(588d) Steady State Design Model of Concentrations and Fluxes in a Sediment Cap

Remediation of contaminated sediments is one of the most challenging problems in environmental engineering today. One of the few effective means of reducing exposure and risk to contaminated sediments is through the use of capping with clean media. Effective design of a cap to isolate contaminated sediments requires a model capable of describing the chemical fate and transport processes that take place within the cap. The standard tool for cap design is an analytical model that describes the transient migration of a contaminant within a chemical isolation layer of a cap. This model, although simple and convenient to use, does not provide opportunities to incorporate multiple layers with different layer properties. In addition, a conservative modeling approach would examine long-time or steady state behavior. A steady state model of advection, diffusion and reaction processes in a cap layer subject to boundary layer mass transfer and bioturbation is developed. The model retains the important property of simplicity but also provides the ability to evaluate multiple transport processes, the influence of layers with different properties, and allows direct assessment of steady state contamination at environmentally relevant locations, i.e. the biologically active zone.