Mathematical Modelling of Wastewater Treatment in Oxidation Pond

2019 ◽  
Vol 16 (11) ◽  
pp. 4455-4460
Author(s):  
Nurul Nadiah Muhammad ◽  
Dennis Ling Chuan Ching ◽  
Amir Syafiq Syamin Syah Amir Hamzah

Oxidation pond also known as shallow ponds designed to treat wastewater through the interaction of sunlight, bacteria and algae. In this research, wastewater treatment model was developed to study the effect of pH towards, COD, DO and PSB. Using the process rate of breakdown of organic and inorganic substance, mass transfer and oxygen and the growth of bacteria as conditions, the advection-diffusion-reaction equations are solved using Crank Nicolson method. Comparisons were with existing data to verify the model and the similarity of dynamical behaviour.

2021 ◽  
Vol 82 (1-2) ◽  
Author(s):  
Christian Engwer ◽  
Michael Wenske

AbstractGlioblastoma Multiforme is a malignant brain tumor with poor prognosis. There have been numerous attempts to model the invasion of tumorous glioma cells via partial differential equations in the form of advection–diffusion–reaction equations. The patient-wise parametrization of these models, and their validation via experimental data has been found to be difficult, as time sequence measurements are mostly missing. Also the clinical interest lies in the actual (invisible) tumor extent for a particular MRI/DTI scan and not in a predictive estimate. Therefore we propose a stationalized approach to estimate the extent of glioblastoma (GBM) invasion at the time of a given MRI/DTI scan. The underlying dynamics can be derived from an instationary GBM model, falling into the wide class of advection-diffusion-reaction equations. The stationalization is introduced via an analytic solution of the Fisher-KPP equation, the simplest model in the considered model class. We investigate the applicability in 1D and 2D, in the presence of inhomogeneous diffusion coefficients and on a real 3D DTI-dataset.


2019 ◽  
Vol 22 (4) ◽  
pp. 918-944 ◽  
Author(s):  
William McLean ◽  
Kassem Mustapha ◽  
Raed Ali ◽  
Omar Knio

Abstract We establish the well-posedness of an initial-boundary value problem for a general class of linear time-fractional, advection-diffusion-reaction equations, allowing space- and time-dependent coefficients as well as initial data that may have low regularity. Our analysis relies on novel energy methods in combination with a fractional Gronwall inequality and properties of fractional integrals.


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