ABSTRACT
Solutions to the diffusion equations in geometry of three or more layers are rarely available. These problems may arise in layered soil systems. Multilayered composites may also be used as capping material over contaminated sediment. This chapter presents the solutions giving the mobile phase concentration profile and surface flux rate for a system consisting of a composite of three layers of different properties. It analyzes both cases where surface mass transfer and contaminant decay are significant and insignificant. The chapter discusses the numerical evaluation of the solution. The system equations were solved using a separation of variables technique. The chapter outlines the solution method. A multilayer composite model may also be used to model contaminant vapor transport in a sediment column with a low moisture content profile. Different layers can represent various moisture content regimes, which consequently have different contaminant transport properties. Both calculations for the concentration and surface flux require the sum of an infinite series of terms.
