Combined Sewer Overflows

Municipal effluents are well-recognized as disrupting sexual differentiation and reproduction in mussels. However, the contribution to this problem made by rainfall combined with sewer overflow (increased by rain due to climate change) is not well understood. The purpose of this study was to compare the neuroendocrine effects of municipal discharge and rainfall overflow on caged endemic mussel Elliptio complanata. To this end, mussels were experimentally caged and placed for 3 months at a municipal effluent dispersion plume site and at overflow sites. Data revealed that downstream surface water contained some pharmaceuticals (caffeine and carbamazepine) and accumulated significant levels of heterotrophic bacteria, but these effects were not observed at the overflow sites. The principal effects observed at the downstream site were increased soft tissue mass (and gonad index), inflammation, and Vtg proteins in male mussels as determined by a novel immunostaining methodology. The rainf...

Sewage overflows (SOs) and Combined Sewer Overflows (CSOs) significantly contribute to the bacterial contamination of coastal waters, which is of especial concern for aquaculture, a growing industry worldwide. Hydrodynamic and water quality models were used to investigate impacts of CSO discharge frequency and duration, river discharge and tides on Escherichia coli levels at shellfish farming sites in the Dart Estuary (UK), being the employed methodology generally applicable. High E. coli contamination occurred during neap tides and high river discharges due to higher retention and lower bacterial decay. Synchronicity of CSO spills affected the duration of the pollution episodes rather than peak concentrations, more influenced by discharges of the neighbouring CSOs. During peak discharges, E. coli concentrations could be 10 times higher than during average flows. CSO spills were more frequent when rainfall was >20 mm. Model outputs combined with rainfall forecasts can indicate microbiological contamination risk in the aquaculture sites.  A 3D-hydrodynamic and E. coli dispersal model was developed for the Dart Estuary.  E. coli inputs from sewer overflows peak during neap tides and high river discharge.  E. coli concentration is highly dependent on the decay model.  Sewer overflow spills in the Dart are frequent when rainfall exceeds 20 mm.  Model can be used to predict E. coli contamination at shellfish farming sites.

Storm water overflows have an important impact on the environment in many European countries. Nowadays, a better knowledge of combined sewer overflows (CSOs) pollution is required for implementing measures to reduce these emissions. In this work, pollution flows mobilized during rainy events have been monitored and modeled in two urban catchments located in the city of Murcia (southeast Spain). For each analyzed event, rainfall volume, in-sewer turbidity and water flow depth have been continuously measured. Therefore, sets of pollutographs and hydrographs have been obtained for each event analyzed. Characteristic variables have been defined and obtained for each event such as the maximum concentration of turbidity, the total event rainfall, the previous dry weather period, the time to the peak of the hydrograph and to the peak of the pollutograph, among others. Relations between variables have been adjusted through a statistical model. The adjusted parameters are used to generate pollutographs that are compared with those measured in field. The present work provides tools to assist in the knowledge of pollution transported through sewer network during stormy events, suggesting the creation of design pollutographs which may facilitate the evaluation of measures to reduce urban runoff pollution.

Municipal effluents are well-recognized as disrupting sexual differentiation and reproduction in mussels. However, the contribution to this problem made by rainfall combined with sewer overflow (increased by rain due to climate change) is not well understood. The purpose of this study was to compare the neuroendocrine effects of municipal discharge and rainfall overflow on caged endemic mussel Elliptio complanata. To this end, mussels were experimentally caged and placed for 3 months at a municipal effluent dispersion plume site and at overflow sites. Data revealed that downstream surface water contained some pharmaceuticals (caffeine and carbamazepine) and accumulated significant levels of heterotrophic bacteria, but these effects were not observed at the overflow sites. The principal effects observed at the downstream site were increased soft tissue mass (and gonad index), inflammation, and Vtg proteins in male mussels as determined by a novel immunostaining methodology. The rainf...

Combined sewer overflow (CSO), discharged by sewers during rain events, is a major cause of surface water pollution. This work aimed at developing a compact CSO treatment process by filtration and cation/anion exchange and validating it with actual CSO in a real environment. Preliminary screening of several cation and anion exchange materials led to selecting a molecular sieve (MS13X) that retained ammonium with a 13.3 mg N g-1 capacity, and a layered double hydroxide (calcined Sorbacid 911) that removed phosphate with a 2.2 mg P g-1 capacity. For both materials, the development of a regeneration procedure allowed to perform several adsorption/regeneration continuous-flow cycles with actual CSO without adsorption performance losses. Packed bed heights were scaled-up to 60 cm without variations in performance. The combined filtration/cation exchange/anion exchange process, tested in a real wastewater treatment plant, led to removals ≥ 87 % for COD, BOD 5 , suspended solids, total P, total N, faecal coliforms, metals (Zn, Cu, Ni) and pesticides (desethyl-atrazine, desethyl-terbuthylazine). 1-μm microfiltration gave the highest contribution to the overall removals. The cation/ anion exchange process was essential to reach high removals of ammonium (72 %), phosphate (70 %), and total N (92 %). The design of a full-scale filtration/ion exchange unit resulted in a surface requirement of just 0.20 m 2 for each m 3 h-1 to be treated, and in a 2.7 € m CSO-3 operational & maintenance cost. This work represents a relevant step towards the development of a compact CSO treatment featuring limited land requirement and the possibility to withstand prolonged periods of dry weather.

