Estudio experimental y numérico de los sistemas de captación de fondo

[ESP] Los sistemas de captación de fondo pueden constituir infraestructuras eficaces para la derivación de caudales en cauces efímeros, donde el transporte de sedimentos alcanza valores importantes. La optimización de estos sistemas para dicho fin supone hoy en día un motivo de investigación en las zonas semiáridas. De forma resumida dichos sistemas de captación de fondo se pueden dividir en las siguientes partes: i) reja de captación; ii) canal de transporte; iii) desarenador. La presente tesis se ha centrado en la reja de captación. Se ha establecido la influencia de la inclinación longitudinal de la reja, así como de las condiciones de aproximación del flujo a la entrada de la reja, a la hora de definir: i) cuantía de caudales derivados; ii) perfil adoptado por la lámina de agua y iii) coeficiente de descarga, entendido éste como la variable obtenida experimentalmente al relacionar el caudal derivado con la altura de energía de aproximación. Mientras diversos autores reconocen esta influencia a partir de trabajos experimentales (Orth, 1954; Frank, 1959; White et al. 1972), otros no consideran apreciable dicha influencia, por no disponer de una campaña experimental con pendientes longitudinales suficientemente amplia (Noseda, 1956) o por centrarse en pendientes longitudinales elevadas, superiores al 35% (19º), y donde dicha influencia deja de apreciarse al analizar el perfil de la lámina de agua (Brunella et al. 2003). Los trabajos han sido realizados en la infraestructura construida en el laboratorio de Hidráulica de la UPCT para rejas con sección en T, e índices de huecos comprendidos entre 0.16 y 0.28 y para pendientes del 0 al 33%. La definición del campo de velocidades y presiones del flujo a lo largo de la reja, mediante PIV y tubo pitot, ha permitido poder establecer la relación entre el coeficiente de descarga y la presión sobre la hendidura (Krochin, 1978), así como las diferencias con lo propuesto por diversos desarrollos teóricos existentes (Castro-Orgaz y Hager, 2011). A partir de los trabajos experimentales y numéricos recogidos en la bibliografía hasta la fecha se ha propuesto un ajuste multiparámetrico partiendo de las variables adimensionales obtenidas de un análisis dimensional. A partir de dicho ajuste se construye un ábaco que arroja el valor del coeficiente de descarga equivalente para diferentes condiciones de número de Froude al inicio de la reja, Fr0, tipo de barra y su espaciamiento, m. El estudio de la sedimentación de los materiales transportados por el flujo en la hendidura de las rejas ha permitido establecer la pendiente longitudinal más eficiente en el 30%. Del mismo modo se ha propuesto el incremento de longitud de reja que contemple dicho fenómeno. Estos trabajos se han llevado a cabo a partir de una campaña experimental con flujos que transportan gravas que ha permitido estudiar el fenómeno de la oclusión de la hendidura de las rejas de fondo. [ENG] Bottom intake systems can become effective infrastructure to derive flows in ephemeral streams, where sediment transport reaches important values. The optimization of these systems is a cause for research in semiarid areas. Briefly, these systems can be divided into the following parts: i) bottom rack; ii) transport channel; iii) sand trap. This thesis has focused on the bottom rack. Influence of longitudinal rack slope, as well as the approach flow conditions, is stablished for the: i) amount of derived flows; ii) profile adopted by the water surface and iii) discharge coefficient, taken as the variable defined experimentally by relating the derived flow rate and energy height. Several authors recognize this influence from experimental work (Orth, 1954; Frank, 1959. White et al 1972). Others do not consider this influence due to lack of sufficiently large slopes measurements (Noseda, 1956), or because them reached values higher than 35% (19°), where such influence is no longer observed when analyzing the water surface profile (Brunella et al. 2003). The work has been carried out in the laboratory of hydraulics of the UPCT for T shaped bars and for rates ranging from 0.16 to 0.28 bar space and slope from 0 to 33%. Velocity field and flow pressures measurements along the racks, using PIV (Particle Image Velocimetry) and pitot tubes, has allowed to establish the relationship between the discharge coefficient and pressure on the slit (Krochin, 1978), as well as differences between existing theoretical developments of pressure field along the flow over the racks (Castro-Orgaz and Hager, 2011). From information of several experimental works carried out to date, a multiparameter adjustment is proposed, based on variables obtained from a dimensional analysis. From this is defined an abacus to obtain the equivalent discharge coefficient value for different conditions as: Froude number at the beginning of the rack, Fr0, bar type and void ratio, m. Finally, the study of sedimentation of materials carried by the flow in the space between bars has established the most efficient longitudinal slope at 30%. Similarly, it has proposed increasing rack length that includes this phenomenon. Experimental test with flow that include gravels are taken in the hydraulic device allowing study of occlusion phenomena.Escuela Internacional de Doctorado de la Universidad Politécnica de CartagenaUniversidad Politécnica de CartagenaPrograma Oficial de Doctorado en Minería, Medio Ambiente y Desarrollo Sostenibl

