Browsing by Subject "Sewage"

Now showing 1 - 3 of 3
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    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.
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    ItemOpen Access
    Sensor-mediated granular sludge reactor for nitrogen removal and reduced aeration demand using a dilute wastewater.
    (Water environment research : a research publication of the Water Environment Federation, 2020-07) Bekele, Zerihun A; Delgado Vela, Jeseth; Bott, Charles B; Love, Nancy G
    A sensor-mediated strategy was applied to a laboratory-scale granular sludge reactor (GSR) to demonstrate that energy-efficient inorganic nitrogen removal is possible with a dilute mainstream wastewater. The GSR was fed a dilute wastewater designed to simulate an A-stage mainstream anaerobic treatment process. DO, pH, and ammonia/nitrate sensors measured water quality as part of a real-time control strategy that resulted in low-energy nitrogen removal. At a low COD (0.2 kg m-3  day-1 ) and ammonia (0.1 kg-N m-3  day-1 ) load, the average degree of ammonia oxidation was 86.2 ± 3.2% and total inorganic nitrogen removal was 56.7 ± 2.9% over the entire reactor operation. Aeration was controlled using a DO setpoint, with and without residual ammonia control. Under both strategies, maintaining a low bulk oxygen level (0.5 mg/L) and alternating aerobic/anoxic cycles resulted in a higher level of nitrite accumulation and supported shortcut inorganic nitrogen removal by suppressing nitrite oxidizing bacteria. Furthermore, coupling a DO setpoint aeration strategy with residual ammonia control resulted in more stable nitritation and improved aeration efficiency. The results show that sensor-mediated controls, especially coupled with a DO setpoint and residual ammonia controls, are beneficial for maintaining stable aerobic granular sludge. PRACTITIONER POINTS: Tight sensor-mediated aeration control is need for better PN/A. Low DO intermittent aeration with minimum ammonium residual results in a stable N removal. Low DO aeration results in a stable NOB suppression. Using sensor-mediated aeration control in a granular sludge reactor reduces aeration cost.
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    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.