urban drainage catchments that encounter problems similar to those observed on the studied catchment. [ABSTRACT FROM AUTHOR]

During the appearance of the first snowfall, there is a revival of discussion on effective methods of protecting road surfaces and sidewalks against icing. In Poland and many other countries, so-called road salt, mainly sodium chloride (NaCl) with additives, is often used to lower the melting point of snow and ice. Using chemicals to protect road surfaces brings many negative side effects reported in the literature. Less frequently published research results indicate, and also alarm, that increased chloride concentrations can appear in wastewater flowing into sanitary (separate) sewers. In the case of small wastewater treatment plants, increased chloride concentrations can have a negative impact primarily on the biological processes of wastewater treatment and, after discharge from the wastewater treatment plant, on the biological life in the waters and the nearest recipient environment of the treated wastewater. The study aimed to determine the concentrations and loads of chlorides in wastewater flowing through the distribution sewer system to 4 small wastewater treatment plants located in Poland, in the Lesser Poland Province, during snowmelt and heavy rainfall in 2019–2023. The study showed a significant increase in concentrations and loads of chlorides in wastewater in February. Unit chloride load in raw sewage during snowmelt varied from 7 to 12 kg∙d–1 per 1 km length of separate sewer network. There was also a repeated, but much lower, increase in chloride con-centrations during summer and autumn precipitation. This is when the leaching of residual salt accumulated around the road surface occurred.

Aligning with the decarbonization roadmap of the EU and fifth-generation district heating systems, an exergy-based optimization and decision-making model was developed for minimum CO2 emission responsibilities. Nine environmental, thermal, and electromechanical constraints were applied. Seven cases are presented, including sewer heat in Bavaria and Toronto, Jincheon eco-friendly energy town, low enthalpy geothermal heat, a data center, waste incineration plant in Amsterdam, waste heat from the stack of a coal-fired power plant, and building-scale utilization of building wastewater. Sample calculations show that the maximum carbon footprint belongs to the sewer heat system, because of the larger temperature peaking requirement. The minimum carbon footprint belongs to the geothermal heat utilization system. [ABSTRACT FROM AUTHOR]

Infrastructure deterioration is a threat to developed countries, emphasizing the need for effective management techniques. In particular, the leakage of aged domestic sewer pipeline is a major health issue, yet there is a lack of markers to identify domestic leakage. We studied the pollution in urban waters resulting from domestic sewage leakage into storm drainages. We monitored caffeine, fragrance substances and polycyclic aromatic hydrocarbons (PAHs) in the storm discharge points in five urban districts having separate sewer systems aged from 10 to over 40 years. Results show that caffeine and fragrance concentrations tended to increase with sewer system age. For instance, caffeine concentrations in the areas of sewer systems over 40 years old were at least two orders of magnitude higher than in 10-year-old sewer systems, and were as high as 1–10% of domestic sewage, strongly suggesting the leakage of domestic sewer pipelines. PAHs exhibited consistent patterns across the districts. Overall, we observe that sewer leaking processes can be distinguished by analyzing the levels of organic pollutants. [ABSTRACT FROM AUTHOR]

Air in the headspace of sewer laterals can be driven by the flowing sewage as well as air pressure. In this study, the openings on manholes for air flow are approximated as a thin continuous slot at the laterals. In this way, the governing equations can be solved analytically for infinitely long laterals without water flow. For cases with water flow, a numerical solution is developed. It is found that the air flow pattern in a long lateral can be categorized into three zones. The zone closest to the trunk is defined as the "zone of influence," where the air flow in the lateral is dominated by air pressure, and the air pressure and air velocity decay exponentially in the lateral. The second zone is named as "zone of equilibrium" where the air pressure gradient is zero and the air flow is only driven by the drag of water and can be calculated analytically. The air flow zone farthest from the trunk is defined as the "zone of induction" where the air is inducted into the system for mass balance in the system. An explicit fitting expression on the air velocity and water velocity in a long lateral is provided. A graphic solution for air velocity and zone of influence is also developed for a quick estimation on the air movement in sewer laterals. [ABSTRACT FROM AUTHOR]

