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1.
Environ Sci Pollut Res Int ; 27(5): 4630-4639, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31625115

RESUMO

Sustainable drainage systems (SuDS) have emerged as an effective and attractive approach for stormwater management, prevention of water pollution and flood control due to its sustainable, environmentally friendly and cost-effective approaches. One of the SuDS devices widely used to infiltrate, store and treat surface runoff which allows it to recharge groundwater is the pervious paving systems (PPS). Previous studies have demonstrated relatively high pollution removal efficiencies typically ranging from 98.7% for total hydrocarbons to 89% of COD. Although a small number of the studies have assessed the performance characteristics of the PPS system in long-established installations in terms of retention of pollutants, hydrological features, biodegradation of pollutants etc., none has assessed the risk of potential groundwater and soil pollution by pollutants such as metals retained in the PPS materials either as a disposed waste material (in the case of used geotextiles) or during re-use as secondary aggregates. Thus, this study evaluated potential risks associated with the decommissioning and beneficial use of wastes produced during the disassembly of a PPS. The authors believe that this was the first PPS to be addressed in this way. The method involved the determination of leachable concentrations of 14 metals in the PPS samples made up of extracts from the model profile which included the geotextile fibre (G), dust alone (D), aggregates and dust (AD), aggregates alone (AA) and pavement blocks (P) which were analysed and compared with two different groups of regulatory threshold limits. The results showed that the measured concentrations of all the metals were below the appropriate threshold values for irrigation purposes as specified by FAO and USEPA. Furthermore, results all indicated that the dismantled materials were all below EU LFD WAC limits for inert waste, indicating relative ease of disposal and suitability for use as recycled aggregate. This, admittedly limited data, indicates that recycling of aggregates from demolition wastes arising from end of life PPS would not be limited by the potential leaching of heavy metals, including re-use within another PPS. This would minimise dependence on virgin aggregates and hence reduce rate of exploitation of natural resources and improve sustainability score card of SuDS.


Assuntos
Drenagem Sanitária , Metais Pesados , Poluentes Químicos da Água , Monitoramento Ambiental , Hidrocarbonetos , Reciclagem , Poluição da Água/estatística & dados numéricos
2.
Environ Sci Pollut Res Int ; 26(26): 26563-26576, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31292865

RESUMO

In order to mitigate urban flooding and combined sewer overflows, an integrated assessment method was proposed to identify the optimum reconstruction scheme of a drainage system by considering environment, economy, and society. The integrated assessment framework consisted of the drainage system model establishment, analytic hierarchy process theory, and regret value method. Five drainage system reconstruction schemes for Chaohu city were proposed in this study, and they were evaluated according to nine assessment factors by the integrated assessment method at the initial and future stages. The integrated assessment results show that setting up interceptive equipment for a combined drainage network is the optimal reconstruction scheme at both the initial and future stages of the life cycle. This means that an interceptive combined drainage network is better than a separate drainage network or setting up storage tanks in particular situations from a comprehensive perspective.


Assuntos
Drenagem Sanitária , Inundações , Cidades , Drenagem Sanitária/métodos , Modelos Teóricos
3.
Water Res ; 162: 11-21, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31254882

RESUMO

Urban drainage system (UDS) researchers have applied the concept of resilience for minimizing the magnitude and duration of urban flooding in response to climate change. Currently, the relationship between conventional design and resilience analysis still remains unknown, while persistent rain has not been included in resilience assessment. The present study proposes new metrics by means of resilience profile graph for UDS stressed by synthetic short-duration storms and real persistent rains. The graph unifies the concepts of reliability, robustness, resilience and failure, as well as design standards for sewer surcharging, sewer flooding and property flooding, which are linked into curves to show a complete performance under climate stress scenarios. The obtained results show that resilience profile curves for short-duration storms are well fitted by power functions with coefficient of determination 98.13%-99.9%. Chicago hyetograph was used as critical input hyetograph where the error range was -0.34%-6.83% compared with actual hyetograph. Resilience profile graphs for persistent rains reveal that resilience assessment based on short-duration storms underestimates the effect of persistent rains, and it can be obtained by using segmental and reference reliability metrics to reduce working time from weeks to hours. For the rain of the same intensity, resilience to persistent rain was 18.4-33.1% lower than for single rains. Threat of persistent rain doesn't fall under the rains of high intensity but under large rainfall in total (which exceeds 25% of local annual rainfall), while re-planning water landscape as retarding basin reduces the impact of persistent rains to 5.8-11.8%.


