The public domain model, BIOCHLOR, provided by the Center for Subsurface Modeling Support (CSMoS) of USEPA is an easy-to-use screening model that simulates aquifer remediation by natural attenuation of (RNA) of dissolved multi-species solvents at chlorinated solvent release site. In our on-going project, we have proven that the BIOCHLOR makes predictions markedly distinct from the well-known reactive transport model, HYDROGEOCHEM and a novel analytical model is presented for simulating multi-species dissolved chlorinated solvent transport problem. The newly derived model can predicts the same results as the HYDROGEOCHEM.