Four chloraminated drinking water distribution systems (CDWDSs) required to maintain numeric versus "detectable" residuals were spatially and temporally sampled for water quality and associated trihalomethane (THM) and haloacetic acid (HAA) formation. Monochloramine decreased from entry point (EP) to maximum residence time (MRT) samples while THMs and HAAs initially increased and then stabilized or slightly decreased. Subsequently, EP and MRT samples were used in laboratory-held studies to further evaluate disinfectant residual stability, chloramine speciation, and nitrification occurrence.
View Article and Find Full Text PDFTo evaluate natural organic matter (NOM) processing impacts on preformed monochloramine (PM) reactivity and as a first step in creating concentrated disinfection byproduct (DBP) mixtures from PM, a rational methodology was developed to proportionally scale PM NOM-related demand in unconcentrated source waters to waters with concentrated NOM. Multiple NOM preparations were evaluated, including a liquid concentrate and reconstituted lyophilized solid material. Published kinetic models were evaluated and used to develop a focused reaction scheme (FRS) that was relatively simple to implement and focused on monochloramine loss, including considerations for inorganic chloramine stability (i.
View Article and Find Full Text PDFAutosomal recessive polycystic kidney disease (ARPKD) and other hepatorenal fibrocystic diseases (HRFD) are relatively rare recessive disorders that constitute an important set of childhood nephropathies. Little is known about fundamental pathogenesis, and advances toward clinical trials will require well-characterized patient cohorts and the development of predictive and prognostic biomarkers. Such studies in rare diseases require greater collaboration than the efforts in common diseases where large patient repositories can be built at a single site.
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