Assuntos
Modelos Teóricos , Chuva , Chicago , Cidades , Mudança Climática , Drenagem Sanitária , Inundações , Reprodutibilidade dos Testes
4.
Water Sci Technol ; 79(6): 1060-1070, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31070586

RESUMO

Brazil faces a severe lack of wastewater coverage. Even in urban areas, wastewater is directly disposed of in watercourses without any treatment for a large part of the population. Although the federal, state, and local governments have invested in water and wastewater services (WWS), the expected results have not been achieved. To overcome this problem, the present paper provides an opportunity to observe an ex-ante regulatory impact assessment (RIA) as a policy tool in Brazil. The regulatory policy options will be appraised through the multiple criteria decision analysis (MCDA) according to the following objectives: (i) protect the customers with respect to social aspects; (ii) safeguard the economic, operational and infrastructure sustainability; and (iii) protect the environment. The results show that by making decisions based on evidence, policy makers should reduce the households not connected to wastewater services by 75% and for that they should incur BRL 33 million to the year 2023. Hence, the extra revenues to be obtained with these new connections are capable of making a surplus estimated as BRL 42 million for the same period. This study promotes the use of RIA as a rational, robust and transparent decision framework by the regulatory agencies worldwide.


Assuntos
Drenagem Sanitária/métodos , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias , Brasil , Tomada de Decisões , Técnicas de Apoio para a Decisão , Drenagem Sanitária/legislação & jurisprudência , Política Ambiental
5.
Water Sci Technol ; 79(6): 1113-1122, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31070591

RESUMO

Sediment deposition in sewers and urban drainage systems has great effect on the hydraulic capacity of the channel. In this respect, the self-cleansing concept has been widely used for sewers and urban drainage systems design. This study investigates the bed load sediment transport in sewer pipes with particular reference to the non-deposition condition in clean bed channels. Four data sets available in the literature covering wide ranges of pipe size, sediment size and sediment volumetric concentration have been utilized through applying decision tree (DT), generalized regression neural network (GR) and multivariate adaptive regression splines (MARS) techniques for modeling. The developed models have been compared with conventional regression models available in the literature. The model performance indicators, showed that DT, GR and MARS models outperform conventional regression models. Result shows that GR and MARS models are comparable in terms of calculating particle Froude number and performing better than DT. It is concluded that conventional regression models generally overestimate particle Froude number for the non-deposition condition of sediment transport, while DT, GR and MARS outputs are close to their measured counterparts.


Assuntos
Árvores de Decisões , Drenagem Sanitária/estatística & dados numéricos , Sedimentos Geológicos/análise , Modelos Estatísticos , Redes Neurais de Computação , Poluição da Água/estatística & dados numéricos , Análise Multivariada , Eliminação de Resíduos Líquidos/estatística & dados numéricos
6.
Water Sci Technol ; 79(2): 334-341, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30865604