This study conducted experiments to investigate the impact of bottom obstacles, specifically broad-crest weir-type and cylindrical obstacles, on the flow within a sewer pipe. It was observed that these two types of obstacles, when possessing the same cross-sectional area and length, exhibited nearly equivalent hydraulic responses for both supercritical and subcritical flows. The obstacle height was found to be the primary factor responsible for choking and the transition between different flow regimes. The results of the one-dimensional analysis show that the threshold value of obstacle height depends on the approaching flow conditions, including the Froude number and the filling ratio that is defined as the flow depth to the pipe diameter. In the context of a partially blocked sewer, the relationships established by using the one-dimensional model between the size of the bottom obstacle and the inflow characteristics enable the identification of flow regimes, assessment of reduced hydraulic capacity, and evaluation of local energy loss. The findings of this study elucidate the hydraulic behavior of obstructed sewers, contributing to the development of more effective strategies for the identification of obstructions through monitoring data. [ABSTRACT FROM AUTHOR]

Sewer concrete structures are vulnerable to acidic corrosion due to the biological oxidation of sulfide in the wastewater to sulfuric acid. The use of photosynthetic bacteria in the coating layer on the sewer concrete is proposed to be an effective approach to prevent such corrosion. Here we report two strains, PN6 and PN7, isolated from a drainage system in Hanoi that were identified as Rhodopseudomonas palustris PN6 and Rhodobacter capsulatus PN7 based on a comparative analysis of the 16S rDNA and pufM gene sequences. Both strains performed versatile metabolic paths, including anoxygenic and microaerophilic phototrophy and aerobic chemotrophy, allowing them to adapt to the fluctuating sewer conditions. Furthermore, they exhibited notable capability of oxidizing sulfide and producing glycocalyx, and therefore were able to prevent concrete corrosion by scavenging sulfide and reducing the production of sulfuric acid, at the same time sealing the tiny cracks on the concrete surface and preventing further attack of the corrosive agents. Two strains grew well at an alkali pH of 9 and formed biofilm extensively, and therefore can be incorporated into porous material vermiculite, allowing them to survive in the coating mortar. The protective effect of coating mortar containing strains PN6 or PN7 singly or in a combination of both incorporated in vermiculite was demonstrated in a laboratory model simulating the sewer environment with an acidic vapor atmosphere. Without bacteria in the coating mortar, the concrete surface suffered severe corrosion with spots of 0.01–0.2 mm in width and up to 4.5 mm in length clustering in rafts of 10–70 mm2 , whereas the concrete surface coated by bacteria-containing mortar was intact to corrosion. The study proposed the possibility of applying purple nonsulfur bacteria (PNSB) to protect sewer concrete, and also prolong the service life of these important structures. Practical Applications: Sewer concrete systems are daily attacked by acidic corrosion established via the biological oxidation of sulfide to sulfuric acid. The repair is generally costly and has difficulties in implementation. The use of PNSB with the capabilities of scavenging H2S and producing exopolysaccharide (EPS) for the development of a coating layer would be a feasible approach to constrain the corrosion process. Suitable strains of PNSB such as the two strains Rhodopseudomonas palustris PN6 and Rhodobacter capsulatus PN7 reported in this study are supposed to be incorporated in a porous material like vermiculite before being added to the coating mortar to better stabilize and adapt to the harsh conditions of the coating layer. These types of PNSB can survive in the coating layer and multiply by utilizing organic carbon and sulfide from wastewater with the production of sulfur (instead of sulfuric acid) and glycocalyx that can instantly seal the tiny corrosion spots and prevent further corrosion attacks. This approach is supposed to be a prevention solution to increase the service durability of sewer concrete systems and reduce the need for repair implementation. [ABSTRACT FROM AUTHOR]