Fine Sediment Modeling During Storm-Based Events in the River Bandon, Ireland

The River Bandon located in County Cork (Ireland) has been time-continuously monitored by turbidity probes, as well as automatic and manual suspended sediment sampling. The current work evaluates three different models used to estimate the fine sediment concentration during storm-based events over a period of one year. The modeled suspended sediment concentration is compared with that measured at an event scale. Uncertainty indices are calculated and compared with those presented in the bibliography. An empirically-based model was used as a reference, as this model has been previously applied to evaluate sediment behavior over the same time period in the River Bandon. Three other models have been applied to the gathered data. First is an empirically-based storm events model, based on an exponential function for calculation of the sediment output from the bed. A statistically-based approach first developed for sewers was also evaluated. The third model evaluated was a shear stress erosion-based model based on one parameter. The importance of considering the fine sediment volume stored in the bed and its consolidation to predict the suspended sediment concentration during storm events is clearly evident. Taking into account dry weather periods and the bed erosion in previous events, knowledge on the eroded volume for each storm event is necessary to adjust the parameters for each model.The authors acknowledge the funding received through the Visiting Researchers Programme from the Technical University of Cartagena UPCT, Spain, in the period from August to December 2018. The authors also acknowledge the funding received from the Government of Ireland Technological Research Strand I R&D Skills Programme and the support provided by the Irish Environmental Protection Agency and the Irish Office of Public Works. This research received no external funding

Estudio de las mejores prácticas para la gestión de las aguas pluviales y su carga contaminante en zonas urbanas consolidadas y costeras del Mar Menor

A partir del estudio de un caso concreto de evacuación de aguas pluviales procedentes de escorrentía urbanas para evitar que provoquen inundaciones y que los contaminantes que transportan puedan alcanzar zonas de especial protección y alto valor ecológico, trataremos de sentar una serie de criterios aplicables a situaciones similares. El presente proyecto se centra en la zona urbana consolidada costera al Mar Menor denominada “Los Urrutias”, que conforma uno de los múltiples desarrollos urbanos de uso estacional que rodean el Mar Menor en el Término Municipal de Cartagena. Enclavado a las orillas del Mar Menor, en su parte oesteEscuela de Ingeniería de Caminos y Mina

Evaluation of leakages effects in the water supply system of Moratalla (Spain). Póster

One of the risk management requirements is the assessment of the effect of each kind of possible failure. In water supply systems, the most common failures are the pipe leakages. Most leakages can be modelled as orifices in a pipe [1]. At this paper, a leakage pattern is defined for each of the 300 pipes in Moratalla’s water supply system. That leakage pattern is defined as an orifice whose diameter length is 1/10 of the pipe diameter. Epanet-Octave is a GNU Octave wrapper that makes easy and vector oriented the use of EPANET ToolKit. Epanet-Octave library has been used to carry out a simulation for each pipe which may have a leakage. Each simulation lasts a whole simulated day to include leakage effects for the different pressures and demands that happen during the day. Then, the results are summarised by using an index which weights the negative effect of the leakages. Usually leakages are evaluated mainly by the energy waste in pumping that water [2-3]. In this case, the suggested index accounts for leakage flow rates, water quality deterioration and service deterioration. Leakage flow rates effects are included through the maximum leakage flow rate (in time) and its average value, which in this case is proportional to the energy cost used in other works as the system distributes the water from the reservoirs to customers by gravity. Water quality deterioration is evaluated by the presence of negative pressures around the orifice. Finally, service deterioration is measured through the water that would be supplied below the regulated minimum pressure. This weighted index, which is shown in figure 1, can be used, together with other non-hydraulic factors like pipe-age or pipe-material, to prioritise the maintenance and even the replacement of pipes according to a risk management strategy

Assessing different imaging velocimetry techniques to measure shallow runoff velocities during rain events using an urban drainage physical model

