(1) transport of reactive contaminants in heterogeneous porous media
(2) rate-limited inter-phase mass transfer (e.g. diffusion, sorption/desorption, NAPL dissolution); (3) behavior of complex contaminant systems (multi-solute, multi-solvent, multi-phase)
(4) coupled processes such as inter-phase mass transfer and biodegradation
(5) vapor-phase transport