Browsing by Subject "Water Purification"

Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Elucidating the impact of microbial community biodiversity on pharmaceutical biotransformation during wastewater treatment.
    (Microbial biotechnology, 2018-11) Stadler, Lauren B; Delgado Vela, Jeseth; Jain, Sunit; Dick, Gregory J; Love, Nancy G
    In addition to removing organics and other nutrients, the microorganisms in wastewater treatment plants (WWTPs) biotransform many pharmaceuticals present in wastewater. The objective of this study was to examine the relationship between pharmaceutical biotransformation and biodiversity in WWTP bioreactor microbial communities and identify taxa and functional genes that were strongly associated with biotransformation. Dilution-to-extinction of an activated sludge microbial community was performed to establish cultures with a gradient of microbial biodiversity. Batch experiments were performed using the dilution cultures to determine biotransformation extents of several environmentally relevant pharmaceuticals. With this approach, because the communities were all established from the same original community, and using sequencing of the 16S rRNA and metatranscriptome, we identified candidate taxa and genes whose activity and transcript abundances associated with the extent of individual pharmaceutical biotransformation and were lost across the biodiversity gradient. Metabolic genes such as dehydrogenases, amidases and monooxygenases were significantly associated with pharmaceutical biotransformation, and five genera were identified whose activity significantly associated with pharmaceutical biotransformation. Understanding how biotransformation relates to biodiversity will inform the design of biological WWTPs for enhanced removal of chemicals that negatively impact environmental health.
  • Thumbnail Image
    ItemOpen Access
    Functional elastic hydrogel as recyclable membrane for the adsorption and degradation of methylene blue.
    (PloS one, 2014-01) Bao, Song; Wu, Dongbei; Wang, Qigang; Su, Teng
    Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young's modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g(-1). The hydrogel also exhibited higher separation selectivity to Pb(2+) than Cu(2+). The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables.
  • Thumbnail Image
    ItemOpen Access
    Supercritical water oxidation of a model fecal sludge without the use of a co-fuel.
    (Chemosphere, 2015-12) Miller, A; Espanani, R; Junker, A; Hendry, D; Wilkinson, N; Bollinger, D; Abelleira-Pereira, JM; Deshusses, MA; Inniss, E; Jacoby, W
    A continuous supercritical water oxidation reactor was designed and constructed to investigate the conversion of a feces simulant without the use of a co-fuel. The maximum reactor temperature and waste conversion was determined as a function of stoichiometric excess of oxygen in order to determine factor levels for subsequent investigation. 48% oxygen excess showed the highest temperature with full conversion. Factorial analysis was then used to determine the effects of feed concentration, oxygen excess, inlet temperature, and operating pressure on the increase in the temperature of the reacting fluid as well as a newly defined non-dimensional number, NJa representing heat transfer efficiency. Operating pressure and stoichiometric excess oxygen were found to have the most significant impacts on NJa. Feed concentration had a significant impact on fluid temperature increase showing an average difference of 46.4°C between the factorial levels.