Nuestros investigadores

Eduardo José Ayesa Iturrate

Publicaciones científicas más recientes (desde 2010)

Autores: Elduayen Echave, Beñat (Autor de correspondencia); Lizarralde Aguirrezabal, Izaro; Sánchez Larraona, Gorka; et al.
ISSN 0043-1354  Vol. 155  2019  págs. 26 - 41
Mathematical models describing precipitation processes in one step need to be upgraded. Particle size distribution is a crucial variable and its inclusion in the modelling libraries is necessary if the technology wants to be optimized through simulation. With this objective, a mass based population balance model is presented in this contribution. The model has been constructed using a stoichiometric matrix and a kinetic vector and using mass as the internal coordinate, as it is usually done in wastewater treatment modelling. Identifiability of the parameters of the model was evaluated using a sensitivity and a collinearity analysis for six simulation case studies of struvite precipitation. In addition, parameters in the model were calibrated to represent data from two batch tests in the laboratory. The results of the analysis showed that the identifiability of the parameters depends on the available experimental data and explored scenarios. Identifiability of the parameters could be the reason behind the shifting parameter values describing mechanisms of precipitation in the literature. This contribution helps to understand the possibilities and limitations that the population balance model approach offer.
Autores: Lizarralde Aguirrezabal, Izaro (Autor de correspondencia); Fernández Arevalo, Tamara; Manas, A. ; et al.
ISSN 0043-1354  Vol. 153  2019  págs. 39 - 52
Phosphorus has been considered as a pollutant to be removed from the wastewater. In the last years, however, it has been considered a valuable asset that needs to be recovered due to its shortage in nature. The study of optimum phosphorus management in wastewater treatment plants is not straightforward, due to the complexity of technologies and configurations that may be applied for phosphorus removal and recovery. In this context, plant-wide mathematical modelling and simulation tools are very useful for carrying out these studies. This paper introduces a study carried out at the Sur WWTP (Madrid) to assess optimum phosphorus management strategies based on the PWM. The mathematical model made it possible to describe the phosphorus flux and its characterization throughout the plant. Finally, an exploration by simulation with WEST (TM) was carried out to analyse different plant configurations and different operational strategies to optimize phosphorus management strategies in the Sur WWTP.
Autores: Lizarralde Aguirrezabal, Izaro (Autor de correspondencia); Fernández Arevalo, Tamara; Beltrán Calaff, Sergio; et al.
ISSN 0043-1354  Vol. 129  2018  págs. 305 - 318
This paper introduces a new mathematical model built under the PC-PWM methodology to describe the aeration process in a full-scale WWTP. This methodology enables a systematic and rigorous incorporation of chemical and physico-chemical transformations into biochemical process models, particularly for the description of liquid-gas transfer to describe the aeration process. The mathematical model constructed is able to reproduce biological COD and nitrogen removal, liquid-gas transfer and chemical reactions. The capability of the model to describe the liquid-gas mass transfer has been tested by comparing simulated and experimental results in a full-scale WWTP. Finally, an exploration by simulation has been undertaken to show the potential of the mathematical model. (C) 2017 Elsevier Ltd. All rights reserved.
Autores: Fernández Arevalo, Tamara; Lizarralde Aguirrezabal, Izaro; Maiza, M.; et al.
ISSN 0273-1223  Vol. 75  Nº 3  2017  págs. 518 - 529
Given the shift in perception of wastewater treatment plants as water resource recovery facilities, conventional mathematical models need to be updated. The resource recovery perspective should be applied to new processes, technologies and plant layouts. The number and level of models proposed to date give an overview of the complexity of the new plant configurations and provides a wide range of possibilities and process combinations in order to construct plant layouts. This diversity makes the development of standard, modular and flexible tools and model libraries that allow the incorporation of new processes and components in a straightforward way a necessity. In this regard, the plant-wide modelling (PWM) library is a complete model library that includes conventional and advanced technologies and that allows economic and energetic analyses to be carried out in a holistic way. This paper shows the fundamentals of this PWM library that is built upon the above-mentioned premises and the application of the PWM library in three different full-scale case studies.
Autores: Fernández Arevalo, Tamara; Lizarralde Aguirrezabal, Izaro; Fdz-Polanco, F.; et al.
