Person:
Alvarado Martínez, Andrés Omar

Birth Date

1976-09-14

ORCID

0000-0002-9125-1221

Scopus Author ID

7006162056

Afiliación

Universidad de Cuenca, Cuenca, Ecuador
Universidad de Cuenca, Departamento de Recursos Hídricos y Ciencias Ambientales, Cuenca, Ecuador
Universidad de Cuenca, Facultad de Ingeniería, Cuenca, Ecuador

País

Ecuador

Organizational Units

Organizational Unit

Facultad de Ingeniería

La Facultad de Ingeniería, a inicios de los años 60, mediante resolución del Honorable Consejo Universitario, se formalizó la Facultad de Ingeniería de la Universidad de Cuenca, conformada por las escuelas de Ingeniería Civil y Topografía. Esta nueva estructura permitió una mayor especialización y fortalecimiento en áreas clave para el desarrollo regional. Cuenta con programas académicos reconocidos internacionalmente, que promueven y lideran actividades de investigación. Aplica un modelo educativo centrado en el estudiante y con procesos de mejora continua. Establece como prioridad una educación integra, la formación humanística es parte del programa de estudios que complementa a la sólida preparación científico-técnica. Las actividades culturales pertenecen a un programa permanente y activo al interior de nuestras dependencias, a la par de proyectos que desde el alumnado y bajo la supervisión de docentes cumplen con servicios de apoyo a nivel local y regional; promoviendo así una vinculación estrecha con la comunidad.

Job Title

Profesor (T)

