BIOMOC, a Multispecies Solute-Transport Model with Biodegradation

摘要

A two-dimensional, multispecies reactive solute-transport model with sequentialaerobic and anaerobic degradation processes was developed and tested. The model design is general and flexible, permitting simulation of biotransformation reactions for any combination of electron donor and acceptor. In addition, the evolution of redox zones can be simulated, as thermodynamically-favorable electron acceptors are depleted. It allows for multiple particle sets and each particle set is capable of having multiple solute species with similar sorption characterics. Multiple degradation processes and microbial populations can be represented simultaneously. Growth of the biomass is modeled with specified yield and decay values. To illustrate the flexibility of BIOMOC, example applications of the model to two field sites are described. The first example steady-state, one-dimensional, transport and degradation of chlorinated solvents with no biomass growth. The second application is a two-dimensional, transient simulation of the Bemidji, Minnesota crude-oil spill site. In this application, the evolution of redox zones and microbial populations is simulated. The results were used to determine the percentage of mass lost by aerobic versus anaerobic degradation and to understand the evolution of the redox zones in a plume.