ISSN 0043-1354  Vol. 118  2017  págs. 272 - 288
The growing development of technologies and processes for resource treatment and recovery is offering endless possibilities for creating new plant-wide configurations or modifying existing ones. However, the configurations¿ complexity, the interrelation between technologies and the influent characteristics turn decision-making into a complex or unobvious process. In this frame, the Plant-Wide Modelling (PWM) library presented in this paper allows a thorough, comprehensive and refined analysis of different plant configurations that are basic aspects in decision-making from an energy and resource recovery perspective. In order to demonstrate the potential of the library and the need to run simulation analyses, this paper carries out a comparative analysis of WWTPs, from a techno-economic point of view. The selected layouts were (1) a conventional WWTP based on a modified version of the Benchmark Simulation Model No. 2, (2) an upgraded or retrofitted WWTP, and (3) a new Wastewater Resource Recovery Facilities (WRRF) concept denominated as C/N/P decoupling WWTP. The study was based on a preliminary analysis of the organic matter and nutrient energy use and recovery options, a comprehensive mass and energy flux distribution analysis in each configuration in order to compare and identify areas for improvement, and a cost analysis of each plant for different influent COD/TN/TP ratios. Analysing the plants from a standpoint of resources and energy utilization, a low utilization of the energy content of the components could be observed in all configurations. In the conventional plant, the COD used to produce biogas was around 29%, the upgraded plant was around 36%, and 34% in the C/N/P decoupling WWTP. With regard to the self-sufficiency of plants, achieving self-sufficiency was not possible in the conventional plant, in the upgraded plant it depended on the influent C/N ratio, and in the C/N/P decoupling WWTP layout self-sufficiency was feasible for almost all influents, especially at high COD concentrations. The plant layouts proposed in this paper are just a sample of the possibilities offered by current technologies. Even so, the library presented here is generic and can be used to construct any other plant layout, provided that a model is available.
Autores: Lizarralde Aguirrezabal, Izaro; Fernández Arevalo, Tamara; Brouckaert, C; et al.
ISSN 0043-1354  Vol. 74  2015  págs. 239 - 256
This paper introduces a new general methodology for incorporating physico-chemical and chemical transformations into multi-phase wastewater treatment process models in a systematic and rigorous way under a Plant-Wide modelling (PWM) framework. The methodology presented in this paper requires the selection of the relevant biochemical, chemical and physico-chemical transformations taking place and the definition of the mass transport for the co-existing phases. As an example a mathematical model has been constructed to describe a system for biological COD, nitrogen and phosphorus removal, liquid gas transfer, precipitation processes, and chemical reactions. The capability of the model has been tested by comparing simulated and experimental results for a nutrient removal system with sludge digestion. Finally, a scenario analysis has been undertaken to show the potential of the obtained mathematical model to study phosphorus recovery. (C) 2015 Elsevier Ltd. All rights reserved.
Autores: Fernández Arevalo, Tamara; Lizarralde Aguirrezabal, Izaro; Grau Gumbau, Paloma; et al.
ISSN 0043-1354  Vol. 60  2014  págs. 141 - 155
This paper presents a new modelling methodology for dynamically predicting the heat produced or consumed in the transformations of any biological reactor using Hess's law. Starting from a complete description of model components stoichiometry and formation enthalpies, the proposed modelling methodology has integrated successfully the simultaneous calculation of both the conventional mass balances and the enthalpy change of reaction in an expandable multi-phase matrix structure, which facilitates a detailed prediction of the main heat fluxes in the biochemical reactors. The methodology has been implemented in a plant-wide modelling methodology in order to facilitate the dynamic description of mass and heat throughout the plant. After validation with literature data, as illustrative examples of the capability of the methodology, two case studies have been described. In the first one, a predenitrification-nitrification dynamic process has been analysed, with the aim of demonstrating the easy integration of the methodology in any system. In the second case study, the simulation of a thermal model for an ATAD has shown the potential of the proposed methodology for analysing the effect of ventilation and influent characterization. (C) 2014 Elsevier Ltd. All rights reserved.
Autores: Dalmau, M.; Rodriguez-Roda, I.; Ayesa Iturrate, Eduardo José; et al.