This study partially replaced the clay with sewer sludge (SS) and rice husk (RH-SS) to make fired bricks. The brick samples were examed in terms of shrinkage, water absorption, and compressive strength. Besides, they were analyzed via XRD and metal extraction to determine the heavy metal residuals in the products. The results showed that it was possible to fabricate fired bricks using sewer sludge or rice husk-blended sludge with up to 30% by weight. These brick samples complied with the technical standard for clay brick production, in which the compressive strength was more than 7.5 MPa, water absorption was from 11–16%, and the linear shrinkage was all less than 5%. The rice husk addition helped mitigate the heavy metal residuals in the bricks and leaching liquid, in which all the values were lower than the US-EPA maximum concentration of contaminants for toxicity characteristics. Implications: Previous studies have proved the possibility of mixing sewage sludge from different origins (sewage sludge, river sediment, canal sediment, sewer sediment, etc.) with clay and some wastes to make bricks. In which, mostof the studies used sewage sludge from wastewater treatment plants, very fewdealt with lake/river or sewer sediment. This study shall be the first to study the possibility of employing sewer sediments with the addition of rice husk powder to achieve two targets, including (1) the reuse of biowaste and sludge for brick fabrication and (2) the reduction of heavy metals in final calcined bricks. Different ratios of the rice-husk blended sewer sludge (RH-SS) – clay mixture shall be tested to find the optimized compositions. The results showed that it was possible to fabricate fired bricks using sewer sludge or rice husk-blended sludge with up to 30% by weight, which meant reduce 30% of clay in the brick production. The final products were proved to meet the quality standard in terms of compressive strength (more than 10 MPa), water absorption(from 11–16%), and the linear shrinkage (less than 5%). Larger scale of this study can be an evident to recommend for policy change in the waste reuse in construction field. [ABSTRACT FROM AUTHOR]

This paper presents a Fault-Tolerant Model Predictive Control (FTMPC) algorithm applied to a simulation model for sewer networks. The aim of this work is to preserve the operation of the predictive controller as much as possible, in accordance with its operational objectives, when there may be anomalies affecting the elements of the control system, mainly sensors and actuators. For this purpose, a fault detection and diagnosis system (FDD) based on a moving window principal component analysis technique (MWPCA) will be developed to provide an online fault monitoring solution for large-scale complex processes (e.g., sewer systems) with dynamically changing characteristics, and a reconfiguration algorithm for the MPC controller taking advantage of its own features such as constraint handling. Comparing the results obtained considering various types of faults, with situations of normal controlled operation and with the behavior of the sewer network when no control is applied, will allow some conclusions to be drawn at the end. [ABSTRACT FROM AUTHOR]

The article presents information on the history of the Environmental Protection Agency (EPA). The EPA was aware that water and sewer services are essential for neighborhood livability and understood the significant costs associated with their upkeep and development. Yet, despite recognizing that its grant program had major implications for racial segregation in land use, the EPA treated civil rights as optional rather than mandatory. The author states that this approach mirrored the evasion of responsibility seen in other federal agencies, as highlighted by Christopher Bonastia, who noted that civil rights often lack meaningful enforcement when they become politically or economically costly. The EPA’s inaction, despite knowing the harm caused by its grants, underscores the deep connections between environmental protection and structural racism.

