Showing papers in "Urban Water Journal in 2010"
TL;DR: A comprehensive review of the leakage management related methods developed so far can be broadly classified as follows: (1) leakage assessment methods which are focusing on quantifying the amount of water lost; (2) leakage detection methods that are primarily concerned with the detection of leakage hotspots and (3) leakage control models which are focused on the effective control of current and future leakage levels.
Abstract: Leakage in water distribution systems is an important issue which is affecting water companies and their customers worldwide. It is therefore no surprise that it has attracted a lot of attention by both practitioners and researchers over the past years. Most of the leakage management related methods developed so far can be broadly classified as follows: (1) leakage assessment methods which are focusing on quantifying the amount of water lost; (2) leakage detection methods which are primarily concerned with the detection of leakage hotspots and (3) leakage control models which are focused on the effective control of current and future leakage levels. This paper provides a comprehensive review of the above methods with the objective to identify the current state-of-the-art in the field and to then make recommendations for future work. The review ends with the main conclusion that despite all the advancements made in the past, there is still a lot of scope and need for further work, especially in area of rea...
577 citations
TL;DR: In this paper, different statistical models used in predicting the structural deterioration of urban drainage pipes are presented, along with their data requirements and applications in infrastructure asset management, and a discussion is also made on the issues and challenges related to the developments of these models.
Abstract: Wastewater and stormwater collection and conveyance systems are undergoing aging and deterioration, leaving cities vulnerable to their ill-effects, e.g. collapse and flooding. To avoid such problems, utilities began implementing some sort of urban drainage infrastructure asset management systems. One of the key components of these systems is the ability to predict the infrastructure's future performance. This paper discusses the different statistical models used in predicting the structural deterioration of urban drainage pipes. The concepts behind the models, along with their data requirements and applications in infrastructure asset management, are presented. Finally, a discussion is also made on the issues and challenges related to the developments of these models.
137 citations
TL;DR: In this article, the authors present a methodology for assessing an isolation valve system and the portions of a water distribution network (segments) directly isolated by valve closure, which is not always straightforward to achieve as the valve system is not normally designed to isolate each pipe separately (i.e. having two valves at the end of each pipe).
Abstract: This paper presents a novel methodology for assessing an isolation valve system and the portions of a water distribution network (segments) directly isolated by valve closure. Planned (e.g. regular maintenance) and unplanned interruptions (e.g. pipe burst) occur regularly in water distribution networks, making it necessary to isolate pipes. To isolate a pipe in the network, it is necessary to close a subset of valves which directly separate a small portion of the network, i.e., causing minimum possible disruption. This is not always straightforward to achieve as the valve system is not normally designed to isolate each pipe separately (i.e. having two valves at the end of each pipe). Therefore, for management purposes, it is important to identify the association between each subset of valves and the segments directly isolated by closing them. Furthermore, it is also important to improve the design of the isolation valve system in order to increase network reliability. Thus, this paper describes an algorit...
133 citations
TL;DR: In this article, the authors investigated the effect of water pressure in a pipe on the rate of leakage from leak openings in the pipe and found that pipe stresses are significantly affected by a leak opening, and can easily exceed the material's yield strength in the vicinity of the opening.
Abstract: The effect of water pressure in a pipe on the rate of leakage from leak openings in the pipe is one of the main factors influencing leakage that is still not understood sufficiently. In this study, the behaviours of different types of leak openings (round holes and longitudinal and circumferential cracks) on pressurized pipes were investigated for different pipe materials (uPVC, steel, cast iron and asbestos cement) using finite element analysis. Linear elastic behaviour was assumed. The study found that (1) pipe stresses are significantly affected by a leak opening, and can easily exceed the material's yield strength in the vicinity of the opening; (2) round holes show the smallest expansion with pressure, followed by circumferential cracks and then longitudinal cracks; (3) the areas of all leak openings increase linearly with pressure; (4) longitudinal pipe stresses affect the behaviours of round holes and circumferential cracks, but not that of longitudinal cracks; and (5) the effect of pressure on a l...