RESUMO

China has achieved significant progress on wastewater treatment and aquatic environmental protection. However, leakage (in- and exfiltration) of sewer systems is still an issue. By using the statistical data of water and wastewater in 2016 in China, and the person loads (PLs) of water and wastewater in Singapore, the leakage fractions of hydraulic flow, organic carbon (COD), nitrogen (N) and phosphorus (P) mass loading, and in-sewer COD biological removal in the sewer systems of China (except Hong Kong, Macau and Taiwan), Shanghai, Guangzhou and Beijing were reported for the first time. The fractions of hydraulic flow infiltration (13%, Shanghai and Guangzhou) and exfiltration (39%, China) were calculated. Except Beijing, whose sewer networks are under appropriate management with small leakage fractions, the exfiltration fractions of COD (including in-sewer biological COD removal) ranged from 41% (Shanghai) to 66% (China) and averaged 55%; N ranged from 18% (Shanghai) to 48% (China) and averaged 33%; and P ranged from 23% (Shanghai and Guangzhou) to 44% (China) and averaged 30%. The exfiltrated sewage, COD, N and P not only wastes resources, but also contaminates the aquatic environment (especially groundwater) and contributes to 'black and odorous water bodies'. In- and exfiltration in the sewer network leads to low influent COD concentration, C/N ratio and high inorganic solids and inert particulate COD concentrations of many municipal wastewater treatment plants (WWTPs) causing high cost for nutrient removal, poor resource recovery, additional reactor/settler volume requirement and other operational problems. Therefore, tackling sewer leakage is of primary importance to today's environment in China. Recommendations for the inspection of sewer systems and the rehabilitation of damaged sewers as well as the development of design and operation guidelines of municipal WWTPs tailored to the specific local sewage characteristics and other conditions are proposed.


Assuntos
Esgotos , Eliminação de Resíduos Líquidos/métodos , Poluição Química da Água/estatística & dados numéricos , China , Drenagem Sanitária , Odorantes , Eliminação de Resíduos Líquidos/economia , Eliminação de Resíduos Líquidos/estatística & dados numéricos , Águas Residuárias/análise , Águas Residuárias/química , Poluição Química da Água/análise , Poluição Química da Água/economia
7.
Sci Total Environ ; 612: 1042-1057, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-28892845

RESUMO

In the field of rehabilitation of separate sanitary sewer systems, a large number of technical, environmental, and economic aspects are often relevant in the decision-making process, which may be modelled as a multi-objective optimization problem. Examples are those related with the operation and assessment of networks, optimization of structural, hydraulic, sanitary, and environmental performance, rehabilitation programmes, and execution works. In particular, the cost of investment, operation and maintenance needed to reduce or eliminate Infiltration from the underground water table and Inflows of storm water surface runoff (I/I) using rehabilitation techniques or related methods can be significantly lower than the cost of transporting and treating these flows throughout the lifespan of the systems or period studied. This paper presents a comprehensive I/I cost-benefit approach for rehabilitation that explicitly considers all elements of the systems and shows how the approximation is incorporated as an objective function in a general evolutionary multi-objective optimization model. It takes into account network performance and wastewater treatment costs, average values of several input variables, and rates that can reflect the adoption of different predictable or limiting scenarios. The approach can be used as a practical and fast tool to support decision-making in sewer network rehabilitation in any phase of a project. The fundamental aspects, modelling, implementation details and preliminary results of a two-objective optimization rehabilitation model using a genetic algorithm, with a second objective function related to the structural condition of the network and the service failure risk, are presented. The basic approach is applied to three real world cases studies of sanitary sewerage systems in Coimbra and the results show the simplicity, suitability, effectiveness, and usefulness of the approximation implemented and of the objective function proposed.


Assuntos
Drenagem Sanitária , Água Subterrânea , Movimentos da Água , Modelos Teóricos , Portugal , Águas Residuárias
8.
Water Sci Technol ; 76(11-12): 2918-2927, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29210679

RESUMO

Inflow and infiltration are important aspects of sewerage systems that need to be considered during the design stage and constantly monitored once the sewerage system is in operation. The aim of this research is to analyse the relationship of rainfall as well as inflow infiltration with sewage flow patterns through data collected from fieldwork. Three sewer pipelines were selected at the residential areas of Taman Lepar Hilir Saujana, Bandar Putra and Kota Sas for data collection. Sewage flow data were collected in terms of flowrate, velocity and depth of flow using flowmeters with ultrasonic sensors that utilize the continuous Doppler effect in the sewer pipelines, while rainfall intensity data were collected using rain gauges installed at the study locations. Based on the result, the average infiltration rates of Qpeak and Qave for the locations were 17% and 21%, which exceeded the respective values of 5% and 10% stated in Hammer and Hammer. The flowrate of wastewater in the sewer pipelines was found to be directly proportional to rainfall. These findings indicate that the sewer pipelines in the study areas may have been affected by capacity reduction, whereas the sewerage treatment plants receiving the wastewater influent may have been overloaded.