This article explores how innovation logics infiltrate problem and value definitions in maintenance and repair, and how innovation itself depends on considerable, often invisible care work beyond the seemingly smooth entrepreneurial narratives. We build on a growing body of work in STS that investigates the relationship between innovation and maintenance and repair. This literature argues that the obsession with innovation crowds out attention to maintenance, that innovation creates future obligations of maintenance that are often not factored into technological promises, and that ordinary maintenance and repair practices are often innovative in their own right. Empirically, we explore a case where maintenance and repair become the explicit target of high-level, high-tech innovation initiatives and how, as a result, innovation logics colonize maintenance practices. Conceptually, we explore how repair and maintenance sensitivities can be applied to innovation practices to reveal the invisible work needed to align innovation instruments with socio-material and institutional configurations. Drawing on an in-depth case study of sewer inspection robots in Barcelona, we find that attempts to innovate maintenance require a symmetric effort to maintain innovation. In our case study, innovation processes as deployed by the European Commission, research consortia, and companies required substantial repair work to function reliably in specific settings. Our study shows how divergent understandings of the public good in innovation and maintenance contexts may lead to significant tensions, and that much can be gained analytically from not treating innovation and maintenance as opposites. [ABSTRACT FROM AUTHOR]

This paper proposes a methodology for the optimal design of series of sewer pipes including pumping stations. It employs a Shortest Path Algorithm to select the optimal combination of pipe diameters and invert elevations, as well as the optimal pumping features such as the number of pumps, location, and pumping head. The methodology is intended to be applied to the design of any sewer series. Although these are uncommon in real infrastructure, the study allows an analysis of the effect of pipe roughness, inflows, and pipe length on the total cost of the system and pumping features. The methodology was tested in theoretical series of 10 and 20 pipes as well as in a real series that is part of the sewer system of Bogotá, Colombia. The resulting designs suggested that using smooth pipes and reducing the pumping flow rate would decrease the cost of sewer systems in flat terrain. [ABSTRACT FROM AUTHOR]

Disasters caused by heavy rainfalls are of growing concern to researchers and government officials. While many studies have provided details of rainstorm-induced risks and efficient strategies for stormwater management, there is still a lack of attention to how the interactions between urban sewer systems and road networks during precipitation events affect sewer system performance and road inundation. To fill this gap, we have developed an integrated model that combines hydraulic characteristics and the topological structure of a sewer-road network system to explore the behaviour of these two interdependent systems and identify risk components during precipitation events. We apply the model to a watershed during different return periods of precipitation events in Cincinnati, Ohio, USA. The results reveal that the behaviour of some inconspicuous pipes has a significant impact on the sewer-road network system, resulting in a significant decrease in the system performance. Moreover, the interactions between road and sewer networks create multiple microstructures of connected components, which leads to different risks of interdependent systems and road inundations. The modelling results provide target areas for mitigation projects to reduce rainstorm-induced risks. [ABSTRACT FROM AUTHOR]

IntroductionThe advancement of antimicrobial resistance is a significant public health issue today. With the spread of resistant bacterial strains in water resources, especially in urban sewage, metagenomic studies enable the investigation of the microbial composition and resistance genes present in these locations. This study characterized the bacterial community and antibiotic resistance genes in a sewage system that receives effluents from various sources through metagenomics.MethodsOne liter of surface water was collected at four points of a sewage channel, and after filtration, the total DNA was extracted and then sequenced on an NGS platform (Illumina® NextSeq). The sequenced data were trimmed, and the microbiome was predicted using the Kraken software, while the resistome was analyzed on the CARD webserver. All ecological and statistical analyses were performed using the. RStudio tool.Results and discussionThe complete metagenome results showed a community with high diversity at the beginning and more restricted diversity at the end of the sampling, with a predominance of the phyla Bacteroidetes, Actinobacteria, Firmicutes, and Proteobacteria. Most species were considered pathogenic, with an emphasis on those belonging to the Enterobacteriaceae family. It was possible to identify bacterial groups of different threat levels to human health according to a report by the U.S. Centers for Disease Control and Prevention. The resistome analysis predominantly revealed genes that confer resistance to multiple drugs, followed by aminoglycosides and macrolides, with efflux pumps and drug inactivation being the most prevalent resistance mechanisms. This work was pioneering in characterizing resistance in a sanitary environment in the Amazon region and reinforces that sanitation measures for urban sewage are necessary to prevent the advancement of antibiotic resistance and the contamination of water resources, as evidenced by the process of eutrophication.

