Summary. The calibration of a model refers to the process by which

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We study a one-dimensional multi-species system of dispersive-advective contaminant transport equations coupled by nonlinear biological (kinetic reactions) and physical (adsorption) processes. To deal with the nonlinearities and the coupling, and to avoid additional computational costs, we propose a linearization technique based on first-order Taylor's series expansions. A stabilized finite element in space, combined with an Euler implicit finite difference discretization in time, is used to approximate the dispersive-advective transport problem. Three computational tests are performed with different boundary conditions, retardation factors and kinetic parameters for a nonlinear reactive multi-species transport model. The proposed methodology is shown to be accurate and decrease computational costs in the numerical implementation of nonlinear reactive transport problems.

ResumoPropomos reduzir a complexidade existente nos modelos não-lineares BIOMOC e ASM1, aplicando a primeira ordem da expansão em série de Taylor nos termos cujos processos reativos são não-lineares. Uma das vantagens dos modelos linearizados é a conservação das variáveis do modelo não linear. Porém a característica principal desta metodologia refere-se ao tempo computacional obtido nas simulações numéricas, que é muito menor do que o referente aos resultados do modelo não-linear. Apresentamos resultados numéricos que demonstram a eficiência, precisão e robustez, da técnica proposta em casos conhecidos da literatura, utilizando o método semi-discreto de elementos finitos. Palavras-chave: Modelos não lineares. Método de elementos finitos. ASM1. AbstractIt is proposed to reduce the complexity existing in non-linear BIOMOC and ASM1 models using Taylor's first-order series expansion in the terms whose reactive processes are non-linear. One of the advantages of linear models is the conservation of non-linear model variables. However, the main characteristic of this methodology refers to the computational time obtained in the numeral simulations, which is much shorter than that concerning the non-linear model results. Numerical results are presented, showing the efficiency, precision and solidity of the proposed technique in well-known cases in the literature, using the semi-discrete method of finite elements.