SELENIUM REMOVAL IN NUTRIENT-AMENDED PILOT-SCALE CONSTRUCTED WETLAND TREATMENT SYSTEMS

ABSTRACT In a year-long study, pilot-scale constructed wetland treatment systems (CWTSs) targeted removal of selenium (Se) from a simulated impaired water through dissimilatory Se reduction. Effects of temperature and precipitation on the treatment of Se in the CWTSs were investigated. The experimental design consisted of CWTSs amended with a fermented yeast product (AquaSmartTM, Diamond V¨, Cedar Rapids, IA), which served as a nutrient source for Se-reducing bacteria, at mass loadings of 1.75, 3.5, 5.25, 7, and 8.75 mg/min. The 5 µg/L treatment goal for CWTS outflow concentration was measured in 69 of 378 samples taken from all CWTSs. Of the 69 samples that met the treatment goal, 7.2, 7.2, 10.1, 10.1, 31.9 and 33.3% of the samples occurred in the control, 1.75, 3.5, 5.25, 7, and 8.75 mg AquaSmart/min treatment groups, respectively. CWTSs amended with AquaSmartTM mass loading rates of 8.75 and 7 mg/min consistently reduced aqueous concentrations of Se from 50 μg/L to less than 5 μg/L, meeting the USEPA chronic water criterion for Se (USEPA, 2002; 2004). Se removal efficiency correlated positively with nutrient amendment loading. Nutrient amendment addition provided nutrients and energy to Se-reducing bacteria allowing for Se reduction, and therefore Se removal, to continue through the winter months. The influence of seasonal temperature change on Se removal efficiency in CWTSs decreased with increased nutrient mass loading. Seasonal temperature decrease greatly impacted Se removal in the control, 1.75, 3.5, and 5.25 mg/min treatment groups. CWTSs amended with AquaSmartTM at mass loadings of 8.75 and 7 mg/min achieved greater Se removal efficiency than the control CWTSs as temperature decreased. R2 values determined from comparison of mean removal efficiency and temperature ranged from 0.18 for the 8.75, and 7 mg/min loading to 0.67 for a control group with no amendment added. Dissolved oxygen (DO) concentration of 2 mg/L or less and negative oxidation-reduction potential influenced Se removal. Measured precipitation did not correlate strongly to Se removal. Results from this study indicate that Se removal to less than 5 µg/L can be achieved in CWTSs and is aided by the addition of AquaSmartTM. Nutrient-amended CWTSs may provide industry with a viable technology to treat waters containing elevated levels of Se

Empirical evidence for the expressive-collaborative model of morality and its implications for healthcare ethics consultation

University of Minnesota M.A. thesis. November 2014. Major: Bioethics. Advisor: Joan Liaschenko, PhD, RN, FAAN. 1 computer file (PDF); iv, 77 pages.With the hopes of guiding the future development of HCEC, this paper attempts to better understand the nature of morality by integrating moral psychologist Jonathan Haidt's theory of human functioning in moral contexts with Margaret Urban Walker's work in moral philosophy. First, I present Margaret Urban Walker's two contrasting philosophical views of morality: the theoretical-juridical model (TJM) of morality and the expressive-collaborative model (ECM) of morality. Second, I present evidence suggesting that traditional models of how people make moral judgments overestimate the causal role of reasoning and underestimate the causal role of emotions. Third, I present a model of moral judgment that I believe meets these two criteria: Jonathan Haidt's social intuitionist model (SIM) of moral judgment. Finally, I discuss how the SIM can be applied to HCEC to guide practice

Introducing: Oxford

Binnenkort brengt de B.I.L. een bezoek aan Oxford. Detlev van Heest brengt u alvast in de stemming met de navolgende reportage