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Issue link: http://wateronline.epubxp.com/i/816402
By Justin Mattingly P otable reuse of advanced treated reclaimed water is achieved through multibarrier treatment trains, using a combination of technologies such as microfiltration, reverse osmosis, advanced oxidation, ozonation, and/ or granular activated carbon. To ensure efficacy of treatment, water quality may be evaluated in real time to verify that these barriers are operating as designed and to reassure communities that there are no adverse public health effects from using reclaimed water for potable purposes. A research team led by Dr. Ian Pepper and Dr. Shane Snyder from the University of Arizona recently completed a study funded by the Water Environment & Reuse Foundation ( WE&RF;), U.S. Bureau of Reclamation, The Pentair Foundation, and Singapore PUB to evaluate the ability of online sensors to ensure that advanced treatment of reclaimed water before potable reuse eliminates chemical and microbial contaminants. Specifically, the researchers sought to determine if real-time sensors could be used for process control of advanced treatment systems to ensure the safety of potable water for the community. Monitoring for Reliability and Process Control of Potable Reuse Applications (Reuse-11-01) is the research title. The team conducted the research in four phases: • Comprehensive literature review • Laboratory evaluations • Pilot-scale utility evaluations • Full-scale utility evaluations Real-time detection of trace organic compounds was evaluated through sensors for surrogate parameters such as UV254 or fluorescence. For microbial contaminants, techniques such as multi-angle light scattering or measurements of adenosine triphosphate (ATP) were used. Advanced treatment technologies that were evaluated included advanced oxidation, reverse osmosis, and activated carbon. From Lab To Pilot-Scale Laboratory evaluations at the University of Arizona Sensors Lab tested eight different advanced treatment methods to determine their efficacy in removing chemical and microbial contaminants. The pilot-scale evaluations involved going beyond bench-scale testing and into monitoring and sensor validation at pilot-scale facilities. The facilities sampled at various critical control points in the system using existing online monitoring systems to monitor the surrogates and indicators proved to be the most useful based on the results of the laboratory evaluation. The last phase conducted full-scale evaluations at facilities that currently implement potable reuse to determine the effectiveness of online monitoring systems. The pilot-scale evaluations occurred at the Beenyup Wastewater Treatment Plant in Australia, Sacramento Regional Wastewater Treatment Plant, and the Tucson Water Sweetwater Recharge Infiltration Systems. Each facility tested advanced treatment options and identified solutions to improve their process control. Overall, the pilot-scale studies demonstrated that select online sensors were able to provide effective process control. Specifically, ozonation more effectively reduced total microbial load and bacteriophage MS2 levels, indicating that total microbial load may be an effective surrogate for pathogen reduction in treatment trains. Real-time detection methods specific to microorganisms were also shown to have potential 26 wateronline.com n Water Innovations Real-Time Monitoring: An Opportunity To Engage In Potable Reuse And Detect Failures Quickly With public safety of primary concern, real-time sensors may be the catalyst for assurance and expansion of potable reuse treatment schemes. Real-time monitoring offers the opportunity to engage in potable reuse with the ability to detect failures quickly and greatly reduce the response time needed to rectify upsets in a treatment system.