122 citations
TL;DR: In this paper, the existing self-cleansing design criteria for sewers based on minimum velocity and minimum bed shear stress have been reviewed and based on several laboratory experiments, the study then develops non-deposition criteria for non-cohesive sediment in uniform flow.
Abstract: In this study, the existing self-cleansing design criteria for sewers based on minimum velocity and minimum bed shear stress have been reviewed. Based on several laboratory experiments, the study then develops non-deposition criteria for non-cohesive sediment in uniform flow. The developed criteria take into account geometry of flow sections, hydraulic and sediment properties based upon three dimensionless parameters, namely, the densimetric Froude number, the volumetric sediment concentration and the relative grain size. The proposed criteria provide improved estimates of self-cleansing minimum velocities compared to the traditional one-parameter design criteria and agree well with the well-known existing design criteria, namely, Macke's formula for suspended load and May's formula for bed load. The present study therefore contributes new non-deposition design criteria for sewers with part-full flow in the range of the experiment conducted and yet which are simple for practical applications. Further rese...
101 citations
TL;DR: In this paper, the degree and extent of two types of drainage materials, concrete and PVC, on urban water chemistry was examined and three types of water were then circulated through a concrete pipe or PVC pipe for 100min and measured for a range of water chemical attributes.
Abstract: Waterways contain a chemical signature of catchment land use, climate and geology. This is increasingly being influenced by the urban landscape and particularly the composition of materials and activities that occur on impervious surfaces. This paper examines the degree and extent of two types of drainage materials, concrete and PVC, on urban water chemistry. This study found that water collected from a zinc and slate/tile roof and stored in a plastic rain tank (roof water) was acidic (pH 4.79) and had low bicarbonate concentrations (0.5 mg/l), water from an undeveloped catchment (reference creek) was mildly acidic (pH 5.5) with bicarbonate concentrations of 1.7 mg/l while water from a stream draining a residential catchment (urban creek) was mildly alkaline (pH 7.35) with bicarbonate concentrations of 36.3mg/l. The three types of water were then circulated through a concrete pipe or PVC pipe for 100 min and measured for a range of water chemical attributes. Roof water and water from the reference creek r...
77 citations
TL;DR: In this article, the authors present a method to identify the optimal locations of pressure sensor instruments for the detection of leak/burst events and the results of a set of field trials conducted to evaluate the approach.
Abstract: This paper presents a method to identify ‘optimal’ locations of pressure sensor instruments for the detection of leak/burst events and the results of a set of field trials conducted to evaluate the approach. The identification method is based on complete enumeration studies using hydraulic model simulations of a wide range of burst events and evaluating the response to each event at all possible monitoring points. The field trials simulated leak/burst events through the opening of fire hydrants within a selected District Metered Area (DMA), five different hydrants were opened systematically in the DMA to simulate different leak/burst events. By installing pressure instrumentation at different locations in the DMA, an understanding of how accurately the model methodology can determine sensitivity of instrument location can be obtained. Prior to and during the hydrant openings pressure data was collected at eight different instrument locations within the DMA. These pressure instruments were installed to cov...
72 citations
TL;DR: A numerical model used for evaluating this complex process as well as the application of model to an Italian case study are discussed, which agreed with calibration data and provided interesting insights into the network filling process.
Abstract: In many countries, private tanks are acquired by users to reduce their vulnerability to intermittent supply. The presence of these local reservoirs modifies the user demand pattern and usually increases user water demand at the beginning of the service period depending on the tank filling process. This practice is thus responsible for the inequality that occurs among users: those located in advantaged positions of the network are able to obtain water resources soon after the service period begins, while disadvantaged users have to wait much longer, after the network is full. This dynamic process requires the development of ad hoc models in order to obtain reliable results. This paper discusses a numerical model used for evaluating this complex process as well as the application of model to an Italian case study. The model agreed with calibration data and provided interesting insights into the network filling process.
