Abstract: This paper describes a mathematical model and an algorithm which can be used for simulation of in-terlinked column systems consisting of liquid-liquid extraction and distillation.This algorithm is basedupon Newton-Raphson iteration technique using suitable damping factors and solutions of simplified modelas initial values of exact calculations.With the exception of principle specification it is possible to interchangethe iteration variables and/or noniteration variables with design variables to meet requirements of design.A process of recovery of phenol from waste water containing pheonol is illustrated to varify the model andalgorithm.The results are satisfied.