正会員 博(工) 京都大学准教授 防災研究所(〒612-8235 京都市伏見区横大路下三栖東ノ口) 2 学生会員 京都大学大学院 修士課程 工学研究科(〒615-8540 京都市西京区京都大学桂) 3 正会員 博(工) 京都大学助教 防災研究所(〒612-8235 京都市伏見区横大路下三栖東ノ口) 4 正会員 工博 京都大学教授 防災研究所(〒612-8235 京都市伏見区横大路下三栖東ノ口) 5 正会員 博(工) 中部大学准教授 工学部(〒487-8501 愛知県春日井市松本町1200)

A compact combined sewer overflow (CSO) treatment unit is set up and evaluated in pilot-scale. The pilotplant consisted of flocculation, coagulation and a microsieving system followed by a disinfection unit with either O3 or ClO2. Efficiency of the pilot-plant was evaluated with respect to reduction of Escherichia coli, coliform bacteria and intestinal enterococci as well as removal of biocides. Results showed that 10 mg L-1 of ClO2 as disinfectant was sufficient to meet the European Union (EU) requirements as per Bathing Water Directive (2006/7 EC) while the same results were only achieved when higher O3 dose (20 mg O3 L-1) was applied. This study revealed that chlorine dioxide was the most effective disinfectant agent in reducing the number of bacteria to below the limits set by the EU Bathing Water Directive and that the pre-treatment used was highly efficient. Regarding biocides, the efficiency of the removal was highly dependent on the type of substance. However, ozone was foun...

Using combined sewer systems to handle excess stormwater runoff is common in older urban areas. Combined sewer overflow (CSO) events occur when hydraulic capacity is exceeded, and untreated wastewater discharges to surface waters. As urban population density increases, and more demand is placed on infrastructure, CSO events happen more often and cause serious environmental problems and public-health risks. Recently, green infrastructure (GI) has been integrated with existing gray infrastructure (GrayI) to reduce CSO events. However, there lacks a goal-oriented planning framework for eliminating CSOs at a watershed/sewershed scale. Moreover, existing stormwater simulations based on catchments or other geographic units, do not consider spatial variation within the unit, such as distribution, attribution, ownership, and management of GI. We propose a scenario-based Stormwater Management Planning Support System for CSOs (SMPSS-CSO) to provide a platform for reducing CSO events by coordinating parcel-based installations of GI. We applied the SMPSS-CSO to a sewershed with a single CSO location in Cincinnati, Ohio and developed four scenarios representing increased use of GI (rain barrels, green roofs, porous pavements, and detention basin) based on its cost, difficulty of installation, and property ownership. Runoff quantity, time of concentration, and peak flow rate were simulated using the curve number method. Our analysis shows a 41% reduction in stormwater runoff is necessary to eliminate CSO events for a two-year rainfall, required 97.25% of private and 27.59% of public parcels to install GI. GI alone cannot eliminate CSO events in this sewershed and must be incorporated with additional GrayI (e.g., storage tanks, pipes). The SMPSS-CSO has the potential for including multiple stakeholders' preferences and concerns in the searching for preferable scenarios.

The paper provides an investigation and understanding of the significance of various wastewater flows on microplastics retainment and emission to the environment. WWTPs and sewer overflows as an important pathway of microplastics to the environment are assessed by considering the removal of microplastics in WWTPs with different treatment processes and several sewer overflow types and their contribution to microplastic loads to recipients. On the example of the Baltic Sea basin, presented results indicate a considerable discharge of microplastic from WWTPs despite the relatively good overall removal efficiency. Results show that the discharge of microplastics from sewer overflows can be in the same magnitude as from treated wastewater although the total flow is much lower than that of treated wastewater. Sewer overflow events frequently occur and are expected to increase due to climate change and urbanization, unless infrastructure is adapted. At the same time, sewer overflows are often neglected in conventional wastewater handling.