72 citations
TL;DR: In this paper, a review of the main pollutants in road runoff is presented, and the importance of the factors affecting road runoff quality, the main of which are traffic, rainfall, local conditions (climate and land use) and highway characteristics.
Abstract: Highway runoff often is a significant non-point pollution source. Though it has been extensively studied there are still open questions regarding the identity and mutual influences of the factors affecting pollutant concentrations in road runoff. This review starts with a description of the main pollutants (heavy metals, refractory organics and suspended matter), then it analyzes interactions existing between them and their fractionation between the particulate and dissolved phases. The third section examines the sources of pollution, being: vehicles which contribute fluid and solid pollutants, roads which contribute suspended solids, and dry and wet atmospheric deposition which is influenced by adjacent land-uses. The last section discusses the importance of the factors affecting road runoff quality, the main of which are traffic, rainfall, local conditions (climate and land use) and highway characteristics. The review reveals that conclusions derived from existing data are often ambiguous and significan...
71 citations
TL;DR: In this paper, a monitoring program was undertaken to assess the effectiveness of a permeable road surface for managing the quantity and quality of stormwater runoff in an urban catchment, where the road surface was installed, and the catchment had the effective imperviousness reduced from 45% prior to reconstruction of the road surfaces to less than 5% after reconstruction.
Abstract: Urban stormwater runoff is a transport medium for many contaminants from anthropogenic sources There are many alternative management strategies available to treat these contaminants One of the technologies suggested for this purpose is the use of permeable pavements to minimise the quantity of surface runoff generated by impervious surfaces within an urban catchment Reported herein are the results of a monitoring program undertaken to assess the effectiveness of permeable road surface for managing the quantity and quality of stormwater runoff It was found that the catchment, where the permeable road surface was installed, had the effective imperviousness reduced from 45% prior to reconstruction of the road surface to less than 5% after reconstruction of the road Furthermore, it was found that the generation of surface runoff from the permeable road surface required a rainfall intensity in excess of 20 mm/h Finally, the quality of the surface runoff was found to be at the lower levels of runoff from
48 citations
TL;DR: In this paper, the authors examined people's views on a number of water issues and their motivation, practices and concerns about greywater reuse for irrigation of around homes and found that about half of the participants reused greywater regularly or at some time during the last few years.
Abstract: We examined people's views on a number of water issues and their motivation, practices and concerns about greywater reuse for irrigation of around homes. Survey participants (275) from different socio-economic background from 125 suburbs in the Western Sydney region, Australia took part in the study. Regardless of their age and gender, when asked which was the most important issue regarding water in their region from a prescribed list, the majority of participants identified water quality as the most important and availability without water restriction as the least important. About half of the participants reused greywater regularly or at some time during the last few years. The cost of plumbing and health risks to people, plants and soil are critical issues for greywater reuse and need attention. For the reusing widely and sustainably, there is a need for easily accessible, user-friendly information packages to create ‘greywater reuse literacy’ in the community.
TL;DR: In this paper, the authors developed a model of community acceptance that was consistent over different scales, source-points, end-uses and users of current and future water supply systems.
Abstract: With the growing need for Australian cities to augment their water supplies, the community has displayed increasing interest in alternative water sources. Public attitudes have ranged from enthusiasm to concern, and in some cases have resulted in the rejection of potential new water supplies. To date, there has been little research that has attempted to examine and understand the basis of community acceptance of a new water supply system. This paper outlines a research program that aimed to develop a model of community acceptance that was consistent over different scales, source-points, end-uses and users of current and future water supply systems. It describes the development of an hypothesised model of community acceptance which incorporated a range of psycho-sociological variables. This then went through a preliminary assessment, followed by testing of the model, and finally a confirmatory stage of research. The program resulted in a robust model that can assist planners and developers in understanding...
TL;DR: In this article, the authors investigated the barriers that exist to deter the implementation of rainwater harvesting into new UK housing and concluded that these barriers are deterring house-builders from installing rain water harvesting systems in new homes.