Although surface velocities are key in the calibration of physically based urban drainage models, the shallow water depths developed during non-extreme precipitation and the potential risks during flood events limit the availability of this type of data in urban catchments. In this context, imaging velocimetry techniques are being investigated as suitable non-intrusive methods to estimate runoff velocities, when the possible influence of rain has yet to be analyzed. This study carried out a comparative assessment of different seeded and unseeded imaging velocimetry techniques based on large-scale particle image velocimetry (LSPIV) and bubble image velocimetry (BIV) through six realistic but laboratory-controlled experiments, in which the runoff generated by three different rain intensities was recorded. First, the use of naturally generated bubbles and water shadows and glares as tracers allows unseeded techniques to measure extremely shallow flows. However, these techniques are more affected by raindrop impacts, which even lead to erroneous velocities in the case of high rain intensities. At the same time, better results were obtained for high intensities and in complex flows with techniques that use artificial particles. Finally, the study highlights the potential of these imaging techniques for measuring surface velocities in real field applications as well as the importance of considering rain properties to interpret and assess the results obtained. The robustness of the techniques for real-life applications yet remains to be proven by means of further studies in non-controlled environments.The project receives funding from the Spanish Ministry of Science and Innovation under POREDRAIN project RTI2018-094217-B-C33 (MINECO/FEDER-EU)

Reject brine management: Denitrification and zero liquid discharge (ZLD)—Current status, challenges and future prospects

Water is at the core of sustainable development. Moreover, it is essential for social, economic, and environmental well-being. However, water resource availability has been significantly threatened in the 21st century. In general, freshwater supplies are being depleted by natural and anthropogenic activities, such as rapid population growth, industrialization, and intensive agriculture. In addition, one of the main causes of water resource shortages is water body contamination. Nitrate pollution is considered one of the most pressing global environmental problems, both in surface and groundwater. The literature reveals that numerous nitrogen removal processes have been developed and proposed. To overcome this problem, desalination is a robust and mature technique for obtaining fresh water from saltwater, and is considered an efficient and reliable process. However, there is growing concern about the adverse environmental impacts generated by brine where concentrated rejection by desalination results in high salinity together with chemical residues. To solve this problem, a zero liquid discharge (ZLD) strategy has been proposed in the specific literature. Furthermore, ZLD can be used to treat and recover valuable resources. This study analyzes and discusses the current status of brine treatment technologies targeting ZLD, highlighting their advantages and disadvantages. Technologies based on membranes and thermal energy were also analyzed, and their performance and operating costs were compared. Finally, the different denitrification processes are listed. This ZLD solution is currently considered an essential and compulsory treatment in reject brine to remove nitrate that, because of high concentrations in the environment, is one of the most widespread global contaminants.This work was financially supported by the Life+ European Project (LIFE19 ENV/ES/00447)

Spectroscopy transmittance by LED calibration

Local administrations demand real-time and continuous pollution monitoring in sewer networks. Spectroscopy is a non-destructive technique that can be used to continuously monitor quality in sewers. Covering a wide range of wavelengths can be useful for improving pollution characterization in wastewater. Cost-effective and in-sewer spectrophotometers would contribute to accomplishing discharge requirements. Nevertheless, most available spectrometers are based on incandescent lamps, which makes it unfeasible to place them in a sewerage network for real-time monitoring. This research work shows an innovative calibration procedure that allows (Light-Emitting Diode) LED technology to be used as a replacement for traditional incandescent lamps in the development of spectrophotometry equipment. This involves firstly obtaining transmittance values similar to those provided by incandescent lamps, without using any optical components. Secondly, this calibration process enables an increase in the range of wavelengths available (working range) through a better use of the LED's spectral width, resulting in a significant reduction in the number of LEDs required. Thirdly, this method allows important reductions in costs, dimensions and consumptions to be achieved, making its implementation in a wide variety of environments possible.This research was funded by Seneca Foundation of the Región de Murcia (Spain) and “Hidrogea, Gestión Integral de Aguas de Murcia S.A”. Authors wish to thank the financial support received from the Seneca Foundation of the Región de Murcia (Spain) through the program devoted for training of novel researchers in areas of specific interest for the industry and with a high capacity to transfer the results of the research generate entitled: “Subprograma Regional de Contratos de Formación de Personal Investigador en Universidades y OPIs” (Mod. B, Ref. 20320/FPI/17).Authors wish to thank the financial support received from the Seneca Foundation of the Región de Murcia (Spain) through the program devoted for training of novel researchers in areas of specific interest for the industry and with a high capacity to transfer the results of the research generate entitled: “Subprograma Regional de Contratos de Formación de Personal Investigador en Universidades y OPIs” (Mod. B, Ref. 20320/FPI/17)

