Search results for " drainage"
showing 10 items of 116 documents
Identifiability analysis for receiving water body quality modelling
2009
In urban drainage, new computational possibilities have supported the development of new integrated approaches aimed at joint water quantity and quality analysis of the whole urban drainage system. Although the benefit of an integrated approach has been widely demonstrated, to date, several aspects prevent its applicability such as scarce availability of field data if compared with model complexity. These aspects sometimes prevent the correct estimation of parameters thus leading to large uncertainty in modelling response. This is a typical parameter identifiability problem that is discussed in the present paper evaluating the effect of identifiability procedures in increasing operator conf…
Stormwater infiltration trenches: a conceptual modelling approach.
2009
In recent years, limitations linked to traditional urban drainage schemes have been pointed out and new approaches are developing introducing more natural methods for retaining and/or disposing of stormwater. These mitigation measures are generally called Best Management Practices or Sustainable Urban Drainage System and they include practices such as infiltration and storage tanks in order to reduce the peak flow and retain part of the polluting components. The introduction of such practices in urban drainage systems entails an upgrade of existing modelling frameworks in order to evaluate their efficiency in mitigating the impact of urban drainage systems on receiving water bodies. While s…
Modelling of E. colidistribution in coastal areas subjected to combined sewer overflows
2013
Rivers, lakes and the sea were the natural receivers of raw urban waste and storm waters for a long time but the low sustainability of such practice, the increase of population and a renewed environmental sensibility increased researcher interest in the analysis and mitigation of the impact of urban waters on receiving water bodies (RWB). In Europe, the integrated modelling of drainage systems and RWB has been promoted as a promising approach for implementing the Water Framework Directive. A particular interest is given to the fate of pathogens and especially of Escherichia coli, in all the cases in which an interaction between population and the RWB is foreseen. The present paper aims to p…
Neumonía adquirida en la comunidad: tratamiento de los casos complicados y en situaciones especiales. Documento de consenso de la Sociedad Española d…
2015
Resumen: Desde hace más de una década, los casos complicados de neumonía adquirida en la comunidad, fundamentalmente con empiema pleural o formas necrosantes, comenzaron a ser más frecuentes en niños, según la amplia documentación procedente de numerosos países. El abordaje terapéutico óptimo de estos casos, tanto desde el punto de vista médico (antibióticos, fibrinolíticos) como técnico-quirúrgico, (drenaje pleural, videotoracoscopia) continúa siendo controvertido. En este documento, la Sociedad Española de Infectología Pediátrica y la Sociedad Española de Neumología Pediátrica revisan la evidencia científica y proponen unas pautas consensuadas de tratamiento de estos casos, fundamentalmen…
Flow hydraulic characteristics determining the occurrence of either smooth or abrupt sewer pressurization
2014
Laboratory experiments showed that pipe pressurization consequent on a drastic reduction in the downstream discharge can occur either by a gradual rising of the free-surface (“smooth” pressurization) or by propagation of a front filling the whole cross-section (“abrupt” pressurization). This study examines the free-surface flow characteristics that determine smooth or abrupt pressurization pattern through a theoretical approach using dimensionless variables. A critical flow rate value, which separates the pressurization patterns, exists for any given pipe diameter. For flow rates higher than this specific value, only abrupt pressurization occurs. For lower flow rates, either smooth or abrup…
Boron and lithium behaviour in river waters under semiarid climatic conditions
2022
Boron (B) and Lithium (Li) concentrations were studied in the Platani river, one of the most important catchments of South-Central Sicily which is under semiarid climatic conditions for roughly eight months to a year. In this area, evaporites result in potential B and Li sources for surface waters. Results from river waters have measured ionic strength values between 0.1 and 4.54 M. B and Li distributions in these waters were studied in colloidal (CF, extracted by ultrafiltration from the 0.45 μm filtrate) and total dissolved (TDF) fractions and in fractions extracted from corresponding riverbed sediments, according to changes of the B/Li ratio. In river waters, CF and TDF showed very simil…
Endoskopische ablative Verfahren bei Gallengangstumoren – Effektivität der photodynamischen Therapie und der Radiofrequenzablation
2015
Nur etwa 20–30 % der Patienten mit hilarem cholangiozellularen Karzinom (CCC) konnen bei Diagnosestellung kurativ operiert werden, da erst bei fortgeschrittenem Tumorstadium Symptome auftreten 3 . Daher konnen den meisten Patienten mit dieser Tumorentitat lediglich palliative Therapiekonzepte angeboten werden. Die Effektivitat der photodynamischen Therapie (PDT) wurde in 2 kontrolliert randomisierten sowie in weiteren kontrollierten Studien nachgewiesen. Eine endoskopische Drainage in Kombination mit einer intraluminalen PDT stellte bislang das beste palliative Therapiekonzept dar [1, 3]. Die Radiofrequenzablation (RFA) ist ein neues endoskopisches Verfahren im Rahmen des palliativen Therap…
How to tackle the stringent sulfate removal requirements in mine water treatment-A review of potential methods.
2018
Abstract Sulfate (SO₄²⁻) is a ubiquitous anion in natural waters. It is not considered toxic, but it may be detrimental to freshwater species at elevated concentrations. Mining activities are one significant source of anthropogenic sulfate into natural waters, mainly due to the exposure of sulfide mineral ores to weathering. There are several strategies for mitigating sulfate release, starting from preventing sulfate formation in the first place and ending at several end-of-pipe treatment options. Currently, the most widely used sulfate-removal process is precipitation as gypsum (CaSO₄·2H₂O). However, the lowest reachable concentration is theoretically 1500 mg L⁻¹ SO₄²⁻ due to gypsum’s solu…
Pluvial flooding in urban areas: the role of surface drainage efficiency
2018
Pluvial flooding in urban areas may derive from the limited or temporarily reduced efficiency of surface drainage, even when the underlying storm sewers are properly designed. This study focuses on the impact of uncertainties in the operational condition of the surface drainage system on pluvial flood hazard. The flood propagation model FLURB-2D is implemented on a selected study area in the town of Genoa (Italy). Synthetic hyetographs based on the Chicago and bivariate copula methods with suitable return periods are used as input. While simulating the design rainfall, inlet operational conditions are varied stochastically using a Monte Carlo approach. Results confirm that microtopography h…
An urban drainage stormwater quality model: model development and uncertainty quantification
2010
Summary The evaluation of urban stormwater quality is of relevant importance for urban drainage, and mathematical models may be of great interest in this respect. To date, several detailed mathematical models are available to predict stormwater quantity–quality characteristics in urban drainage systems. However, only a few models take sewer sediments into account, considering their cohesive-like properties that influence the build-up process of the pollutant load. Furthermore, the model data requirements, especially for the quality aspects, are extensive, which limit their applicability and affect model results with large uncertainty. Uncertainty analysis provides a measure or index regardi…