Assuntos
Cidades , Drenagem Sanitária , Chuva , Esgotos , Águas Residuárias , Malásia , Movimentos da Água
9.
Water Environ Res ; 89(10): 1876-1927, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28954686

RESUMO

A summary of 246 studies published in 2016 on topics related to the characterization and management of urban stormwater runoff is presented in the following review. The review is structured along three major topical areas: (1) general characterization of stormwater quantity and quality; (2) engineered systems for stormwater control and treatment, including erosion and sediment control practices, constructed stormwater ponds and wetlands, bioretention, permeable pavement, greenroofs, and rainwater harvesting and (3) watershedscale application of stormwater treatment and control practices. Common research themes and needs highlighted throughout this review include efforts to better understand stormwater transport and treatment mechanisms and their representation in models, advancements to optimize the design of stormwater control measures to meet specific hydrologic and/or water quality targets, and increasing understanding of the biophysical and social factors that influence watershed-scale implementation of low impact development and other stormwater control measures.


Assuntos
Drenagem Sanitária/métodos , Chuva , Eliminação de Resíduos Líquidos/métodos , Hidrologia , Lagoas , Movimentos da Água , Qualidade da Água , Áreas Alagadas
10.
Artigo em Inglês | MEDLINE | ID: mdl-28777324

RESUMO

Host-associated genetic markers that allow for fecal source identification have been used extensively as a diagnostic tool to determine fecal sources within watersheds, but have not been used in routine monitoring to prioritize remediation actions among watersheds. Here, we present a regional assessment of human marker prevalence among drainages that discharge to the U.S. southern California coast. Approximately 50 samples were analyzed for the HF183 human marker from each of 22 southern California coastal drainages under summer dry weather conditions, and another 50 samples were targeted from each of 23 drainages during wet weather. The HF183 marker was ubiquitous, detected in all but two sites in dry weather and at all sites during wet weather. However, there was considerable difference in the extent of human fecal contamination among sites. Similar site ranking was produced regardless of whether the assessment was based on frequency of HF183 detection or site average HF183 concentration. However, site ranking differed greatly between dry and wet weather. Site ranking also differed greatly when based on enterococci, which do not distinguish between pollution sources, vs. HF183, which distinguishes higher risk human fecal sources from other sources, indicating the additional value of the human-associated marker as a routine monitoring tool.


Assuntos
Bactérias/isolamento & purificação , Drenagem Sanitária , Fezes/microbiologia , Poluentes da Água/análise , Bactérias/genética , California , Monitoramento Ambiental , Humanos , Microbiologia da Água , Tempo (Meteorologia)
11.
BMJ Open ; 7(3): e012719, 2017 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-28363920

RESUMO

INTRODUCTION: Government efforts to address massive shortfalls in rural water and sanitation in India have centred on construction of community water sources and toilets for selected households. However, deficiencies with water quality and quantity at the household level and community coverage and actual use of toilets have led Gram Vikas, a local non-governmental organization in Odisha, India, to develop an approach that provides household-level piped water connections contingent on full community-level toilet coverage. METHODS: This matched cohort study was designed to assess the effectiveness of a combined piped water and sanitation intervention. Households with children <5 years in 45 randomly selected intervention villages and 45 matched control villages will be followed over 17 months. The primary outcome is prevalence of diarrhoeal diseases; secondary health outcomes include soil-transmitted helminth infection, nutritional status, seroconversion to enteric pathogens, urogenital infections and environmental enteric dysfunction. In addition, intervention effects on sanitation and water coverage, access and use, environmental fecal contamination, women's empowerment, as well as collective efficacy, and intervention cost and cost-effectiveness will be assessed. ETHICS AND DISSEMINATION: The study protocol has been reviewed and approved by the ethics boards of the London School of Hygiene and Tropical Medicine, UK and KIIT University, Bhubaneswar, India. Findings will be disseminated via peer-reviewed literature and presentation to stakeholders, government officials, implementers and researchers. TRIAL REGISTRATION NUMBER: NCT02441699.