During the discharge of floodwater from a hydropower station, a significant number of water droplets in motion are created in the downstream space. These droplets vary in size and velocity, causing challenges in determining the particle size and velocity distribution of the flood discharge atomized droplets. Currently, the particle-size distribution and velocity distribution of atomized droplets are considered to be independent, and the gamma function is used to describe the particle-size distribution and velocity distribution of droplets separately. However, a joint distribution of atomized droplet size and velocity is lacking. This paper uses the basic theory of maximum entropy to study the combined distribution of droplet size and velocity in the atomized flow caused by jet overflow. The present model was in a good agreement with experimental data, providing a method for the theoretical study of droplet size and velocity distribution in flood discharge atomization. [ABSTRACT FROM AUTHOR]

A sewer system is a principal element of infrastructure in modern cities, accounting for massive amounts of public investments. Corrosion of manholes in the sewer system is a global issue, and millions of dollars are being spent on the maintenance, restoration, and replacement of deteriorated sewer networks. Concrete manholes in the sewer system are deteriorating due to the attack of sulfuric acid produced by microorganisms in a process termed microbial induced concrete corrosion (MICC), which reduces the lifespan of concrete sewer elements. The objective of this paper is to investigate the correlation between the gas- and liquid-phase sewer environmental factors and hydrogen sulfide concentration in the gas phase. The production, emission, and build-up of hydrogen sulfide gas in manholes is identified as a major cause of MICC in manhole shafts. The field study was conducted in more than 200 manholes in the City of Arlington (Texas, US). The data was collected every minute for 48 h to understand the trends of liquid- and gas-phase parameters such as hydrogen sulfide (H2S concentration), liquid and gas temperature, pH, DO, and relative humidity. The study also examines how gas-phase H2S concentrations vary with season; manhole design, including manholes' depth, slope, and presence of drop; and sewer flow conditions such as velocity and turbulence. Although no strong linear correlation was found between liquid-/gas-phase parameters, the manhole categories were found to play a significant role in H2S generation. The manholes with hydraulic jump generated the highest average H2S concentrations, followed by manholes with drops. High turbulence zones were observed in manholes of both categories, leading to H2S stripping from liquid to gas phase. The highest H2S concentration was recorded in summer, suggesting that higher liquid temperature resulted in increased bacterial activity, which generated greater liquid-phase sulfide. Greater Henry's law constants in summer, due to high temperatures, would have favored transfer of liquid-phase sulfide to the gas phase. [ABSTRACT FROM AUTHOR]

Risk assessment lies at the core of decision making practices, relying on the likelihood of failure incidents and their consequential impacts integrated through a set of decision rules. The incorporation of fuzzy inference systems (FIS) into risk assessment has been proven to elevate the management and sustainability of infrastructures by reducing uncertainties in decision making and mimicking human decisions. Its parameters, primarily the fuzzy sets, are conventionally defined heuristically to align with the visions and objectives of decision makers or through clustering methods if data are available. However, utilizing these methods is insufficient for the comprehensive adoption or finetuning of input-output relationships, and it does not adequately address the incorporation of future changes in decision makers' opinions due to its inability to self train. To overcome this challenge, a Mamdani-based neurofuzzy system is proposed and modified for best practice in risk assessment, and a framework is developed for compiling the required training data set. Additionally, modifications in the training process include adding Lagrange equality constraints to the objective function and testing different optimizers to maintain the fuzzy logic and reduce the computational cost, respectively. The validation of the model's ability to learn the knowledge base and parameters of fuzzy set membership functions was conducted through training simulation on generic data developed from a predefined knowledge base, as explained in a case study. The data serve as an idealization or simulation of any risk data set that can be generated using the proposed framework. The model has confirmed its ability to learn the knowledge base from which the data are generated and the corresponding parameters of membership functions toward the comprehensive adoption of input-output relationships. This emphasizes the model's capability to learn the knowledge base from any risk data set developed using the proposed framework. Also, results have shown that the added constraints control the training process efficiently by maintaining proper interactions among fuzzy sets membership functions satisfying fuzzy logic; additionally, the Adam (adaptive momentum estimation) optimizer has reduced the training computational cost by more than 99%. Finally, to explain and validate the flexibility of the neurofuzzy model in risk assessment in adopting changes in the FIS hyperparameters and rules, the model was retrained after inducing three independent possible changes to the decision rules and the fuzzy sets. The model has proved its ability to grasp diverse decision maker requirements, giving more flexibility and broader implementation of FIS in risk assessment. [ABSTRACT FROM AUTHOR]