Wastewater quality estimation through spectrophotometry-based statistical models

Local administrations are increasingly demanding real-time continuous monitoring of pollution in the sanitation system to improve and optimize its operation, to comply with EU environmental policies and to reach European Green Deal targets. The present work shows a full-scale Wastewater Treatment Plant field-sampling campaign to estimate COD, BOD5, TSS, P, TN and NO3-N in both influent and effluent, in the absence of pre-treatment or chemicals addition to the samples, resulting in a reduction of the duration and cost of analysis. Different regression models were developed to estimate the pollution load of sewage systems from the spectral response of wastewater samples measured at 380-700 nm through multivariate linear regressions and machine learning genetic algorithms. The tests carried out concluded that the models calculated by means of genetic algorithms can estimate the levels of five of the pollutants under study (COD, BOD5, TSS, TN and NO3-N), including both raw and treated wastewater, with an error rate below 4%. In the case of the multilinear regression models, these are limited to raw water and the estimate is limited to COD and TSS, with less than a 0.5% error rateThe authors wish to thank the financial support received from the Seneca Foundation of the Región de Murcia (Spain) through the program devoted to training novel researchers in areas of specific interest for the industry and with a high capacity to transfer the results of the research generated, entitled: “Subprograma Regional de Contratos de Formación de Personal Investigador en Universidades y OPIs” (Mod. B, Ref. 20320/FPI/17)

Proposals of a procedure to asses Pollutographs. Application to Murcia's Combined Sewer Overflows (CSOs). Póster

Directives 91/271/EEC and 93/481/EEC set norms regarding the management of Combined Sewer Overflows. European Commission monitors the implementation status and implementation programmes. In fact, during the year 2019 all the utilities should be able to quantify the pollution spilled during storm events. And afterwards, plans have to be developed in order to reduce the impact of such events. In this paper, we proposed a method to estimate the transported pollution during events as well as to serve as a tool for developing plans to lessen the corresponding pollution. The procedure is divided into three steps: A. Periodical measurements of all relevant pollutants, e.g. total suspended solids and chemical oxygen demand, in wet and dry weather. Such pollutant “concentrations” are correlated with the turbidity, updating the relation among them [1]. B. Continuous measures of the turbidity. Turbidity is continously register in the sewer areas near overflow spillways. Turbidimeters are a very convenient equipment for this purpose [2]. Actually, it is reliable, its measures are very correlated with the total suspended solid concentration and its maintenance is easy. In this way, combining A. and B. turbidity measures provide us a real-time estimation of the pollutant concentration. on real time. C. Assesment of each catchment hydrograph. Depending on the available data, this step could be based on a design, a measured or a simulated hydrograph. In order to apply this methodology to Murcia’s Combined Sewer System, we have used simulated hydrographs based on real measured rainfall. Murcia’s utility has developed a calibrated SWMM model, and therefore, using the rainfall data, it is possible to estimate hydrographs for all the relevant points of the system. D. Estimation of each catchment pollutograph. Combining the pollutant concentration, estimated in the previous steps, with the hydrographs, we can asses how the mass of pollutants are transported. This information allows us to comply with EU Directives, but it will also be useful to design Murcia’s strategy to minimize environmental impacts

Performing calibration of transmittance by single rgb-led within the visible spectrum

Spectrophotometry has proven to be an effective non-invasive technique for the characterization of the pollution load of sewer systems, enabling compliance with new environmental protection regulations. This type of equipment has costs and an energy consumption which make it difficult to place it inside a sewer network for real-time and massive monitoring. These shortcomings are mainly due to the use of incandescent lamps to generate the working spectrum as they often require the use of optical elements, such as diffraction gratings, to work. The search for viable alternatives to incandescent lamps is key to the development of portable equipment that is cheaper and with a lower consumption that can be used in different points of the sewer network. This research work achieved the following results in terms of the measured samples: First, the development a calibration procedure that enables the use of RGB-LED technology as a viable alternative to incandescent lamps, within the range of 510 to 645 nm, with high accuracy. Secondly, demonstration of a simple method to model the transmittance value of a specific wavelength without the need for optical elements, achieving a cost-effective equipment. Thirdly, it provides a simple method to obtain the transmittance based on the combination of RGB colors. Finally its viability is demonstrated for the spectral analysis of wastewater.The authors are grateful for the financial support received from the Seneca Foundation of the Región de Murcia (Spain) through the program devoted to training novel researchers in areas of specific interest for the industry and with a high capacity to transfer the results of the research generated, entitled: “Subprograma Regional de Contratos de Formación de Personal Investigador en Universidades y OPIs” (Mod. B, Ref. 20320/FPI/17)