Abstract: This work investigates the barriers that exist to deter the implementation of rainwater harvesting into new UK housing. A postal questionnaire was sent to a selection of large, medium and small house-builders distributed across the UK. Questions were asked concerning potential barriers to the inclusion of rainwater harvesting in homes separated into five sections; (1) institutional and regulatory gaps, (2) economic and financial constraints, (3) absence of incentives, (4) lack of information and technical knowledge, and (5) house-builder attitudes. The study concludes that although the knowledge of rainwater systems has increased these barriers are deterring house-builders from installing rainwater harvesting systems in new homes. It is further acknowledged that the implementation of rainwater harvesting will continue to be limited whilst these barriers remain and unless resolved, rainwater harvesting's potential to reduce the consumption of potable water in houses will continue to be limited.
TL;DR: The need for efficient water resources management is currently more pressing than ever, considering population growth and increased reliability requirements, under climate change conditions as discussed by the authors, and all water utilities operating in EU countries should develop and implement appropriate water pricing policies that will guarantee the recovery of the full cost of the water being used.
Abstract: The need for efficient water resources management is currently more pressing than ever, considering population growth and increased reliability requirements, under climate change conditions. On average, one-third of the total water abstracted for urban uses is being lost due to leaks and breaks occurring in water distribution networks. This means that significant amounts of water and revenues are being lost, forcing water utilities to consider developing effective water loss and Non-Revenue Water reduction strategies. Additionally, all water utilities operating in EU countries should, by the end of 2010, develop and implement appropriate water pricing policies that will guarantee the recovery of the full cost of the water being used. This strict obligation makes the reduction of water losses an even more urgent goal that the water utilities have to achieve. The first step towards all the above-mentioned goals is to safely evaluate the performance level of the water network. Thus, the IWA Task Forces on Wa...
TL;DR: In this paper, a prioritization approach based on the resilience index and the unitary power concept is proposed to select the most important pipes to replace in order to achieve two main objectives: first, to reduce loss of water due to leakage by decreasing and levelling pressures along the entire network; second, to decrease the dissipated energy in the system, making it more efficient and reliable.
Abstract: This paper presents a new prioritisation approach to the problem of rehabilitation of water distribution systems. It consists in a algorithm that, based on the resilience index and on the unitary power concepts, selects the most important pipes to be replaced in order to achieve two main objectives: first, to reduce loss of water due to leakage by decreasing and levelling pressures along the entire network; second, to reduce the dissipated energy in the system, making it more efficient and reliable. Additionally, the implemented algorithm finds profitable rehabilitation schemes and allows the identification of the appropriate point at which, according to the economic and hydraulic criteria established by the user, the process of replacing pipes should be stopped. This paper includes three case studies – one hypothetical and two real water distribution systems – in which the algorithm was tested. For these networks hydraulically and economically near-optimal rehabilitation schemes were achieved.
TL;DR: In this paper, the authors present the results of an experimental investigation aimed at estimating the water saving obtained by reusing washbasin grey waters for toilet flushing in domestic bathrooms.
Abstract: The paper presents the results of an experimental investigation aimed at estimating the water saving obtained by reusing washbasin grey waters for toilet flushing in domestic bathrooms. Six Italian households characterised by different number of users largely heterogeneous in age, gender, occupation and customs were selected for the experimental campaign. Washbasin and toilet uses for each selected household were monitored recording chronological series of time instants of washbasin tap opening/closure and of toilet flushing operations. On the basis of water balances on a short time scale, acquired data enabled the evaluation of water saving and unused grey water deriving by the adoption of a simple grey water reuse scheme. Specific dimensionless variables were adopted to present the results and to enable their use within the ranges of practical applications.
TL;DR: The first loop of a sustainable urban drainage retrofitting project was completed in Odense over a 6-month period as mentioned in this paper, which involved officials from the City of Odense and Odense Water Ltd., as well as university researchers.
