Representing wastewater recycling in an integrated urban water modelling tool

Treated wastewater is increasingly being considered as an alternative supply source in urban areas. Assessing its feasibility requires simulating its use using a suitable model. The feedback inherent in any wastewater recycling scenario creates challenges when determining how water from different types of sources like surface water, groundwater and treated wastewater should be allocated to meet demands. This is especially important when an optimisation algorithm determines the water allocation strategy. Releases from surface water sources can be reduced if supply from treated wastewater can be modelled. This allows for more efficient management of the water supply, leading to increased storage levels and fewer demand deficits. HydroPlanner is an integrated modelling tool developed in part to predict the effects of wastewater treatment and reuse on the supply network. It combines rainfall runoff models, storage models, demand models and wastewater recycling models together in the simulation of urban water systems. This paper demonstrates that HydroPlanner can model regulated river network systems equivalently to established platforms such as REALM. Additionally it is shown that HydroPlanner can specifically model wastewater treatment and the supply of treated water back to demands, though a further case study is planned to prove its validity for this purpose.