Search results for "Mathematical Modelling"
showing 10 items of 59 documents
A mathematical approach to predict the solids concentration in anaerobic membrane bioreactos (AnMBR): Evaluation of the volatile solids solubilization
2020
[EN] Anaerobic Membrane Bioreactors (AnMBR) are gaining attention as a suitable approach for sustainable low-strength wastewater treatment, as they bring together the advantages of both anaerobic treatments and membrane bioreactors. However, increasing the sludge retention time (SRT) necessary to favor hydrolysis increases the suspended solids concentration potentially leading to decreased permeate flux. Therefore, the availability of a mathematical approach to predict the solids concentration within an AnMBR can be very useful. In this work, a mathematical model describing the volatile solids concentration within the reactor as a function of the operating parameters and the influent charac…
On the measurement of local gas hold-up and interfacial area in gas–liquid contactors via light sheet and image analysis
2010
Abstract Particle image velocimetry techniques coupled with advanced image processing tools are receiving an increasing interest for measuring flow quantities and local bubble-size distributions in gas–liquid contactors. Aim of this work is that of providing a numerical procedure able to reconstruct local gas hold-up and specific interfacial area from images obtained by laser sheet illumination. A correction for measured quantities accounting for laser sheet thickness is proposed and tested by means of Monte Carlo simulations. The algorithms proposed are robust and independent of any measured parameters of the actual bubble size distribution.
Modelling biological and chemically induced precipitation of calcium phosphate in enhanced biological phosphorus removal systems
2011
The biologically induced precipitation processes can be important in wastewater treatment, in particular treating raw wastewater with high calcium concentration combined with Enhanced Biological Phosphorus Removal. Currently, there is little information and experience in modelling jointly biological and chemical processes. This paper presents a calcium phosphate precipitation model and its inclusion in the Activated Sludge Model No 2d (ASM2d). The proposed precipitation model considers that aqueous phase reactions quickly achieve the chemical equilibrium and that aqueous-solid change is kinetically governed. The model was calibrated using data from four experiments in a Sequencing Batch Rea…
Receiving water quality assessment: comparison between simplified and detailed integrated urban modelling approaches
2010
Urban water quality management often requires use of numerical models allowing the evaluation of the cause–effect relationship between the input(s) (i.e. rainfall, pollutant concentrations on catchment surface and in sewer system) and the resulting water quality response. The conventional approach to the system (i.e. sewer system, wastewater treatment plant and receiving water body), considering each component separately, does not enable optimisation of the whole system. However, recent gains in understanding and modelling make it possible to represent the system as a whole and optimise its overall performance. Indeed, integrated urban drainage modelling is of growing interest for tools to …
Coloring Linear Algebra
2016
[EN] We present an example of how we can introduce basic concepts on Linear Algebra in a first course of an Engineering School. We use the RGB pattern color which allows us to decompose a color into three primary colors (namely, red, green, blue). By using this model we give a natural connexion between the additivity of the color decomposition and the notions on linear algebra (as vector space, linear combination and convex linear span of vectors). To visualize these connexions we use Geogebra.
Global sensitivity analysis for micropollutant modeling by means of an urban integrated approach
2015
The paper presents the sensitivity analysis of an integrated urban water quality system by means of the global sensitivity analysis (GSA). Specifically, an home-made integrated model developed in previous studies has been modified in order to include the micropollutant assessment (namely, sulfamethoxazole - SMX). The model is able to estimate also the interactions between the three components of the system: sewer system (SS), wastewater treatment plant (WWTP) and the receiving water body (RWB). The analysis has been applied to an experimental catchment nearby Palermo (Italy): the Nocella catchment. Five scenarios each characterized by different combinations of sub-systems (i.e., SS, WWTP an…
Greenhouse gas emissions from integrated urban drainage systems: where do we stand?
2017
Integrated urban drainage systems (IUDS) (i.e., sewer systems, wastewater treatment plants and receiving water bodies) contribute to climate change being sources of greenhouse gas emissions (GHG). This paper, produced by the International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, reviews the state-of-the-art and the recently developed modelling tools used to understand and manage GHG emissions from IUDS. Further, open problems and research gaps are discussed, while proposing a framework for handling GHG from IUDS. The literature review reveals that there is a need to strengthen and partially adequate already available mathematical mo…
THE IDENTIFIABILITY ANALYSIS FOR SETTING UP MEASURING CAMPAIGNS FOR INTEGRATED WATER QUALITY MODELLING
2010
Identifiability analysis enables one the quantification of the number of model parameters that can be assessed by calibration with respect to a data set. Such a methodology is based on the appraisal of sensitivity coefficients of the model parameters by means of Monte Carlo runs. By employing the Fisher Information Matrix, the methodology is able to gain insights with respect to the number of model parameters that can be reliably assessed. The paper presents a study where identifiability analysis is used as a tool for the setting up of measuring campaigns for integrated water quality modelling. The analysis has been applied to a real case study characterized by a partially urbanized catchme…
Mathematical modelling of biogas from municipal solid waste landfil
2016
Sanitary landfills for municipal solid wastes can be considered as large biological reactors where the organic fraction of municipal solid waste undergoes anaerobic digestion producing gas and liquid emissions. Leachate production from municipal sanitary landfills is currently recognized as a major environmental burden associated with municipal solid waste management and it may be responsible for local pollution of groundwater and soil. Moreover, the fate of the organic compounds within the landfill body is of primary importance since it directly influences the production of landfill gas. The aim of the paper is to propose an integrated mathematical model able to simulate, on one hand, the …
Application of Mathematical Models in Analysis of Heat Losses in the Buildings
2006
Physical model of heat balance for separate living room is discussed, which allows to analyse the distributions of the flow of air and temperature depending on the physical conditions and geometry. The model enables to choose the optimal surface area of building elements and their properties in order to decrease the heat losses and improve the conditions of thermal comfort. Room with bounding constructions and real dimensions is modelled that helps to understand the peculiarities of heat transfer process in the room as well as distribution of various characteristic quantities and their dependence on the different conditions. Multiple parameters are varied in 2D calculations and their influe…