Abstract: The planning and implementation of sustainable urban drainage systems (SUDS) requires intensive collaboration between professions and institutions. To improve the conditions for such practice in Denmark, the first loop of a SUDS-based retrofitting project was completed in Odense over a 6-month period. The project involved officials from the City of Odense and Odense Water Ltd., as well as university researchers. Studies of hydrological, environmental and socio-cultural aspects were developed by disciplinary teams and used to draft integrated solutions for two selected city districts. Albeit sewer surcharge was the initial catalyst, the main driver for the drafted solutions was urban planning. An assessment of the impact 1.5 years after completion indicated that the employed approach is valuable. In Odense, a planning procedure reflecting the loop process has become new practice. The project represents a key reference for the introduction of SUDS in Denmark.
TL;DR: In this article, a sensitivity analysis that uses a network solver to quantify energy savings due to the alteration of three system properties (systemwide water demand, storage tank parameters (maximum water level, diameter, elevation), and pumping stations (horsepower, number of boosters, and their locations) of seven diverse MDWDSs is presented.
Abstract: Municipal Drinking Water Distribution Systems (MDWDSs) consume a significant quantity of energy to transport water, thereby exacerbating greenhouse gas emissions and global climate change. The current study is a sensitivity analysis that uses a network solver to quantify energy savings due to the alteration of three system properties—system-wide water demand, storage tank parameters (maximum water level, diameter, elevation), and pumping stations (horsepower, number of boosters, and their locations) of seven diverse MDWDSs. It was found that a 50% reduction in water demand, main pump horsepower, and booster horsepower resulted in an average energy savings of 47, 41, and 9.5% respectively, for the seven systems analyzed. Other properties examined showed insignificant savings. Even though an individual system analysis is more conclusive, this sensitivity analysis can guide optimization studies to focus on the most sensitive properties.
TL;DR: In this paper, the authors investigated the relationship between spatial patterns of water quality and land occupation in the cities of Cuiaba and Varzea Grande, Mato Grosso state, Brazil, applying Geographic Information System (GIS) techniques and Polynomial Redundancy Analysis.
Abstract: This study investigates the relationship between spatial patterns of water quality and land occupation in the cities of Cuiaba and Varzea Grande, Mato Grosso state, Brazil, applying Geographic Information System (GIS) techniques and Polynomial Redundancy Analysis. The results show a strong relationship between water quality and population density, urbanization rate and regionalized low water runoff. Higher treatment rates improve oxygenation levels, but do not reduce concentrations of total nitrogen, phosphorus and coliforms, indicating inefficiency of the sanitation infrastructure. The presence of more sophisticated treatment systems positively influenced catchment pollution levels. Sub-catchments which impact water quality of the Cuiaba River throughout the year typically deliver loads of mixed origin (impervious surfaces and untreated domestic wastewater). Monitoring stations downstream of the urban reach of the river show a trend of chemical and biological degradation.
TL;DR: In this article, a catchment model SWMM was modified to include on-site flow-control devices, and then linked with models of hydraulic habitat suitability and erosive potential for specific reaches in a study catchment.
Abstract: The catchment model SWMM was modified to include on-site flow-control devices, and then linked with models of hydraulic habitat suitability and erosive potential for specific reaches in a study catchment. Urbanisation decreased the modelled baseflow by up to 33% and reduced the area of suitable hydraulic habitat by 0.5–13.3%, depending on the reach and species. Hypothetical infiltration devices increased the baseflow to pre-development levels, with an associated increase in habitat, but other measures were not effective. Urbanisation increased the erosion potential index by a factor of 1.58–9.32, depending on the reach. Erosion-control ponds decreased the erosion potential to pre-development level in some reaches. Detention tanks reduced the erosion potential significantly, but not to pre-development levels. The poor predictive ability of the models for baseflow compromised the utility of the hydraulic habitat assessment. Predictions of the effects of urbanisation on baseflow habitat should therefore be t...
TL;DR: In this paper, the effect of urban expansion on the qanat fields as well as the difficulties encountered at city construction and water system junctions in the northeastern city of Mashhad, in Iran are explored.