Last Name

Alvarado Martínez

First Name

Andrés Omar

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Now showing 1 - 10 of 20

CFD analysis of sludge accumulation and hydraulic performance of a waste stabilization pond
(2012) Alvarado Martínez, Andrés Omar; Sánchez Cordero, Esteban Remigio; Durazno, Galo; Vesvikar, Mehul; Nopens, Ingmar
Sludge management in waste stabilization ponds (WSPs) is essential for safeguarding the system performance. Sludge accumulation patterns in WSPs are strongly influenced by the pond hydrodynamics. CFD modeling was applied to study the relation between velocity profiles and sludge deposition during 10 years of operation of the Ucubamba WSP in Cuenca (Ecuador). One tracer experiment was performed and three sludge accumulation scenarios based on bathymetric surveys were simulated. A residence time distribution (RTD) analysis illustrated the decrease of residence times due to sludge deposition. Sludge accumulation rates were calculated. The influence of flow pattern on the sludge deposition was studied, enabling better planning of future pond operation and desludging. © IWA Publishing 2012.
Differences Between Effective and Physical Roughness Parameter- A Headwater Mountain River Experiment
(IEEE, 2021) Cedillo Galarza, Juan Sebastian; Alvarado Martínez, Andrés Omar; Narea Cardenas, Katherine Estefania; Sánchez Cordero, Esteban Remigio; Timbe Castro, Luis Manuel; Samaniego Alvarado, Esteban Patricio
One-dimensional hydrodynamic models (HM) are widely used in the hydraulic modeling of rivers and channels. The result obtained with this type of model depends largely on correct estimation the roughness parameter. The value of the roughness parameter obtained through a HM calibration process differs from the one measured in the field. Hence, the objective of this research is focused on identifying the difference between physical and effective roughness for different morphologies present in Mountain Rivers. Physical roughness was indirectly measured with field data and Manning equation, while Effective roughness was found through GLUE experiments using water depth as validation data in one dimensional models in HEC RAS. Physical and effective roughness coefficients have shown differences depending on the morphology. In Cascade and Step-pool the physical roughness is higher than effective roughness, while in Plane-bed effective roughness is higher than physical roughness. The differences are attributed to the deviations that occur between the real conditions and the flow idealizations in an 1D - HD model. For any modelling application is important to research roughness values used previously and avoid formulations or tables which are based on field measurements.
Physics-Informed Neural Network water surface predictability for 1D steady-state open channel cases with different flow types and complex bed profile shapes
(2022) Alvarado Martínez, Andrés Omar; Cedillo Galarza, Juan Sebastian; Núñez, Ana Gabriela; Sánchez Cordero, Esteban Remigio; Timbe Castro, Luis Manuel; Samaniego Alvarado, Esteban Patricio
The behavior of many physical systems is described by means of differential equations. These equations are usually derived from balance principles and certain modelling assumptions. For realistic situations, the solution of the associated initial boundary value problems requires the use of some discretization technique, such as finite differences or finite volumes. This research tackles the numerical solution of a 1D differential equation to predict water surface profiles in a river, as well as to estimate the so-called roughness parameter. A very important concern when solving this differential equation is the ability of the numerical model to capture different flow regimes, given that hydraulic jumps are likely to be observed. To approximate the solution, Physics-Informed Neural Networks (PINN) are used. Benchmark cases with different bed profile shapes, which induce different flows types (supercritical, subcritical, and mixed) are tested first. Then a real mountain river morphology, the so-called Step-pool, is studied. PINN models were implemented in Tensor Flow using two neural networks. Different numbers of layers and neurons per hidden layer, as well as different activation functions (AF), were tried. The best performing model for each AF (according to the loss function) was compared with the solution of a standard finite difference discretization of the steady-state 1D model (HEC-RAS model). PINN models show good predictability of water surface profiles for slowly varying flow cases. For a rapid varying flow, the location and length of the hydraulic jump is captured, but it is not identical to the HEC-RAS model. The predictability of the tumbling flow in the Step-pool was good. In addition, the solution of the estimation of the roughness parameter (which is an inverse problem) using PINN shows the potential of this methodology to calibrate this parameter with limited cross-sectional data. PINN has shown potential for its application in open channel studies with complex bed profiles and different flow types, having in mind, however, that emphasis must be given to architecture selection.
Patterns of difference between physical and 1-D calibrated effective roughness parameters in mountain rivers
(2021) Timbe Castro, Luis Manuel; Alvarado Martínez, Andrés Omar; Samaniego Alvarado, Esteban Patricio; Cedillo Galarza, Juan Sebastián; Sánchez Cordero, Esteban Remigio
Due to the presence of boulders and different morphologies, mountain rivers contain various resistance sources. To correctly simulate river flow using 1-D hydrodynamic models, an accurate estimation of the flow resistance is required. In this article, a comparison between the physical roughness parameter (PRP) and effective roughness coefficient (ERC) is presented for three of the most typical morphological configurations in mountain rivers: cascade, step-pool, and plane-bed. The PRP and its variation were obtained through multiple measurements of field variables and an uncertainty analysis, while the ERC range was derived with a GLUE procedure implemented in HEC-RAS, a 1-D hydrodynamic model. In the GLUE experiments, two modes of the Representative Friction Slope Method (RFSM) between two cross-sections were tested, including the variation in the roughness parameter. The results revealed that the RFSM effect was limited to low flows in cascade and step-pool. Moreover, when HEC-RAS selected the RSFM, only acceptable results were presented for plane-bed. The difference between ERC and PRP depended on the flow magnitude and the morphology, and as shown in this study, when the flow increased, the ERC and PRP ranges approached each other and even overlapped in cascade and step-pool. This research aimed to improve the roughness value selection process in a 1-D model given the importance of this parameter in the predictability of the results. In addition, a comparison was presented between the results obtained with the numerical model and the values calculated with the field measurements.
Assessment of decentralized wastewater treatment systems in the rural area of Cuenca, Ecuador