ISSN 1385-8947  Vol. 217  2013  págs. 174 - 184
The combination of simulation studies and expert knowledge allows the development of a decision tree for the integrated operation of nutrient removal as well as filtration processes in membrane bioreactors (MBRs). In order to do it, a model-based methodology, including model development and use of system analysis tools, was followed to identify the best operational strategies for good filtration performance and efficient biological nutrient removal at lower costs in a University Cape Town (UCT)-MBR pilot plant. Activated sludge no. 2 and a series resistance model were used to simulate the biological and filtration processes, respectively. A sensitivity analysis was carried out for the identification of the most sensitive operational parameters, and then, their best setpoint ranges/values were identified through a scenario analysis. Simulation results were supplemented with expert process knowledge to overcome the current limitations of biological and filtration models. The results were organized in the form of a decision tree. The most sensitive parameters, and thus the first branch to explore, were operational parameters related to the filtration processes (i.e. flux and relaxation time). Based on expert knowledge, membrane-air scour was the following control action to check. Then, the decision tree evaluates the biological nutrient removal processes and modifies the necessary operational parameters, ranked according to their sensitivity. The most sensitive were aerobic and membrane aeration, aerobic and anoxic recirculations and carbon dosage. The last branch takes into account the operational cost, directly related to aeration and carbon addition. (C) 2012 Elsevier B.V. All rights reserved.
Autores: Maiza Galparsoro, Mikel; Bengoechea García, Asier; Grau Gumbau, Paloma; et al.
ISSN 0273-1223  Vol. 68  Nº 2  2013  págs. 296 - 302
This paper summarizes part of the research work carried out in the Add Control project, which proposes an extension of the wastewater treatment plant (WWTP) models and modelling architectures used in traditional WWTP simulation tools, addressing, in addition to the classical mass transformations (transport, physico-chemical phenomena, biological reactions), all the instrumentation, actuation and automation & control components (sensors, actuators, controllers), considering their real behaviour (signal delays, noise, failures and power consumption of actuators). Its ultimate objective is to allow a rapid transition from the simulation of the control strategy to its implementation at full-scale plants. Thus, this paper presents the application of the Add Control simulation platform for the design and implementation of new control strategies at the WWTP of Mekolalde.
Autores: Beltrán Calaff, Sergio; Maiza Galparsoro, Mikel; De La Sota, A.; et al.
ISSN 0273-1223  Vol. 66  Nº 2  2012  págs. 314-320
The lack of appropriate data management tools is presently a limiting factor for a broader implementation and a more efficient use of sensors and analysers, monitoring systems and process controllers in wastewater treatment plants (WWTPs). This paper presents a technical solution for advanced data management of a full-scale WWTP. The solution is based on an efficient and intelligent use of the plant data by a standard centralisation of the heterogeneous data acquired from different sources, effective data processing to extract adequate information, and a straightforward connection to other emerging tools focused on the operational optimisation of the plant such as advanced monitoring and control or dynamic simulators. A pilot study of the advanced data manager tool was designed and implemented in the Galindo-Bilbao WWTP. The results of the pilot study showed its potential for agile and intelligent plant data management by generating new enriched information combining data from different plant sources, facilitating the connection of operational support systems, and developing automatic plots and trends of simulated results and actual data for plant performance and diagnosis.
Autores: Brockmann, D.; Steyer, J.P.; De Keyser, W.; et al.
ISSN 1569-1705  Vol. 10  Nº 1  2011  págs. 3 - 7
Instrumentation, control, and automation (ICA) in wastewater treatment enables the improvement of treatment plant performance without structural modifications of the plant. Even for wastewater treatment plants (WWTPs) meeting all criteria with respect to effluent concentrations and sludge disposal, ICA can be of interest as it can help to reduce energy consumption and operating costs of the plant. Simulations are a useful and cost-effective tool for designing and evaluating different control strategies. Simulation strategies developed with existing WWTP-specific simulation packages are based on ideal sensor and actuator behavior because signal noise and potential sensor and actuator failures are not considered. Real sensor and actuator behavior including failures, however, needs to be accounted for to ensure robust controller performance despite disturbances in sensor and actuator behavior. The ADD CONTROL project aims to design, implement, and validate a new simulation tool that allows for designing and testing "practical" control solutions. A multi-layer modeling architecture is proposed for the simulation tool to represent the hierarchical architecture for automation and control in full-scale WWTPs, and to separate mathematical modeling of components related to the treatment process from components describing instrumentation and actuation devices, and components related to automation and control. The developed simulation tool is implemented based on the TORNADO framework for modeling and virtual experimentation and the WEST(A (R)) product suite.
Autores: de Gracia, M.; Grau Gumbau, Paloma; Ayesa Iturrate, Eduardo José; et al.