Assuntos
Diarreia/epidemiologia , Drenagem Sanitária , Enterite/epidemiologia , Enteropatias Parasitárias/epidemiologia , Banheiros , Abastecimento de Água , Aparelho Sanitário , Pré-Escolar , Estudos de Coortes , Análise Custo-Benefício , Meio Ambiente , Características da Família , Fezes , Humanos , Índia/epidemiologia , Lactente , Recém-Nascido , Estado Nutricional , Organizações , Infecções Respiratórias/epidemiologia , Saneamento , Soroconversão
12.
PLoS One ; 11(4): e0153287, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27070781

RESUMO

In intensive agricultural systems runoff is one of the major potential diffuse pollution pathways for pesticides and poses a risk to surface water. Ditches are common in the Po Valley and can potentially provide runoff mitigation for the protection of watercourses. The effectiveness depends on ditch characteristics, so there is an urgent need for site-specific field trials. The use of a fugacity model (multimedia model) can allows recognition of the mitigation main processes. A field experiment was conducted in order to evaluate the mitigation capacity of a typical vegetated ditch, and results were compared with predictions by a fugacity model. To evaluate herbicide mitigation after an extreme runoff, the ditch was flooded with water containing mesotrione, S-metolachlor and terbuthylazine. Two other subsequent floods with uncontaminated water were applied 27 and 82 days later to evaluate herbicides release. Results show that the ditch can immediately reduce runoff concentration of herbicides by at least 50% even in extreme flooding conditions. The half-distances were about 250 m. As a general rule, a runoff of 1 mm from 5 ha is mitigated by 99% in 100 m of vegetated ditch. Herbicides retention in the vegetated ditch was reversible, and the second flood mobilized 0.03-0.2% of the previous one, with a concentration below the drinking water limit of 0.1 µg L(-1). No herbicide was detected in the third flood, because the residual amount in the ditch was too low. Fugacity model results show that specific physical-chemical parameters may be used and a specific soil-sediment-plant compartment included for modelling herbicides behaviour in a vegetated ditch, and confirm that accumulation is low or negligible for herbicides with a half-life of 40 days or less. Shallow vegetated ditches can thus be included in a general agri-environment scheme for the mitigation of pesticides runoff together with wetlands and linear buffer strips. These structures are present in the landscape, and their environmental role can be exploited by proper management.


Assuntos
Praguicidas/toxicidade , Poluição Química da Água/prevenção & controle , Agricultura/métodos , Conservação dos Recursos Naturais , Drenagem Sanitária/métodos , Inundações , Meia-Vida , Herbicidas/farmacocinética , Herbicidas/toxicidade , Itália , Modelos Teóricos , Praguicidas/farmacocinética , Plantas/metabolismo , Gestão de Riscos , Solo/química , Poluentes Químicos da Água/farmacocinética , Poluentes Químicos da Água/toxicidade
13.
Parasitol Res ; 115(4): 1711-20, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26809340

