Centralized versus decentralized wastewater reclamation in the Houghton area of Tucson, Arizona.

AbstractReclaimed wastewater is increasingly important to satisfaction of water-sustainability objectives in water-short municipalities throughout the United States and particularly in the Southwest. Water reclamation and reuse present new challenges for urban planners, who now tend to consider renewable freshwater and reclaimed wastewater as unique parts of a single water resources portfolio. Efficiency objectives in geographically dispersed communities lead planners to explore the relative merits of centralized versus decentralized wastewater-treatment capacity when new construction is required. However, the complexity of the planning landscape—in which existing water distribution and sewerage capacities; geographic factors; and uncertainty in growth projections, energy cost, and even the sustainability of existing freshwater supplies contribute to plan selection—suggests that decision support methods can usefully supplement engineering judgment to find a near-optimal level of decentralization in facili...