Revistas
Revista:
WATER RESEARCH
ISSN:
0043-1354
Año:
2021
Vol.:
203
Págs.:
117477
Revista:
WATER RESEARCH
ISSN:
0043-1354
Año:
2021
Vol.:
206
Págs.:
117779
Ammonia ion removal and recovery via an ion-exchange process using zeolites is a promising alternative to traditional biological treatments. The analysis of its efficiency is not straightforward as it depends on various factors, such as the cation exchange capacity of the zeolite, amount of zeolite available, initial ammonia concentration, contact time, ammonia speciation depending on pH or the presence of competing ions. Mathematical modelling and simulation tools are very useful to analyse the effect of different operational conditions on the efficiency and optimal operation of the process. This paper experimentally analyses the effect that the presence of competing ions has on the efficiency of ammonia removal. This experimental work has shown a reduction of around 21% of ammonia removal efficiency in the presence of competing ions. The main contribution of this paper is the development new mathematical model able to describe the ion-exchange process in the presence of competing ions. The mathematical model developed is able to analyse the performance of the IEX process under different empty bed contact times, influent loads, pH and concentrations of competing ions. The capability of the model to reproduce real data has been proven comparing the experimental and simulation results. Finally, an exploration by simulation has been undertaken to show the potential of the mathematical model developed.
Revista:
WATER RESEARCH
ISSN:
0043-1354
Año:
2021
Vol.:
200
Págs.:
117242
The effect of mixing in the modelling of processes based on mass transfer phenomena is commonly ignored in wastewater treatment industry. In this contribution, the effect of the average shear rate in the nucleation and growth rates of struvite is analyzed by combining experimental data with simulation results obtained with a previously presented mass-based discretized population balance model. According to the obtained results, the effect of the average shear rate is identifiable for the selected data and mechanisms. Therefore, it should be considered when a detailed modelling of the process is needed. Consequently, in this contribution, the average shear rate has been decoupled from the kinetic constants. In addition, kinetic rates where it is explicitly included as a power law function have been proposed. The exponents in these power law functions for the primary homogeneous nucleation and growth are 1.3 and 0.3, respectively. Considering shear rate effects allowed to see in the simulation outputs experimentally observed effects: a faster pH decay and smaller particle distribution for increasing mixing intensities. (c) 2021 Elsevier Ltd. All rights reserved.
Revista:
WATER RESEARCH
ISSN:
0043-1354
Año:
2019
Vol.:
155
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.
Revista:
WATER RESEARCH
ISSN:
0043-1354
Año:
2019
Vol.:
153
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:
Amaral, A. (Autor de correspondencia); Gillot, S.; Garrido-Baserba, M. ; et al.
Revista:
WATER SCIENCE AND TECHNOLOGY
ISSN:
0273-1223
Año:
2019
Vol.:
80
N°:
4
Págs.:
607 - 619
Gas-liquid mass transfer in wastewater treatment processes has received considerable attention over the last decades from both academia and industry. Indeed, improvements in modelling gas-liquid mass transfer can bring huge benefits in terms of reaction rates, plant energy expenditure, acid-base equilibria and greenhouse gas emissions. Despite these efforts, there is still no universally valid correlation between the design and operating parameters of a wastewater treatment plant and the gas-liquid mass transfer coefficients. That is why the current practice for oxygen mass transfer modelling is to apply overly simplified models, which come with multiple assumptions that are not valid for most applications. To deal with these complexities, correction factors were introduced over time. The most uncertain of them is the alpha-factor. To build fundamental gas-liquid mass transfer knowledge more advanced modelling paradigms have been applied more recently. Yet these come with a high level of complexity making them impractical for rapid process design and optimisation in an industrial setting. However, the knowledge gained from these more advanced models can help in improving the way the alpha-factor and thus gas-liquid mass transfer coefficient should be applied. That is why the presented work aims at clarifying the current state-of-the-art in gas-liquid mass transfer modelling of oxygen and other gases, but also to direct academic research efforts towards the needs of the industrial practitioners.
Revista:
WATER RESEARCH
ISSN:
0043-1354
Año:
2018
Vol.:
129
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.
Revista:
WATER SCIENCE AND TECHNOLOGY
ISSN:
0273-1223
Año:
2017
Vol.:
75
N°:
3
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.
Revista:
WATER RESEARCH
ISSN:
0043-1354
Año:
2017
Vol.:
118
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.
Revista:
WATER RESEARCH
ISSN:
0043-1354
Año:
2015
Vol.:
74
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.
Revista:
TECNOAQUA
ISSN:
2340-2091
Año:
2014
Vol.:
9
Págs.:
64 - 72
Revista:
WATER RESEARCH
ISSN:
0043-1354
Año:
2014
Vol.:
60
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.
Revista:
WATER SCIENCE AND TECHNOLOGY
ISSN:
0273-1223
Año:
2012
Vol.:
65
N°:
11
Págs.:
1929 - 1938
The increasing costs associated with water supply and the disposal of wastewater has stimulated industries to seek more efficient water management systems. Mathematical modelling and simulation can be a very valuable tool for the study of the multiple alternatives available whilst assessing optimum solutions for water management in industry. This study introduces a new steady state model library able to reproduce industrial water circuits. It has been implemented in a novel software framework for the representation, simulation and optimization of industrial water networks. A water circuit representing a paper mill has been modelled and simulated showing the capability to reproduce real case studies. Alternative scenarios for the water network have also been tested to assess the capability of the models to optimize water circuits minimizing total cost.