The paper provides an investigation and understanding of the significance of various wastewater flows on microplastics retainment and emission to the environment. WWTPs and sewer overflows as an important pathway of microplastics to the environment are assessed by considering the removal of microplastics in WWTPs with different treatment processes and several sewer overflow types and their contribution to microplastic loads to recipients. On the example of the Baltic Sea basin, presented results indicate a considerable discharge of microplastic from WWTPs despite the relatively good overall removal efficiency. Results show that the discharge of microplastics from sewer overflows can be in the same magnitude as from treated wastewater although the total flow is much lower than that of treated wastewater. Sewer overflow events frequently occur and are expected to increase due to climate change and urbanization, unless infrastructure is adapted. At the same time, sewer overflows are often neglected in conventional wastewater handling.

After an increase in capital investment in UK sewers to reduce hydraulic capacity problems, the proportion of sewer flooding incidents now linked to blockages has increased. It is clear that if sewer operators are to continue to reduce flooding incidents, then better blockage management is now required. Sewer blockage formation is poorly understood, blockages are intermittent and occur in a number of circumstances. This paper reports on the development of low cost acoustic instrumentation that can identify the location of a pipe blockage and then estimate the local head loss as a result of the presence of a blockage. A set of experiments were carried out in two full scale laboratory pipes. The pipes' condition was altered by inserting blockages of different sizes. Acoustic data was recorded and presented in terms of the acoustic energy reflected from the partially blocked pipe. The results of this study show that the total reflected acoustic energy correlates with the measured head loss. A new empirical relation between the reflected acoustic energy and head loss due to a blockage is derived. This knowledge can then be used to estimate the reduction in flow capacity resulting from a blockage based on a single remote measurement.

The Totten Mine project specified two parallel main return air fans located on-surface equipped with baffle silencers designed to attenuate the sound levels from the fan outlets. In late 2014, an acoustical study determined that the return air fans were responsible for a series of noise disturbances in a community situated approximately 9 km to the northeast. The results of the acoustical study also indicated that the silencers were significantly underperforming due to clogging with a combination of particulate and moisture drawn from the underground mine. During 2015 and the beginning of 2016, Totten Mine implemented a cleaning procedure to mitigate the underperformance of the silencers. Unfortunately, noise monitoring of the cleaning procedures indicated diminishing results over time. As a result, a temporary solution was identified and implemented in Q3 and Q4 of 2016 to allow adequate time for engineering and defining of a long-term solution. The proposed temporary solution, however, had the potential to become the permanent solution, subject to an evaluation of performance. This paper presents the results of the temporary solution evaluation, when compared to the baseline cleaning procedure. The temporary solution is then compared to the proposed alternatives that were to be part of a feasibility study for both capital (CAPEX) and operational (OPEX) cost evaluation. The resulting long-term solution to manage noise issues on mine return air systems, similar to the Totten experience, is also presented and discussed.

Sanitary sewage yields the basic and most important pollution load diverted to receiving waters during combined sewer overflow (CSO). To reduce overflow pollution loads, it is proposed to store waste water in sanitary sewage detention tanks (SST). For high efficiency those SSTs should be filled and emptied by pumps or gates, operated by control devices. Control strategies have to be worked out depending on different situations and parameters (catchment, rain and flow characteristics).

For mixed combined/separate sewer systems it is proposed, in times of combined sewage overflows (CSO), to store sanitary sewage at the inlet point to the combined system. Thereby, sanitary sewage (with high strength) is kept in the system for further treatment after the storm whereas less-polluted CSO are diverted to the receiving water. By using data of an existing catchment different scenarios are evaluated and the potential benefit of sanitary sewage detention is quantified. This approach is compared to current German CSO regulations. It is more effective than conventional CSO detention if more than 60 % of the population upstream of the CSO diversion are served by a separate system. A key problem of this concept is the control strategy that determines when to activate and empty the storage tanks. A number of criteria are compared. Considerations are also made on operational aspects such as chemical transformations in stored sewage, maximum allowable detention time, and cleansing...

Many studies have analysed and quantified stormwater runoff polluting impact in water bodies. In the meantime municipalities encourage the use of stormwater control measures (SCM) to reduce waterflows and pollutant contamination. In this context, the Micromegas project aims at i) determining how to evaluate the efficiency of SCMs regarding micropollutant (MP) removal and ii) comparing the efficiency of centralized "end of pipes" SCMs versus source control systems. Their efficiency is determined through in-situ sampling, the quantification of 54 MP and the comparison of concentration loads at the outlet of a retention basin (centralized system) and three source control systems (a swale, a trench and a porous pavement) with respectively water from the supplying pipe network and the outlet of a similar impervious asphalted site. This article presents our first results regarding these four sites efficiency as well as the monitoring and sampling procedures and the comparison methodology.

