The separation of metals from aqueous streams by continuous polymer enhanced ultrafiltration (PEUF) was simulated in order to understand, evaluate and optimize the process feasibility. The model allows one to examine the influence of physico-chemical and operation variables on the metal reduction and productivity of the treated water stream. For a given metal-polymer system, the computations revealed that the most influential operation variables are the acid and base reagents expended on the process, the amount of polymer used and the recycling stream flow, which are represented by the dimensionless parameters af, pp and to, respectively. Two of them can be free chosen while the third one is determined by a fixed treated water production and metal reduction. The selection of af and pp values should be a compromise between the costs of the reagents to regenerate the polymer and the energy spent to achieve a permeate flow. If process efficiency requirements are more exigent, higher values of af or pp are required. (c) 2005 Elsevier B.V. All rights reserved.