Decision support toolkit for integrated analysis and design of reclaimed water infrastructure

Abstract

Planning of water reuse systems is a complex endeavor. We have developed a software toolkit, IRIPT (Integrated Urban Reclaimed Water Infrastructure Planning Toolkit) that facilitates planning and design of reclaimed water infrastructure for both centralized and hybrid configurations that incorporate satellite treatment plants (STPs). The toolkit includes a Pipeline Designer (PRODOT) that optimizes routing and sizing of pipelines for wastewater capture and reclaimed water distribution, a Selector (SelWTP) that assembles and optimizes wastewater treatment trains, and a Calculator (CalcBenefit) that estimates fees, revenues, and subsidies of alternative designs. For hybrid configurations, a Locator (LocSTP) optimizes siting of STPs and associated wastewater diversions by identifying manhole locations where the flowrates are sufficient to ensure that wastewater extracted and treated at an adjacent STP can generate the revenue needed to pay for treatment and delivery to customers. Practical local constraints are also applied to screen and identify STP locations. Once suitable sites are selected, System Integrator (ToolIntegrator) identifies a set of centralized and hybrid configurations that: (1) maximize reclaimed water supply, (2) maximize reclaimed water supply while also ensuring a financial benefit for the system, and (3) maximize the net financial benefit for the system. The resulting configurations are then evaluated by an Analyst (SANNA) that uses monetary and non-monetary criteria, with weights assigned to appropriate metrics by a decision-maker, to identify a preferred configuration. To illustrate the structure, assumptions, and use of IRIPT, we apply it to a case study for the city of Golden, CO. The criteria weightings provided by a local decision-maker lead to a preference for a centralized configuration in this case. The Golden case study demonstrates that IRIPT can efficiently analyze centralized and hybrid water reuse configurations and rank them according to decision-makers' preferences.

Keywords: Decision support tool; Integrated planning tool; Multi-criteria decision analysis; Reclaimed water; System optimization; Water reuse.