RESUMO

In urban environments, catch basins serve as major developmental and resting sites for anthropophilic and zoophilic mosquitoes. However, the use of this habitat is inconsistent, with abundance of larvae varying significantly across catch basins at a fine spatial scale. During seasonal summer investigations on mosquito species composition, their spatial and temporal distribution and the environmental characteristic of the breeding sites in the underground storm drain systems of the Wroclaw urban area (SW Poland) were assessed from May to September in 2012-2013. The study was conducted in order to develop a rational strategy to control mosquito populations and prevent the potential human exposure to mosquito-transmitted pathogens. Mosquito larvae and pupae were collected and identified weekly from 100 regularly inspected street catch basins located in the town center. All existing and potential breeding habitats in the study area were recorded using a GPS receiver (Magellan MobileMapper CX) and transferred to the computer database. Collected data on the geographical location of inspected breeding places, water quality parameters in inspected catch basins, daily temperature, and precipitation were imposed on orthophotomap in ArcGIS (ESRI, USA). Water quality parameters including pH, electrical conductivity, and water temperature were measured by standard methods. Chemical water analysis of cations (Na(+), NH4 (+), K(+), Mg(2+), Ca(2+)) and anions (Cl(-), NO2 (-), NO3 (-), SO4 (2-)) were carried out using Waters Alliance high-performance liquid chromatograph (HPLC) 2695 with 432 Conductivity Detector and 2998 Photodiode Array Detector, an IC-Pak Anion HR column (glauconate/borate eluent) and IC-Pak Cation M/D column (EDTA/HNO3 eluent). Over two seasonal studies and 3739 samplings in total, 3669 mosquito larvae and 274 pupae/1 dip (from 0 to 110 individuals/dip) were collected by dipper. Culex pipiens s.l. (L.) and Cx. torrentium (Martini) prevailed at all catch basins of the study area as the predominant species. In all examined catch basins, autogenous individuals dominated by far. Breeding activity was first detected in early May. Peak abundance of Culex spp. population in many catch basins was observed in June 2012 and August 2013 when average daily temperatures were increasing and rainfall had declined. Dry periods between rainfalls varied during 2 years of the study period and were noted on June 2012 as well as on July and August 2013. Organically enriched catch basins with significant higher concentrations of Na(+) and NO3 (-) were found to be more productive breeding habitats. Differences in the Culex immature stage density based on the variables of habitat type, temperature, and precipitation support the need for ongoing surveillance in communities to guide public health officials in planning for and prioritizing mosquito control efforts.


Assuntos
Culex/fisiologia , Animais , Cidades , Drenagem Sanitária , Meio Ambiente , Larva/fisiologia , Controle de Mosquitos/métodos , Polônia , Pupa , Estações do Ano , Temperatura , Água
14.
Ying Yong Sheng Tai Xue Bao ; 26(6): 1901-12, 2015 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-26572048

RESUMO

Low impact development ( LID), as an innovative technology for stormwater management, is effective to mitigate urban flooding and to detain pollutants. This paper systemically introduced the LID technology system, and summarized the reduction effects of three typical LID facilities (i.e. , bio-retention, green roof and permeable pavement) on stormwater runoff and main pollutants in recent literature, as well as research outcomes and experiences of LID technology on model simulation, cost-benefit analysis and management system. On this basis, we analyzed the problems and limitations of current LID technology studies. Finally, some suggestions about future research directions, appropriate design and scientific management were put forth. This work intended to provide scientific basis and suggestions for widespread use and standard setting of LID technology in China by referencing overseas studies.


Assuntos
Cidades , Drenagem Sanitária , Chuva , Abastecimento de Água , China , Análise Custo-Benefício , Inundações , Modelos Teóricos , Poluentes da Água/análise
15.
Water Sci Technol ; 72(8): 1375-82, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26465308

RESUMO

Eroded sewer sediments are a significant source of organic matter discharge by combined sewer overflows. Many authors have studied the erosion and sedimentation processes at the scale of a section of sewer pipe and over short time periods. The objective of this study was to assess these processes at the scale of an entire sewer network and over 1 month, to understand whether phenomena observed on a small scale of space and time are still valid on a larger scale. To achieve this objective the continuous monitoring of turbidity was used. First, the study of successive rain events allows observation of the reduction of the available sediment and highlights the widely different erosion resistance for the different sediment layers. Secondly, calculation of daily chemical oxygen demand (COD) fluxes during the entire month was performed showing that sediment storage in the sewer pipe after a rain period is important and stops after 5 days. Nevertheless, during rainfall events, the eroded fluxes are more important than the whole sewer sediment accumulated during a dry weather period. This means that the COD fluxes promoted by runoff are substantial. This work confirms, with online monitoring, most of the conclusions from other studies on a smaller scale.