(IWA PUBLISHING, 2017-03-01) Alvarado Martínez, Andrés Omar; Cisneros Ramos, Juan Fernando; Idrovo Murillo, Diego Benjamin; Sanchez Merchan, Esteban Andrés
The rapid urbanization of Cuenca, Ecuador, since about 1990 has led to efforts to build and operate decentralized domestic wastewater treatment systems in periurban and rural areas. The treatment efficiency of some of these is falling, however, and others are no longer working. ETAPA, the municipal institution in charge of water supply and sanitation, is evaluating them fully to identify common operating and maintenance difficulties, as well as deficiencies in design and/or construction. This paper presents an evaluation of the physical infrastructure and characterization of the treatment processes performed historically. The objective is to overcome the technical deficiencies and adopt a long-term, sustainable O&M plan.
Algal community analysis in a waste stabilisation pond
(ELSEVIER, 2014-12-01) Alvarado Martínez, Andrés Omar
Our knowledge on the algal community structure in waste stabilisation ponds is limited and it is unclear how physical-chemical changes affect the algal community structure and the treatment performance of waste stabilisation ponds. In the present paper we studied the spatial distribution of the algal community in a waste stabilisation pond in Cuenca (Ecuador) and found that the distribution was associated with the BOD concentration of the system. At the upstream end of the facultative pond where the BOD value is relatively high (74mgL-1), the community is dominated by motile algal species such as Euglena and Cryptophytes. More downstream, the algal community is more evenly distributed (G=0.26>0.18) and also non-motile species such as Chlorophytes and Chrysophytes are present. Throughout the ponds, the reduction of motile algal species was associated with the decrease in BOD concentration. The dominance of Chlorophyta, Chrysophyta and Euglenophyta was highly associated with BOD concentration. Furthermore, it was concluded that the algal abundance (45541cellsmL-1), diversity (D=0.85), evenness (G=0.26) and richness (20.97) of the community in the maturation pond were higher than those of the facultative pond. The results of this research are valuable for a better understanding of the algae-based processes in waste stabilisation ponds.
Modified first stage of french vertical flow constructed wetlands for wastewater treatment in highlands: start-up of the system
(Springer Nature, 2021) García Zumalacarregui, Jorge Alejandro; Arevalo Durazno, Maria Belen; Narvaez Torres, Andrea Carolina; Alvarado Martínez, Andrés Omar
Worldwide, decentralized sanitation systems represent an appropriate, sustainable, simpler, and cost-effective option for communities where conventional wastewater treatment technologies have failed by not considering the inherent characteristics of those societies. In this research, the start-up phase of a cost-effective decentralized sanitation technology is presented: The modified first stage of French vertical flow constructed wetlands for raw wastewater treatment. In the three pilot units comprising the modified first stage, Lolium perenne was the vegetation planted and showed great adaptability to the climatic conditions of the highlands and wastewater characteristics from a combined sewerage. In order to evaluate the performance of the system, in situ parameters were measured and physical chemical analyses were performed from samples of the three units. Efficiencies over 45% were obtained for the removal of organic matter and total suspended solids. The pilots demonstrated that the first stage of French vertical flow constructed wetlands is robust and reliable from their start-up period and treating hydraulic overloads.
Validación de modelos computacionales de flujo dinámico con pruebas de trazadores en lagunas de gran escala
(2011) Cedillo Galarza, Juan Sebastián; Matailo Quituisaca, María Magdalena; Alvarado Martínez, Andrés Omar; Alvarado Martínez, Andrés Omar
Adsorption of estradiol by natural clays and Daphnia magna as biological filter in an aqueous mixture with emerging contaminants
(2021) Cipriani Ávila, Eva Isabel; Capparelli, Mariana V.; Jara Negrete, Eliza Nuit; Alvarado Martínez, Andrés Omar; Cisneros Ramos, Juan Fernando; Tripaldi, Piercosimo; Perez Gonzalez, Bolivar Andres; Pinos Vélez, Verónica Patricia
Among emerging pollutants, endocrine disruptors such as estradiol are of most concern. Conventional water treatment technologies are not capable of removing this compound from water. This study aims to assess a method that combines physicochemical and biological strategies to eliminate estradiol even when there are other compounds present in the water matrix. Na-montmorillonite, Ca-montmorillonite and zeolite were used to remove estradiol in a medium with sulfamethoxazole, triclosan, and nicotine using a Plackett–Burman experimental design; each treatment was followed by biological filtration with Daphnia magna. Results showed between 40 to 92% estradiol adsorption in clays; no other compounds present in the mixture were adsorbed. The most significant factors for estradiol adsorption were the presence of nicotine and triclosan which favored the adsorption, the use of Ca-montmorillonite, Zeolite, and time did not favor the adsorption of estradiol. After the physicochemical treatment, Daphnia magna was able to remove between 0–93% of the remaining estradiol. The combination of adsorption and biological filtration in optimal conditions allowed the removal of 98% of the initial estradiol concentration.
Development of an automated tracer testing system for UASB laboratory-scale reactors
(2021) Cisneros Ramos, Juan Fernando; Nopens, Ingmar; Pinos Vélez, Verónica Patricia; Peláez Samaniego, Manuel Raúl; Alvarado Martínez, Andrés Omar
Residence time distribution (RTD) curves play an essential role in the hydraulic characterization of reactors. Current approaches for obtaining RTD curves in laboratory-scale reactors are time-consuming and subject to large errors. Thus, automated systems to obtain RTD curves in laboratory-scale reactors are of great interest for reducing experimental errors due to human interaction, minimizing experimentation costs, and continuously obtaining experimental data. An automated system for obtaining RTD curves in laboratory-scale reactors was designed, built, and tested in this work. During the tests conducted in a cylindrical upflow anaerobic sludge blanket (UASB) reactor, the system worked properly using the stimulus–response pulse technique with sodium chloride as a tracer. Four main factors were found to affect the representativeness of the RTD curves: flow stabilization time, test water conductivity, temperature, and surface tension. A discussion on these factors and the corresponding solutions is presented. The RTD curves of the UASB reactor are left-skewed with a typical tank reactor’s flow shape with channeling and dead zones. A transitory flow behavior was evidenced in the reactor, which indicates the influence of internal turbulent flow structures. The system proposed herein is expected to help study the hydraulics of reactors using laboratory-scale models more efficiently