Optimization model for cost estimation of decentralized wastewater treatment units

Abstract

In this study, an optimization model, which is a combination of Genetic algorithm (GA) and geographical information system (GIS) was used to find minimum construction, operation, and flow reuse cost ( Fmin) . This Fmin model will be used for the estimation of the constructional and operational costs of decentralized wastewater treatment units [DTUs] and can be used for the estimation of reusing treated municipal wastewater flow for irrigation purposes in Sulaimani city, Iraq as well. In the optimization processes, an objective function technique was used based on data from 31 small-sized DTU and the costs of reusing their effluents in 827 deferent sizes green areas [GRs] across the city. A transportation matrix model of size [31x827] was built to find the Fmin for conveying the required flow from the DTUs to the GRs destinations. Also, optimum required pipe lengths and routes for the treated flow conveying were found using GIS Network Analysis – Origin-Destination (OD) Matrix Tools. The results showed that the proposed model could successfully obtain an optimal solution. The algorithm is flexible enough to consider a variety of scenarios and compare the best options.