Abstract: The qanat is one of the traditional water supply systems in semi-arid zones. Today, this sustainable system is under threat from various modern phenomena. Urban sprawl is the most salient factor, which poses a major threat to these water systems (qanats). This study endeavors to explore the effect of urban expansion on the qanat fields as well as the difficulties encountered at city construction and water system junctions in the northeastern city of Mashhad, in Iran. Data analysis reveals that rapid urbanization as well as uncontrolled urban expansion has led to the intersection of city construction and qanats; especially during the last few decades. This phenomenon has resulted in the destruction of 88 qanat fields, water shortage in the city of Mashhad, and the substitution of this sustainable and environment-friendly system with alternative unsustainable water systems such as dams and wells.
TL;DR: In this paper, the suitability of wastewater for irrigation, and Cicer arietinum L.cv. avrodhi was used as a test crop, was evaluated in the winter season of 2006-2007 to evaluate its effect together with the basal application of four doses of nitrogen (N0, N15, N30, N45, kg ha−1).
Abstract: The reuse of wastewater in agriculture for irrigation needs specific studies to evaluate its effect on different soils, crops and agro-climatic conditions. This study was therefore conducted to observe the suitability of wastewater for irrigation, and Cicer arietinum L.cv. avrodhi was used as a test crop. The experiment was conducted in the winter season of 2006–2007 to evaluate its effect together with the basal application of four doses of nitrogen (N0, N15, N30, N45, kg ha−1). Wastewater irrigation resulted in the increased growth, photosynthesis and yield of the crop. Lower fertilizer dose of nitrogen @ 15 Kg ha−1 together with wastewater irrigation proved optimum, resulting in greater leaf area, plant fresh weight, dry matter (DM), photosynthetic rate (PN) and stomatal conductance (gs) and leaf N content, number of pods per plant, 100 seed weight and protein content relative to control and even to higher N doses. Thus fertilizer rates could be lowered without reducing yields when using wastewater for...
TL;DR: This paper aims at providing researchers and software developers with a general formulation of the GGA which entails both the adoption of any generic monomial head loss formula and pipe hydraulic resistance dependence on flow regime.
Abstract: The global gradient algorithm (GGA) is the most widely adopted method for steady-state analysis of water distribution networks. It is used to solve the non-linear system of equations describing mass and energy conservation laws. Nonetheless, it has been recently proved that the usually adopted representation of distributed pipe demands as lumped withdrawals at ending nodes causes inconsistent calibration results and pipe head loss errors which could be non negligible in some network conditions. The original GGA has been contextually modified by introducing a correction of pipe hydraulic resistance under the assumptions of a friction factor independent from the flow regime. This paper aims at providing researchers and software developers with a general formulation of the GGA which entails both the adoption of any generic monomial head loss formula and pipe hydraulic resistance dependence on flow regime. The results could be easily extended to other methods of network analysis.
TL;DR: In this paper, the authors analyzed the blockage records of the last 16 years (1991-2006) in the wastewater pipeline network of Oslo and found that older and small diameter pipelines made of concrete, laid almost horizontal to the ground surface are the high priority candidates, and more importantly enables one to compare among the different categories and classes of pipelines.
Abstract: The city of Oslo is evaluating strategies for the selection of appropriate materials for the pipelines and manholes of its wastewater network. The overarching motive is to minimise construction-related failures over the system lifetime and also ensure that it is able to avert flooding events. This paper analyses the blockage records of the last 16 years (1991–2006) in the wastewater pipeline network of Oslo. For the purpose of the analysis, the pipeline stock is categorised on the basis of pipe diameter, material of fabrication, slope and age. Proneness to blockages is studied and attempts are made to correlate the same to the size, material, slope and age. The analyses performed confirm that older and small diameter sewage pipelines made of concrete, laid almost horizontal to the ground surface are the high-priority candidates, and more importantly enables one to compare among the different categories and classes of pipelines.