Assuntos
Drenagem Sanitária , Nefelometria e Turbidimetria , Chuva , Tempo (Meteorologia)
16.
Water Sci Technol ; 71(10): 1471-7, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26442488

RESUMO

Short-duration precipitation bursts can cause substantial property damage and pose operational risks for wastewater managers. The objective of this study was to assess the present and possible future flood hazard in the combined sewer system in Reykjavik city centre. The catchment is characterised by two hills separated by a plain. A large portion of the pipes in the aging network are smaller than the current minimum diameter of 250 mm. Runoff and sewer flows were modelled using the MIKE URBAN software package incorporating both historical precipitation and synthetic storms derived from annual maximum rainfall data. Results suggest that 3% of public network manholes were vulnerable to flooding during an 11-year long rainfall sequence. A Chicago Design Storm (CDS) incorporating a 10-minute rainfall burst with a 5-year return period predicted twice as many flooded manholes at similar locations. A 20% increase in CDS intensity increased the number of flooded manholes and surface flood volume by 70% and 80%, respectively. The flood volume tripled if rainfall increase were combined with urban re-development, leading to a 20% increase in the runoff coefficient. Results highlight the need for reducing network vulnerabilities, which include decreased pipe diameters and low or drastically varying pipe grades.


Assuntos
Inundações , Esgotos/análise , Chicago , Cidades , Drenagem Sanitária , Humanos , Modelos Teóricos , Chuva/química , Fatores de Tempo
17.
Environ Sci Technol ; 49(14): 8307-14, 2015 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-26066313

RESUMO

The robustness of a range of watershed-scale "green" and "gray" drainage strategies in the future is explored through comprehensive modeling of a fully integrated urban wastewater system case. Four socio-economic future scenarios, defined by parameters affecting the environmental performance of the system, are proposed to account for the uncertain variability of conditions in the year 2050. A regret-based approach is applied to assess the relative performance of strategies in multiple impact categories (environmental, economic, and social) as well as to evaluate their robustness across future scenarios. The concept of regret proves useful in identifying performance trade-offs and recognizing states of the world most critical to decisions. The study highlights the robustness of green strategies (particularly rain gardens, resulting in half the regret of most options) over end-of-pipe gray alternatives (surface water separation or sewer and storage rehabilitation), which may be costly (on average, 25% of the total regret of these options) and tend to focus on sewer flooding and CSO alleviation while compromising on downstream system performance (this accounts for around 50% of their total regret). Trade-offs and scenario regrets observed in the analysis suggest that the combination of green and gray strategies may still offer further potential for robustness.


Assuntos
Tomada de Decisões , Meio Ambiente , Águas Residuárias , Cidades , Drenagem Sanitária
18.
Water Res ; 81: 27-37, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26024961

