Three Brown and Caldwell water leaders explore how communities are tailor-fitting reuse strategies and technologies in the March 2017 American Water Works Association Journal article: “Potable Reuse: Where We’ve Been and Where We’re Headed,” by Sunny Wang, water technology leader, Wendy Broley, water reuse practice leader, and Erin Mackey, technical specialist for drinking water and reuse.
“Potable Reuse: Where We’ve Been and Where We’re Headed,” was published in its entirety on BC Water News.
The article looks at several factors including new regulations, climate change, severe drought conditions, public perception, and technology advancements that has put the spotlight on potable reuse best practices. These best practices build on proven and well established advanced water treatment technologies including microfiltration (MF), reverse osmosis (RO), and ultraviolet light advanced oxidation process with hydrogen peroxide (UV AOP).
Both IPR (indirect potable reuse) and DPR (direct potable reuse) are addressed in the article.
“Each utility has taken a different optimization approach to enhance performance, water quality, and reliability to meet their own specific needs,” Wang said.
Some examples in the article:
- Orange County Water District Enhanced Overall Groundwater Quality: During initial expansion of Orange County Water District’s Groundwater Replenishment System to produce 100 mgd of purified water, an alternative post-treatment stabilization strategy was developed to minimize the mobilization of metals, particularly arsenic, in the groundwater aquifer. The alternative water quality target included lowering final purified water pH and increasing calcium content that is more representative of groundwater quality from natural recharge.
- Water Replenishment District of Southern California Produced More with Less: Because of space limitations at the Leo Van der Lans Water Treatment Facility during an expansion, this utility implemented a new microfiltration backwash recovery system and reconfigured the reverse osmosis setup to increase recovery and overall production within the existing plant’s footprint.
- City of San Diego Pioneering Surface Water Augmentation: Due to limited groundwater aquifer capacity and to reduce reliance on imported water supplies, the City of San Diego incorporated additional treatment barriers, ozone and biologically activated carbon filtration in front of the full advanced treatment train (MF + RO + UV AOP) in order to send purified water to the Miramar Reservoir.
- City of Oxnard Implementing Aquifer Storage of Purified Water: Purified water is injected into a confined groundwater aquifer for the regulated retention time before it is pumped out of the same well and treated for drinking water use.