Water reuse versus water conveyance for supply augmentation: Cost and carbon footprint.

Water‐stressed communities are beginning to consider alternative sources of water supply augmentation. We provide a comparison of water conveyance and potable water reuse over a range of water demands. On a unit basis (US$/1,000 gal) and under current practice, water reuse is generally less costly at low flow rates (<10 mgd) as compared with water conveyances of 20 miles or more. This is true especially for advanced water treatment schemes that are based on biologically activated carbon (BAC). At greater distances (>100 miles), treatment schemes that are based on reverse osmosis (RO) also become cost competitive. Similarly, both BAC‐based and RO‐based reuse schemes have a lower or comparable carbon footprint on a unit basis (g CO2‐equiv/1,000 gal) for a flow rate of 20 mgd. In spite of public reluctance, managers would do well to consider reuse in their portfolio of water supply options. [ABSTRACT FROM AUTHOR]