Part 1 of the series proposes a multiscale state-space superstructure for interplant water-allocation and heat-exchange networks' (IWAHENs) design with direct and indirect integration schemes in fixed flow rate (FF) processes (Zhou, R. J.; Li. L. J.; Dong, H. G.; Grossmann, I. E. Synthesis of Interplant Water-Allocation and Heat-Exchange Networks. Part 1: Fixed Flowrate Processes. Ind. Eng. Chem. Res. 2012, 51, 4299). Based on the same superstructure, part 2 of this series extends the IWAHEN integration methods to fixed contaminant-load (FC) processes as well as integration of FF and FC processes. The integrations are performed by solving the corresponding mixed-integer nonlinear programming (MINLP) models based on the multiscale state-space superstructure. Several relevant examples, including both direct and indirect integrations for IWAHENs, are presented to illustrate various aspects of the proposed approach.