Suchergebnisse

AbstractReclaimed water irrigation is a beneficial practice that could worsen nitrogen impairment of surrounding waterbodies. Estimating this contribution requires development of a suitable chemical marker. Toward that end, reuse effluents throughout Florida analyzed by liquid chromatography tandem mass spectrometry or high‐resolution atomic mass identified the radiographic contrast medium iohexol as a marker unique to reclaimed water. Because iohexol may be subject to biodegradation during subsurface transport or photolability during surficial flow, this study measured iohexol degradation from solar insolation and its stability relative to nitrate during soil transport for inclusion within a mass balance calculation for a nitrogen impaired surface water in Naples, Florida. In this application, the reuse irrigation fractional volumetric flow contribution was ≤7% of the flow to the impaired waterbody. Subsurface flow was not considered because column experiments with local soil demonstrated preferential denitrification over iohexol biodegradation. Additional studies are needed to further demonstrate the potential merit of this approach in different regions.

AbstractInterest is growing in potable reuse in response to water scarcity and the desire for sustainable supplies. While potable reuse systems must control a variety of physical, chemical, and microbiological contaminants, human enteric viruses are particularly concerning and drive process performance objectives due to their often‐high occurrence in source waters, small size, potential resistance to treatment, and laborious methods to determine infectivity. This paper reviews the alignment of online monitoring practices with the mechanisms and time scales of the various barriers for enteric viruses. While there are numerous studies and reviews of individual barriers, no other review has been identified that covers operational monitoring of the entire potable reuse system. This paper also provides a critical assessment of the efficacy of current practices for operational and verification monitoring of the integrity of barriers to enteric viruses in potable reuse systems. The prevalence of human enteric viruses in wastewater and associated challenges of quantifying them through treatment are discussed within the risk management frameworks currently in use or under development for potable reuse systems. Monitoring approaches are then reviewed throughout the potable reuse water cycle. Current monitoring practices are compared with treatment process mechanisms and time scales, for the treatment barriers of biological wastewater treatment, membrane bioreactors, microfiltration/ultrafiltration, reverse osmosis, ultraviolet irradiation/advanced oxidation, ozonation, granular media/biologically active filtration, and chlorination. Monitoring and pathogen removal mechanisms are also reviewed for both environmental and engineered buffers. Implications are then discussed for future areas of research in potable reuse.

AbstractWater quality, in combination with design and operational data collected from multiple studies, was assessed to benchmark the performance of ozone‐biologically active filtration in reuse applications. A total of 149 contaminants of emerging concern, representative of multiple categories and chemical structures, were prioritized and systematically compared to elucidate apparent differences in removal capabilities as affected by multiple factors such as influent water matrix, ozone‐to‐organic carbon ratio, empty bed contact time, filtration media type, and initial media condition. The results were consistent with earlier findings for the removal of highly amenable compounds but demonstrate inconsistencies and knowledge gaps across multiple facilities for the more persistent compounds. Analysis of this multistudy data‐mining effort also demonstrates a complicated interplay between contaminant removal and numerous design and operational variables. Hence, further systematic investigation is warranted to elucidate the underlying removal mechanisms.