Potable Reuse Treatment Trains Throughout the World

Potable reuse is becoming an increasingly common strategy for bolstering water resource portfolios in water-scarce regions. Each application poses unique challenges, whether related to treatment goals, regulatory requirements, or political and public acceptance, and these issues have a significant impact on the final treatment train selection. This review describes the various potable reuse frameworks and illustrates the importance of environmental buffers as a treatment barrier and as a distinction between ‘indirect’ and ‘direct’ potable reuse applications. This review also highlights more than 20 potable reuse treatment trains currently in operation or under construction throughout the world. The unit processes in each train are identified and a brief summary of their advantages and limitations in relation to alternative processes is included

Applicability of Ozone and Biological Activated Carbon for Potable Reuse

<div><p>The Upper San Gabriel Valley Municipal Water District in California is considering groundwater replenishment as a potential strategy to augment its potable water supply. This case study demonstrates the broad applicability of ozone and biological activated carbon (BAC) for such potable reuse systems based on recently developed criteria and models for bulk organics, trace organic contaminants, disinfection byproducts, and cost. Using an advanced treatment train composed of ozone (ozone to total organic carbon ratio of 1.0) and BAC (empty bed contact time of 20 min), a 10 million gallon per day potable reuse facility can achieve savings of $25–$51 million in capital costs, $2–$4 million per year in operations and maintenance costs, and 4–8 GWh per year in energy consumption in comparison to alternative treatment trains with reverse osmosis. This ozone-based treatment train is also capable of achieving public health criteria recently developed by the California Department of Public Health and the National Water Research Institute for potable reuse applications.</p></div