TL;DR: In this paper, the authors used empirical data from a cross-sectional survey of 505 utility customers in eight urban centres in Uganda to show that customer attitude towards prompt payment, perceived ease or difficulty of paying on time (perceived control), as well as social pressure, strongly influence intentions to pay, which in turn directly affects actual prompt bill payment behavior.
Abstract: Improving revenue collection rates and minimising the levels of ‘bad debts’ is currently a top priority for managers of water utilities in low-income countries. This study used empirical data from a cross-sectional survey of 505 utility customers in eight urban centres in Uganda to show that customer attitude towards prompt payment, perceived ease or difficulty of paying on time (perceived control), as well as social pressure, strongly influence intentions to pay, which in turn directly affects actual prompt bill payment behaviour. The findings also show that gender, income, occupation of the household head and tenure status have statistically significant direct relationships with intentions, but their effects are much smaller compared to the joint influence of attitudes, perceived control and perceived social pressure. Moreover, the effects of gender and occupation are completely mediated by perceived control and social pressure respectively. These results have implications for improving revenue collecti...
TL;DR: In this article, the authors assessed the magnitude of variations in the concentrations of disinfection byproducts, specifically trihalomethanes and haloacetic acids, which occur in two UK water distribution networks of different sizes due to changes in the hydraulic operation of the networks.
Abstract: This study assessed the magnitude of variations in the concentrations of disinfection by-products, specifically trihalomethanes and haloacetic acids, which occur in two UK water distribution networks of different sizes due to changes in the hydraulic operation of the networks. These operational changes included varying the fill levels of water storage tanks and pumping conditions within the network. This was investigated through modelling which combined a conventional distribution network flow model (EPANET) with previously developed models for disinfection by-product formation, and using network information obtained from water company partners. The modelling demonstrated that there is the potential for significant variations in disinfection by-product concentrations, up to a 40% change in some simulations, due to what may be considered routine variability in the hydraulic operation of the network. Smaller networks may be especially susceptible to these variations. These findings may influence how water c...
TL;DR: In this paper, the effects of various design configurations and the operation of detention basins for pollutant removal efficiency were evaluated using a Monte-Carlo simulation approach using a physically based numerical model representing the build-up and wash-off of pollutants from the highway surface.
Abstract: The effects of various design configurations and the operation of detention basins for pollutant removal efficiency is evaluated using a Monte-Carlo simulation approach. A physically based numerical model representing the build-up and wash-off of pollutants from the highway surface has been used to predict storm events pollutographs for dissolved Cu and Zn. The probability of discharging dissolved Cu and Zn from detention basins were assessed using randomly-generated rainfall-runoff events and build-up pollutant concentrations. The simulations were performed by comparing the results of a one-compartment detention basin with a two-compartment design. The simulation results revealed that dividing the detention basin into two compartments and using the first compartment for first flush treatment can substantially reduce the frequency of discharging toxic metals such as Cu and Zn into the receiving waters. With the first flush treatment method, the size of the detention basin can be reduced to half of the con...
TL;DR: In this paper, the authors compared the use of dynamic modeling with the "normative criteria" to evaluate the effects of Combined Sewer Overflows (CSOs) on the Lambro River and the Stream Bevera.
Abstract: Using a case study on the Lambro River and the Stream Bevera, this paper compares the use of dynamic modelling with the “normative criteria” to evaluate the effects of Combined Sewer Overflows (CSOs). The normative criteria is the method currently used in Italy to design first flush water tanks to reduce the pollutant discharges. The dynamic modelling technique compares the natural river conditions and the conditions in the river when a CSO occurs. This study finds that the current law, which is based on an effluent standard approach, can significantly underestimate the size of the CSO storage tanks needed to prevent pollution. An alternative is to change the law to use a stream standard approach and to require the CSO tanks to be sized based on the volume and concentration of the pollutants at the CSO. By using a dynamic model of the river, it was found possible to provide a more accurate estimate of the size of the CSO storage tanks required to prevent pollution. Furthermore the paper finds that without...