Biopiles are a common treatment worldwide for the ex-situ remediation of contaminated soil. Much research has been carried out on understanding and modelling microbial degradation, but hitherto no study has attempted to model the effect on a biopile of its ambient surroundings. This paper presents a Computational Fluid Dynamics (CFD) approach to modelling a biopile under the influence of wind pressure, with and without forced aeration. In addition to the flow, temperature and bioreactions are simulated. Preliminary results indicate that the modelled flow within the pile is in qualitative accordance with a previous analytic solution, and that wind pressure and aeration have a significant effect on the evolution of temperature within the pile. Results also indicate that a very high proportion of contaminant loss from the pile is due to venting to the atmosphere, rather than to microbial degradation.