This document has been prepared for the European Commission howe ver it re flects the vie ws only of the authors, and the Commission cannot be held re sponsible for any use which m ay be made of the information contained therein. More information on the European Union is a vailable on the Internet ( uro pa.eu).

INTRODUCTION Combined sewer overflows (CSOs) have been recognized as a dangerous pollutant source for receiving water bodies, and CSO treatment is hence very important to promote a sustainable development. Constructed wetlands (CWs) are starting to be considered as a viable and eco-sustainable technology to treat CSOs (Meyer et al., 2013). However, CSO-CW provides other ecological services beside to water treatment: (i) urban runoff management, (ii) biodiversity increase, (iii) social services (e.g., recreation). Here we have developed a mathematical model of a real case study to highlight the functioning of CSO-CW as also a flood mitigation system, which promotes an urban runoff management from a post-development (high peak, short duration) back again to a pre-development (low peak, high duration) hydrograph influent to the river (Fletcher et al., 2013). METHODS The experimental case study is located in Gorla Maggiore, Italy (46°N, 9°E). The CSO-CW is composed of: (i) grid and sedi...

Combined sewer systems are designed to transport stormwater surface run off in addition to the dry weather flows up to defined limits. In most European countries, hydraulic loads greater than the design flow are discharged directly into receiving water bodies, with minimal treatment (screening, sedimentation), or with no treatment at all. One feasible solution to prevent receiving waters from strong negative impacts seems to be the application of vertical flow constructed wetlands. In Germany, first attempts to use this ecological technology were recognized in early 1990s. Since then, further development continued until a high level of treatment performance was reached. During recent years the national "state-of-the-art" (defined in 2005) was adapted in other European countries, including France and Italy. Against the background of differing national requirements in combined sewer system design, substantial developmental steps were taken. The use of

Hydrographs and pollutographs of sevenwell-known PPCPs have been characterized in a combined sewer in dry and wet weather. ► Event maximum and mean concentrations were higher than daily dry weather ones in several analyzed PPCPs. ► A significant mobilization of PPCPs during rain events has been observed. ► In general, dry weather flow concentrations are similar to extensive literature review. ► A positive relationship between removal degree in WWTP and wet weather mobilization has been observed.

The main topic of the research project presented here in part is the determination of pollutant loads during combined sewer overflow events in several experimental catchments in Spain that were determined to obtain a pollution pattern which may be applied to other catchments in Spain or an order of magnitude of pollution loads in Spanish catchments. The existence or nonexistence of a first-flush is also examined. Five catchments were monitored in five Spanish cities, and both hydraulic parameters and pollutant amounts were measured in dry conditions and during rainfall events. From the data obtained, some parameters were extracted for each catchment and an order of magnitude of the pollution amounts was proposed for Spanish catchments, in terms of event mean concentration (EMC) and maximum concentrations, since the moderate differences between catchments permit an estimation of a mean value.

A detailed research project is set up to validate a vortex separator overflow construction. In this vortex separator, collected sewer water enters radially from the sewer pipe in a cylindrical inner reservoir. The passage flow to the treatment plant is situated in the bottom centre, while the overflow passes a radial weir into an outer shell reservoir. In a laboratory model the removal efficiency of this overflow structure is identified for several hydrodynamic flow operation modes by recording sediment redistribution over the structure. As a result of these series of experiments on a model of a vortex separator overflow, the efficiency of this kind of construction is identified as a function of both hydrodynamic parameters and lay-out features. Doing so, the vortex separator is introduced as an alternative overflow construction to control and manage combined sewer overflow (CSO)-events, leading to a less negative operation impact of combined sewer systems on the receiving waters.

Combined sewer overflow (CSO) structures are constructed to effectively discharge excess water during heavy rainfall, to protect the urban drainage system from hydraulic overload. Consequently, most CSO structures are not constructed according to basic hydraulic principles for ideal measurement weirs. It can, therefore, be a challenge to quantify the discharges from CSOs. Quantification of CSO discharges are important in relation to the increased environmental awareness of the receiving water bodies. Furthermore, CSO discharge quantification is essential for closing the rainfall-runoff mass-balance in combined sewer catchments. A closed mass-balance is an advantage for calibration of all urban drainage models based on mass-balance principles. This study presents three different software sensor concepts based on local water level sensors, which can be used to estimate CSO discharge volumes from hydraulic complex CSO structures. The three concepts were tested and verified under real practical conditions. All three concepts were accurate when compared to electromagnetic flow measurements.