The Storm Water Management Model (SWMM) is a reliable software program for simulating stormwater runoff in combined drainage facilities. However, it faces challenges in efficiency, especially when executing real-time forecasting. This research explores an alternative machine learning (ML) approach to predict water levels in sewer and street drainage systems utilizing SWMM data for model training. The goal is to construct a hybrid ML model for urban flooding prediction, considering hydrological conditions, geomorphologic properties, and drainage facility features. A robust training method is introduced to deliberate complex flow conditions. The suggested approach achieves favourable performance in predictive accuracy and computational efficiency. Findings include: (1) similarity between ML and SWMM flooding depth on street nodes increases from 62.3% to 96.2% with the proposed training; (2) the proposed model is about 50 times faster than SWMM in urban flood simulations; (3) reliable predictions from the ML model are demonstrated through four accuracy metrics. [ABSTRACT FROM AUTHOR]

Over the recent years, ever-increasing population growth and higher wastewater production has been a challenge for decentralized wastewater treatment plants (WWTPs). In addition, sludge treatment due to high cost for equipment and place make authorities to find a sustainable approach in both of economical and technical perspectives. One of the proposed solutions is transferring the sludge produced from decentralized WWTP to centralized WWTP. However, the appropriate proportional ratio of raw sludge to raw sewage is a challenge, otherwise, it make anaerobic conditions and sewage rotting along the sewer network based on permissible limit of dihydrogen sulfide (H2S) gas (5 ppm). In the present study, seven reactors with different ratios of sludge to raw sewage (0, 15, 20, 25, 50, 75, 100) were used to stimulate the feasibility of transferring Shahrake Gharb WWTP sludge along the wastewater transfer pipe to the centralized sewage treatment south Tehran WWTP plant in Tehran, Iran. The septic situation and H2S emission of different reactors within 7 h (Time to reach the compound in the south treatment plant) was analyzed by gas meter. The results indicated that the optimum ratio of sludge to raw sewage was 15% without H2S production during 7 h. In addition, due to the high volume of sludge produced by the Shahrake Gharb WWTP, the optimal ratio of lime to total solids (TS) in sludge (gr/gr) (0.6) increased the sludge loading rate from 15 to 30% without any H2S emission during the stimulation study period. Therefore, the lime stabilization and transfer of sludge from a decentralized WWTP to a centralized WWTP is a feasible way to manage the sludge and enhance the treatment capacity in local WWTP. [ABSTRACT FROM AUTHOR]

Risk analysis (including resilience analysis) of infrastructure requires models that describe the connection of components and subsequent flow dynamics. However, the detailed information needed to define these models may not be available, especially for small‐scale infrastructure that connect to every building. In this paper, we generate location‐specific small‐scale networks using detailed data that should always be available. We propose a general framework where we generate the network topology, we estimate the resource demand at each building, and we design the network components to meet the demands. This general framework is applicable to all types of infrastructure, but many procedures are specific to the type of network being generated. This paper develops the necessary procedures to generate sewer networks and illustrates the usage for an example network in a small study area in Seaside, Oregon. The proposed sewer network generator produces realistic sewer networks as compared to the real network of Seaside. [ABSTRACT FROM AUTHOR]