Regionalization of Wastewater Collection and Treatment Location,Scale and Construction Sequence of System Components.

摘要

A mixed integer programming model was developed for the analysis of alternatives concerning extensive regional wastewater planning. Application to a typical problem in Pennsylvania involved about 1000variables and 1000constraints. The model was found to be difficult and expensive to solve,requiring extensive expertise in mathematical programming. Research reported was intended to: (1) make the objective function of the previous model conform more closely to the EPA's planning guidelines; (2) reduce problem set-up time; (3) improve the solution strategy;and (4) demonstrate applicability to real problems. Work was done to take account of such things as treatment process upgrading,useful economic life of existing facilities,salvage values,inflation, O and M,and replacement costs. In order to shorten problem set up time, a matrix generation program was written that reduces the input data deck for a typical problem from 3000to 300cards. The solution strategy employed relies on linear instead of mixed integer programming. Using engineering judgment or the results of preliminary screening runs with the computer,the user must select alternative times and places for construction. Numerous alternatives can be investigated in a few man-days,each solution requiring between 1and 2minutes,CPU time. The model was applied to three ongoing '201'studies with the cooperation of two different firms of consulting engineers to demonstrate its applicability.