ISSN 0273-1223  Vol. 64  Nº 3  2011  págs. 557 - 567
This paper presents the characterisation procedure of different types of sludge generated in a wastewater treatment plant to be reproduced in a mathematical model of the sludge digestion process. The automatic calibration method used is based on an optimisation problem and uses a set of mathematical equations related to the a priori knowledge of the sludge composition, the experimental measurements applied to the real sludge, and the definition of the model components. In this work, the potential of the characterisation methodology is shown by means of a real example, taking into account that sludge is a very complex matter to characterise and that the models for digestion also have a considerable number of model components. The results obtained suit both the previously reported characteristics of the primary, secondary and mixed sludge, and the experimental measurements specially done for this work. These three types of sludge have been successfully characterised to be used in complex mathematical models.
Autores: Cardona, C.M.; Martin, C.; Salterain Ezquerra, Antonio; et al.
ISSN 1364-8152  Vol. 26  Nº 7  2011  págs. 973 - 979
This paper presents CalHidra 3.0, a new software package developed for dynamic simulation of water quality in rivers. CalHidra 3.0 combines a 1-D hydrodynamic model based on Saint Venant equations, a transport sub-model that incorporates the advection-dispersion terms, and a simplified version of the River Water Quality Model 1 (RWQM1) for the biochemical transformations. This advanced biochemical sub-model allows the dynamic simulation of the bacterial populations in rivers, making possible the simulation of the river acclimatisation to changes of pollutant load or environmental conditions. The software also includes new tools for a Monte Carlo based Bayesian calibration of the unknown model parameters. CalHidra 3.0 is implemented based on the Component Object Model (COM) programming paradigm and uses the Windows graphical environment. Three case studies illustrate the possibilities of the CalHidra 3.0 software. (C) 2011 Elsevier Ltd. All rights reserved.
Autores: Martin, C.; Ayesa Iturrate, Eduardo José
ISSN 0304-3800  Vol. 221  Nº 22  2010  págs. 2656 - 2667
This paper proposes an Integrated Monte Carlo Methodology (IMCM) to solve the parameter estimation problem in water quality models. The methodology is based on Bayesian approach and Markov Chain Monte Carlo techniques and it operates by means of four modules: Markov Chain Monte Carlo (MCMC), Moving Feasible Ranges (MFR), Statistical Analysis of the Joint Posterior Distribution (SAD) and Uncertainty Propagation Analysis (UPA). The main innovation of the new proposal lies in the combination of MCMC and MFR modules which provides the joint posterior distribution of the calibrated parameters following the classical Bayesian approach. While MCMC module, based on Shuffled Complex Evolution Metropolis (SCEM-UA) algorithm, is specially designed to sample complex joint posterior shapes within certain parameter ranges, the MFR readjusts these ranges until the coverage of the feasible parameter space is guaranteed. Once the joint posterior distribution is properly defined, the SAD provides the parameter statistics and the UPA performs an analysis of the uncertainty propagation through the model. The possibilities of the new proposal have been tested on the basis of a simple model featuring different activated sludge batch experiments. IMCM has been implemented in Matlab and it is prepared to be easily connected to any software package. (C) 2010 Elsevier B.V. All rights reserved.
Autores: Elduayen Echave, Beñat; Ochoa de Eribe, A.; Lizarralde Aguirrezabal, Izaro; et al.
Libro:  Frontiers in Wastewater Treatment and Modelling. Lecture Notes in Civil Engineering
Vol. 4  2017  págs. 614 - 621
Struvite precipitation has raised as a promising solution to recover phosphorous in wastewater treatment plants (WWTP). Struvite is a fertilizer that varies its performance depending on its size. This shows the need to upgrade one-step classic kinetic precipitation models by new frameworks as the Population Balance Model (PBM). In this abstract a mass-based Discretized Population Balance Model (DPBM) used to predict struvite precipitation is presented. The model includes primary nucleation, growth and aggregation mechanisms as a function of supersaturation index and kinetic parameters. Main advantage of the mass-based definition is that mass continuity is guaranteed and that it is fully compatible with other chemical and physicochemical reactions. A sensitivity analysis performed reveals exponents of nucleation and growth as the most relevant parameters in the pH evolution during precipitation and final Particle Size Distribution (PSD). Experimental data was used to calibrate the model employing Bayesian Inference. Selected values of the parameters showed good agreement with reality.