Multiperiod design of regional wastewater systems: Generating and evaluating alternative plans

A simplified method is proposed for analyzing multiperiod design of regional wastewater systems and other systems possessing a similar network flow structure. The primary objective of the method is generation of multiperiod locations and facility expansion timings. The method is based on several simplifying assumptions. The solution procedure involves a branch and bound algorithm specifically developed for integrating a set of solutions obtained using the initial design flow with a set of solutions obtained using the terminal design flow. A method for comparing the generated multiperiod alternatives is also proposed. The usefulness of the method is demonstrated, using as an example a hypothetical regional waste water system. A Fortran program was written to implement the method. The program is not in a form that would permit its transfer, but interested readers may contact the first author.