Leather tanning processing involves treatment of skin in chrome baths where the percentage exhaustion of chromium salts is usually in the range of 60-70%. Excess chromium salts are discharged to the sewer system or an effluents treatment facility. Thus, extensive efforts have been exerted on both R&D and application levels to recover chromium for economic and environmental concerns. Several methods have been developed for chromium recovery or reuse including precipitation, adsorption, redox-adsorption, ion-exchange and membrane systems. Recent research indicated that chromium salts recovered by membranes manifested improved characteristics for tanned and retanned skins. This paper is dedicated to the simulation and optimization of dual-membrane systems involving inorganic ultrafiltration and nanofiltration for the recovery of chromium from effluents of exhausted baths. In the first section, parameters governing the separation of protein/fat mix by ultrafiltration are obtained by analysis of published results on separation of proteins by ultrafiltration. The parameters for the concentration of chromium by nanofiltration are also deduced. A simulation model based on the resistance model and involving material balance and energy requirements for the ultrafiltration-nanofiltration scheme has been developed. A cost-objective function involving annual costs and revenues has been formulated. Optimum design parameters have been defined using a Box COMPLEX constrained optimization routine. Results indicated that under the stated optimum conditions the system is cost effective.