Publications by authors named "Donald R Ryan"

Improved treatment of per- and polyfluoroalkyl substances (PFAS) in water is critically important in light of the proposed United States Environmental Protection Agency (USEPA) drinking water regulations at ng L levels. The addition of peroxymonosulfate (PMS) during electrooxidation (EO) can remove and destroy PFAS, but ng L levels have not been tested, and PMS itself can be toxic. The objective of this research was to test peroxydisulfate (PDS, an alternative to PMS) activation by boron-doped diamond (BDD) electrodes for perfluorooctanoic acid (PFOA) degradation.

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Conventional wastewater treatment processes cannot effectively remove dissolved organic nitrogen (DON) and soluble non-reactive phosphorus (sNRP), which can pose regulatory compliance challenges for total nitrogen and total phosphorus discharges. Moreover, DON and sNRP are not easily recoverable for beneficial reuse as part of the waste to resource paradigm. Conversion of DON and sNRP to more readily removable dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (sRP), respectively, will help meet stringent nutrient limits and facilitate nutrient recovery.

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In-situ water treatment can be accomplished using electrochemical treatments such as electrocoagulation (EC), which generates coagulants, and electrooxidation (EO), which generates oxidants (e.g., free chlorine and reactive oxygen species) via electrolysis using boron-doped diamond electrodes.

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Electrochemical water treatment is a promising alternative for small-scale and remote water systems that lack operational capacity or convenient access to reagents for chemical coagulation and disinfection. In this study, the mitigation of viruses was investigated using electrocoagulation as a pretreatment prior to electrooxidation treatment using boron-doped diamond electrodes. This research is the first to investigate a sequential electrocoagulation-electrooxidation treatment system for virus removal.

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Purpose: To compare the relative use of bilateral versus unilateral extremity radiographic examinations when patients are referred to radiologists for imaging (radiologist referred) versus when studies are performed in the referring physician's office (self-referred).

Materials And Methods: We reviewed 1 year of claims data for extremity radiographic examinations performed by a referring physician or referred to a radiology facility and claims data for related patient office visits. Data were analyzed for orthopedics, podiatry, and rheumatology, and data were divided by the practice pattern of the referring physician into pure self-referring, pure radiologist-referring, and mixed-referring categories.

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