This study deals with the evaluation of the hydrologic metabolism of the Greater Moncton (GM) region, from a sustainable and integrated development of water resources perspective. The hydrological metabolism approach involves the quantification of water inputs and outputs. Therefore, a water balance for the region was carried out for the period 1984 to 2004. An average annual water volume was determined for each of the nine components used within the balance equation. Water inputs calculated for the system included: 263 × 10 6 m 3 /yr for total precipitation and 17.7 × 10 6 m 3 /yr for potable water produced at the water treatment plant. For system outputs, values were: 99.9 × 10 6 m 3 /yr for evapotranspiration, 110 × 10 6 m 3 /yr for infiltration, 22.7 × 10 6 m 3 /yr for wastewater at the sewage plant outlet (exfiltration 6.1 × 10 6 m 3 /yr), 37.7 × 10 6 m 3 /yr of the precipitation amount drained by the storm sewer network, 1.05 × 10 6 m 3 /yr for overflow and 3.55 × 10 6 m 3 /yr for potable water losses in the water distribution system. These input/output results were validated through an analysis of the water system's calculated losses (20%) in relation to values estimated by the GM municipal authorities (between 10% and 20%). This study concluded that the approach and information provided offer many potential benefits that could lead to sustainable and integrated management of water resources in the GM region. It also provides an approach for municipal authorities within the GM region that could be incorporated as a tool to support their decision-making process. In addition, the information presented in this study could form the basis of an educational program. Résumé : Cette étude traite de l'évaluation du métabolisme hydrologique urbain de la région du Grand Moncton selon une perspective de développement durable et intégré des ressources en eau. L'approche du métabolisme hydrologique consiste à quantifier les intrants et les extrants d'eau à travers un système. Le bilan hydrique de la région a été réalisé à partir de l'analyse du cycle hydrologique de cette dernière. Un volume moyen d'eau, évalué pour la période allant de 1984 à 2004, a été déterminé pour chacun des neuf paramètres de l'équation de ce bilan. Les valeurs calculées sont, pour les intrants au système : 263 × 10 6 m 3 /a pour les précipitations totales et 17,7 × 10 6 m 3 /a pour l'eau potable produite à la station de traitement de l'eau. En ce qui concerne les extrants au système, ces valeurs calculées sont : 99,9 × 10 6 m 3 /a pour l'évapotranspiration et 110 × 10 6 m 3 /a pour l'infiltration, 22,7 × 10 6 m 3 /a pour les eaux usées à la sortie Canadian Water Resources Journal/Revue canadienne des ressources hydriques © 2009 Canadian Water Resources Association de la station d'épuration (exfiltration 6.1 × 10 6 m 3 /a), 37,7 × 10 6 m 3 /a pour les précipitations drainées par le réseau d'égouts pluviaux, 1,05 × 10 6 m 3 /a pour les débordements et 3,55 × 10 6 m 3 /a pour les pertes en eau potable dans le réseau d'aqueduc. Ces résultats ont été validés par la concordance entre la valeur calculée de pertes dans le réseau d'aqueduc (20 %) et celle estimée par les autorités municipales du GM (entre 10 % et 20 %). Cette étude conclut que l'approche et l'information fournies offrent des bénéfices potentiels significatifs qui permettraient d'atteindre une gestion durable et intégrée des ressources en eau dans la région du Grand Moncton. Elle souligne d'autre part qu'un certain nombre de défis devront être surmontés par les autorités municipales s'ils l'incorporaient dans leurs processus de prise de décisions. De plus, l'information recueillie dans cette étude pourrait servir à l'élaboration de projet de sensibilisation auprès de la population du Grand Moncton.

The design of industrial sewer design system is a large scale optimization problem, involving many complex calculations. Recently, this problem has been compounded by the evident need to embrace more than a single measure of performance into the design process, since by nature multi-objective optimization methods require more iteration .these problem properties have motivated several prier studies to use computational software's because these software's have been shown to obtain higher quality solutions for large sewer system design problems. They do not require much time in order to achieving a satisfactory solution. Hence the use of design software's for design of an industrial sewer system could be a remedy to this problem. These specific software's are capable of achieving a satisfactory level of performance with limited number of function evaluations represent a valuable alternative. A sewer system is an underground conduit or drain though which sewerage is conveyed to the point of discharge or disposal. many design & construction factors need to be considered before sewer design can be completed .factors such as design period , peak ,average , minimum flows ,sewer slopes ,minimum and maximum velocities ,design equation, sewer material ,joints and connection, appurtenance and sewer installation etc. are all important in developing sewer design. In this study sewer cad software is being used for designing problem of a real medium size sewer system in Chopanki ,an industrial area in district Alwar (Rajasthan ).Results obtained suggest that the use of sewer CAD software could be successfully extended to the efficient design of large scale sewer systems.