RESUMO

Managed aquifer recharge (MAR) has been developed in many countries to limit the risk of urban flooding and compensate for reduced groundwater recharge in urban areas. The environmental performances of MAR systems like infiltration basins depend on the efficiency of soil and vadose zone to retain stormwater-derived contaminants. However, these performances need to be finely evaluated for stormwater-derived dissolved organic matter (DOM) that can affect groundwater quality. Therefore, this study examined the performance of MAR systems to process DOM during its transfer from infiltration basins to an urban aquifer. DOM characteristics (fluorescent spectroscopic properties, biodegradable and refractory fractions of dissolved organic carbon -DOC-, consumption by micro-organisms during incubation in slow filtration sediment columns) were measured in stormwater during its transfer through three infiltration basins during a stormwater event. DOC concentrations sharply decreased from surface to the aquifer for the three MAR sites. This pattern was largely due to the retention of biodegradable DOC which was more than 75% for the three MAR sites, whereas the retention of refractory DOC was more variable and globally less important (from 18% to 61% depending on MAR site). Slow filtration column experiments also showed that DOC retention during stormwater infiltration through soil and vadose zone was mainly due to aerobic microbial consumption of the biodegradable fraction of DOC. In parallel, measurements of DOM characteristics from groundwaters influenced or not by MAR demonstrated that stormwater infiltration increased DOC quantity without affecting its quality (% of biodegradable DOC and relative aromatic carbon content -estimated by SUVA254-). The present study demonstrated that processes occurring in soil and vadose zone of MAR sites were enough efficient to limit DOC fluxes to the aquifer. Nevertheless, the enrichments of DOC concentrations measured in groundwater below infiltration basins need to be considered in future studies to especially assess their impact on groundwater quality.


Assuntos
Carbono/análise , Drenagem Sanitária/métodos , Água Subterrânea/química , Solo/química , Filtração , Água Subterrânea/microbiologia , Chuva , Microbiologia do Solo , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química
19.
Environ Sci Pollut Res Int ; 22(20): 15712-21, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26022395

RESUMO

In recent years, due to global climate change and rapid urbanization, extreme weather events occur to the city at an increasing frequency. Waterlogging is common because of heavy rains. In this case, the urban drainage system can no longer meet the original design requirements, resulting in traffic jams and even paralysis and post a threat to urban safety. Therefore, it provides a necessary foundation for urban drainage planning and design to accurately assess the capacity of the drainage system and correctly simulate the transport effect of drainage network and the carrying capacity of drainage facilities. This study adopts InfoWorks Integrated Catchment Management (ICM) to present the two combined sewer drainage systems in Yangpu District, Shanghai (China). The model can assist the design of the drainage system. Model calibration is performed based on the historical rainfall events. The calibrated model is used for the assessment of the outlet drainage and pipe loads for the storm scenario currently existing or possibly occurring in the future. The study found that the simulation and analysis results of the drainage system model were reliable. They could fully reflect the service performance of the drainage system in the study area and provide decision-making support for regional flood control and transformation of pipeline network.


Assuntos
Drenagem Sanitária/métodos , Esgotos/análise , Eliminação de Resíduos Líquidos/instrumentação , Eliminação de Resíduos Líquidos/métodos , China , Cidades , Clima , Conservação dos Recursos Naturais , Inundações , Modelos Teóricos , Chuva , Urbanização
20.
Salud Publica Mex ; 57(1): 22-8, 2015.
Artigo em Espanhol | MEDLINE | ID: mdl-25629276

RESUMO

OBJECTIVE: Explain the variation in child malnutrition (CM), understood as low height for age (0 to 5 years old) for the period 1999-2006. MATERIALS AND METHODS: State estimations of child malnutrition and several indicators of subjacent probable causes of CM were employed, such as poverty indices, state product per capita, women scholar attainment and access to health and the sewage system. Panel data regression analysis with fixed and random effects were used to analyze the data. RESULTS: The results indicate that the lack to access to health and sewage systems and poverty worsen CM, whereas women education helps to diminish CM. CONCLUSION: The study shows that infrastructure variables explain a significant part of the recent variation in DI across Mexican states, and that economic growth is not a sufficient condition to diminish DI.


Assuntos
Transtornos da Nutrição Infantil/epidemiologia , Drenagem Sanitária/estatística & dados numéricos , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Renda/estatística & dados numéricos , Adolescente , Adulto , Estatura , Criança , Transtornos da Nutrição Infantil/economia , Transtornos da Nutrição Infantil/prevenção & controle , Pré-Escolar , Desenvolvimento Econômico , Escolaridade , Feminino , Humanos , Lactente , Masculino , México/epidemiologia , Modelos Teóricos , Inquéritos Nutricionais , Pobreza , Fatores Socioeconômicos
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