The design of sewer system design is a large scale optimization problem, involving many complex calculations. Recently, this problem has been compounded by the evident need to embrace more than a single measure of performance into the design process, since by nature multi-objective optimization methods require more iteration .these problem properties have motivated several prier studies to use computational software's because these software's have been shown to obtain higher quality solutions for large sewer system design problems. They do not require much time in order to achieving a satisfactory solution. Hence the use of design software's for design of an Sewer system could be a remedy to this problem. These specific software's are capable of achieving a satisfactory level of performance with limited number of function evaluations represent a valuable alternative. A sewer system is an underground conduit or drain though which sewerage is conveyed to the point of discharge or disposal. many design & construction factors need to be considered before sewer design can be completed .factors such as design period , peak ,average , minimum flows ,sewer slopes ,minimum and maximum velocities ,design equation, sewer material ,joints and connection, appurtenance and sewer installation etc. are all important in developing sewer design. In this study sewer cad software is being used for designing problem of a real medium size sewer system for kota city Rajasthan .Results obtained suggest that the use of sewer CAD software could be successfully extended to the efficient design of large scale sewer systems.

The overall aim of the ScorePP project is to develop comprehensive and appropriate source control strategies that authorities, cities, water utilities and the chemical industry can employ to reduce emissions of priority pollutants (PPs) from urban areas into the receiving water environment. Focus is on the 33 priority and priority hazardous substances and substance groups identified in the European Water Framework Directive. However, this list may be expanded to include emerging pollutants or reduced if appropriate model compounds can ...

The fecal coliform footprint in a Lake Michigan urban coastal area was studied using field sampling and modeling. Testing for fecal indicator bacteria at large spatial scales is not feasible after rain events; therefore it is desirable to develop a predictive model. A whole-lake model/nested model provided sufficient spatial and temporal resolution, simulated the appropriate transport mechanisms, and was verified against measurements. The major limitation of modeling watershed inputs is that there is no feasible continuous measurement of bacteria, which was addressed by developing a robust correlation between flow and bacteria concentrations. Field data and model predictions verified that most of the mixing between river and lake water occurs inside the harbor breakwater. Measurements and model results showed that the footprint can extend up to 8 km into the lake during sewer overflow events, depending on the meteorology that drives the interaction between tributary loads, whole-lake, and local circulation.

Aging wastewater collection and treatment systems have not received as much attention as other forms of infrastructure, even though they are vital to public health, economic growth, and environmental quality. Inflow and infiltration (I&I) are among potentially widespread problems facing central sewage collection and treatment systems, posing risks of sanitary system overflows (SSOs), system degradation, and water quality impairment, but remain poorly quantified. Whole-system analyses of I&I were conducted by regression analyses of system flow responses to rainfall and temperature for 93 wastewater treatment plants in 23 counties in eastern North Carolina, USA, a coastal plain region with high water tables and generally higher rainfalls than the continental interior. Statistically significant flow responses to rainfall were found in 92% of these systems, with 2-year average I&I values exceeding 10% of rainless system flow in over 40% of them. The effects of rainfall, which can be intense in this coastal region, have region-wide implications for sewer system performance and environmental management. The positive association between rainfall and excessive I&I parallels the effects of storm water runoff on water quality in that excessive I&I can also drive SSOs, thus confounding water quality protection efforts.

Wastewater reclamation is becoming an important alternative for sustainable water resources management and building climate change resiliency in many regions around the world. This research investigated the polishing of secondary effluents and combined sewer overflows (CSOs) by a laboratory-scale soil aquifer treatment considering local soils and wastewater characteristics of southwestern Ontario. Results show that high permeability soils of southwestern Ontario, have the ability to polish secondary effluents in terms of dissolved organic carbon, Escherichia coli, and total coliforms. Regarding the simulated CSOs, low to moderate improvements of wastewater quality were observed. Denitrification of secondary effluents improved significantly by the addition of readily available organic matter, which supports the importance of protecting recharge wetlands for groundwater quality protection. Soil aquifer treatment in southwestern Ontario is a feasible alternative for the recharge of non...

including impacts on energy consumption, property value, urban heat island effect, community health, and global climate change. Green infrastructure's benefits accrue across varied geographical scales. Previous studies have surveyed economic benefits literature . Numerous studies define benefits specific to particular practices or impacts. And others summarize benefits of one or several practices in a single locale (e.g., Stratus Consulting, 2009). The difficulty lies in integrating valuation of these multiple benefits, in quantifying benefits that may not be easily monetized, and in bringing recognition of these values into infrastructure investment decisions by developers, communities, and agencies. This paper reviews current methods, tools and case studies of valuation of the economic and social benefits produced by green infrastructure practices, particularly as they are applied in urban settings. It begins to define a framework for assessing the economic benefits of LID practices on site and community scales. Analysis begins by defining benefits that accrue with a set of common GI practices: tree planting, infiltration practices, permeable pavement, water harvesting, and green roofs. Each practice suggests input units as the basis for benefit calculations, explores variables that affect the accumulation of benefits, and scales at which the benefit occurs. We explore the relationship between input units of green infrastructure practice with resource units representing the value of individual benefits. Finally, we discuss how calculation of site scale benefits can be aggregated at larger scales and between practices. Although some of the benefit calculations discussed vary according to regional or local cost factors and site-dependent impact measurements, the ultimate aim is to allow assessment of GI benefits that is flexible in accounting for such local and regional differences. We also recognize that cost-effective infrastructure decisions require comparing the benefits evaluated here with costs and performance related to both GI and conventional practices. GI practices could conceivably incur costs that do not occur with conventional practices, either in construction or maintenance. A full economic analysis including costs and benefits is beyond the scope of this paper, but the research presented here focuses on beginning to clarify the benefits side of the equation to improve future infrastructure investment decisions. Trees provide many ecosystem services which are detailed below. For the purposes of this paper, most of the benefits from urban forests will be assessed on a per tree basis. When considering trees as an infrastructure method at larger scales (e.g. municipal or watershed planning), percent canopy cover may be a more meaningful measure. Finally, for some services provided, the percentage of a given land area that is vegetated can also be a useful unit of measurement.

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As part of the revised EU Bathing Water Directive, there is scope to discount bathing water quality samples which show poor water quality if poor water quality is predicted and the public forewarned. The Cloud to Coast (C2C) project is developing a model to allow prediction of faecal indicator organism (FIO) concentrations in bathing waters. One of the C2C sub-models is investigating FIO loads from urban catchments. As part of this urban sub-model, the hypothesis of whether FIO loads exhibit a first foul flush in wet weather events is being investigated. This paper presents typical data from two combined sewer overflow outfalls, and based on the data collected suggests there is no first foul flush of FIOs. However sampling took place over a wet summer and hence antecedent dry weather periods (ADWP) were short, and previous research has shown ADWP to be a factor in the first foul flush of pollutants.

Dealing with stormwater runoff from water quantity and water quality aspects has always been a category of necessary municipal infrastructure. Bioretention Cells (BRCs) are new features of this infrastructure. A BRC is a basin in the ground that consists of a surface bowl to initially capture runoff which can filter through a permeable media. The primary objective of BRCs is for water quality treatment but their contribution to water quantity control objectives of an overall stormwater design for a medium density subdivision is not fully understood. From 2011 to 2017, a low-density residential subdivision in the greater Toronto Area, Mosaik Glenway, was constructed as a pilot study. Its stormwater system includes three BRCs. The objective of this research is to use the results of monitoring and computer modelling of the Mosaik Glenway subdivision to help understand the contribution that BRCs can make to quantity control in stormwater management (SWM). Modelling results presented in this thesis demonstrate that BRCs can help mitigate the loss of infiltration due to urbanisation. Under favourable soil conditions, they may have the potential to fully mitigate the loss of infiltration due to urbanization. BRCs are also capable of reducing the amount of quantity storage normally required by traditional SWM facilities for a wide range of precipitation events, including large storm events, even if they are constructed in less-than-favourable soil conditions. Moreover, BRCs also have opportunities to reduce overall stormwater management infrastructure costs.

A shallow Periphyton Culture on the Roof of a Large Flat roofed building has significant advantages over the DOE Cool roof in Semi Tropical and Tropical climates with fresh surface water, like Florida USA.  Advantages include Carbon Foot Print reduction, Air Conditioning energy reduction of 20-40%, restoring wetland filtration (nutrient removal) from wetlands lost to pre regulation development, reduction of Urban Heat Island Effect.  Architects and builders have been slow to adopt.

This chapter describes the capabilities and features of the recently developed Illinois transient model (ITM) for simulating the flow dynamics (transient and non-transient conditions) in combined storm sewer systems, ranging from dry bed flows, to gravity flows, to partly gravity-partly surcharged flows (mixed flows), to fully pressurized flows (water hammer flows). ITM, which was originally developed at the University of Illinois at Urbana-Champaign, is a finite volume (FV) model that can handle complex boundary conditions such as drop shafts, reservoirs, closing and opening of gates as a function of time, and junctions with any number of connecting pipes and any types of horizontal and vertical alignment. ITM is open source code that is in constant development and its releases are made available on a regular basis. In the current version of ITM (v. 1.3, September 2010), the free surface region is modeled using the one dimensional (1-D) Saint-Venant equations. The pressurized region is modeled using the 1-D compressible water hammer equations. Open channel-pressurized flow (mixed flow) interfaces are modeled by enforcing mass, momentum and energy relations across the interfaces together with Riemann solvers at the sides of mixed flow interfaces. This version of ITM is referred to as the two equation model. The current version of ITM is superior to other models of its kind because it is robust, can simulate mixed flows (simultaneous occurrence of free surface and pressurized flows) when using actual pressure wave celerities (~1 000 m/s), and because no Preissmann slot assumption is made to simulate pressurized flows (water hammer flows). ITM has been applied to

Pour établir des plans d'investissements, le plus grand problème est la comparaison plus ou moins objective des projets qui sont souvent d'une nature complètement différente. LIBRA est un instrument qui est développé pour évaluer des projets d'assainissement concernant leur impact. Cet instrument est basé sur le comportement hydrologique des systèmes d'assainissement (unitaires) en utilisant les résultats des simulations continus et à long terme avec un logiciel simplifié. LIBRA utilise l'information et les mesures disponibles et des paramètres faciles à estimer. Tous les résultats sont exprimés dans la même unité finale. L'utilisation pratique de LIBRA pendant deux années de plans d'investissements prouve qu'il est possible de comparer l'impact de projets complètement différents d'une manière standardisée et d'établir des classifications réalistes comme aide à la décision qui soutient la stratégie de l'agence environnementale.

Pour établir des plans d'investissements, le plus grand problème est la comparaison plus ou moins objective des projets qui sont souvent d'une nature complètement différente. LIBRA est un instrument qui est développé pour évaluer des projets d'assainissement concernant leur impact. Cet instrument est basé sur le comportement hydrologique des systèmes d'assainissement (unitaires) en utilisant les résultats des simulations continus et à long terme avec un logiciel simplifié. LIBRA utilise l'information et les mesures disponibles et des paramètres faciles à estimer. Tous les résultats sont exprimés dans la même unité finale. L'utilisation pratique de LIBRA pendant deux années de plans d'investissements prouve qu'il est possible de comparer l'impact de projets complètement différents d'une manière standardisée et d'établir des classifications réalistes comme aide à la décision qui soutient la stratégie de l'agence environnementale.

The research on Combined Sewer Overflows (CSO's) in Flanders is focussed on the one hand on the design and optimisation of ancillary structures at CSO's and on the other hand on the prediction of the impact of CSO emissions. For the assessment of the CSO emissions, conceptual models using continuous long term simulations are preferred, because the event based approach using synthetic storms does not lead to accurate probability estimation of the emissions. Very important in this approach are physically based modelling, a statistically based methodology and an evolution to integrated and probabilistic modelling. However, the application of these methodologies and technologies in practice is still in a preliminary phase.

Wastewater infrastructures play an indispensable role in society's functioning, human production activities, and sanitation safety. However, climate change has posed a serious threat to wastewater infrastructures. To date, a comprehensive summary with rigorous evidence evaluation for the impact of climate change on wastewater infrastructure is lacking. We conducted a systematic review for scientific literature, grey literature, and news. In total, 61,649 documents were retrieved, and 96 of them were deemed relevant and subjected to detailed analysis. We developed a typological adaptation strategy for city-level decision-making for cities in all-income contexts to cope with climate change for wastewater structures. 84% and 60% of present studies focused on the higherincome countries and sewer systems, respectively. Overflow, breakage, and corrosion were the primary challenge for sewer systems, while inundation and fluctuation of treatment performance were the major issues for wastewater treatment plants. In order to adapt to the climate change impact, typological adaptation strategy was developed to provide a simple guideline to rapidly select the adaptation measures for vulnerable wastewater facilities for cities with various income levels. Future studies are encouraged to focus more on the model-related improvement/prediction, the impact of climate change on other wastewater facilities besides sewers, and countries with low or lower-middle incomes. This review provided insight to comprehensively understand the climate change impact on wastewater facilities and facilitate the policymaking in coping with climate change.

Discharges of untreated wastewater from combined sewer overflows (CSOs) can affect hydraulic stress and have significant environmental impacts on receiving water bodies. Common flow rate and water level sensors for monitoring of CSO events are expensive in terms of investment costs, installation, operation and maintenance. This paper presents a novel surrogate method to detect CSO events by using two low-cost temperature sensors. The novelty is the experimental setup for installation of temperature sensors in CSO structures and an algorithm developed to automatically calculate the duration of CSO events considering the response time of the system. The occurrence and duration of CSO events is computed based on the convergence of the two temperature signals. The method was tested under field conditions in a CSO structure, and the results were compared to the information gathered from a parallel installed flow sensor. The application of two temperature sensors installed inside a CSO structure was proven to be robust and accurate for the automatic detection of the occurrence and duration of CSO events. Within the 7-month test phase, 100% of the 20 CSO events could be detected without false detections. The accuracy of detecting the start and end of the CSO events was 2 min in comparison to the flow sensor.