In most environments, ammonia (NH₃) is oxidized to nitrate (NO₃⁻) via the intermediate nitrite (NO₂⁻). This is a microbe-driven process involving phylogenetically distinct types of microorganisms, namely, ammonia-oxidizing bacteria (AOB) and Thaumarchaea (AOA), and nitrite-oxidizing bacteria (NOB). Nitrosomonas europaea and Nitrobacter winogradskyi are the best studied AOB and NOB, respectively,...
Due to the effective antimicrobial properties of silver nanoparticles they represent a significant proportion of all consumer-‐related nanomaterials. The introduction of silver nanoparticles from these products into domestic and industrial wastewater streams poses potential complications for biological treatment systems. A critical component of biological treatment that is extremely sensitive to...
Nitrification is a critical step in the global nitrogen cycle involving the biological oxidation of ammonia (NH₃) to nitrite (NO₂⁻ ) and then to nitrate (NO₃⁻). The first step in nitrification is carried out by NH₃-oxidizing bacteria (AOB) and archaea (AOA), and the second by NO₂⁻-oxidizing bacteria (NOB). In addition...
A year-long, bench-scale treatability study was performed to assess whether an activated sludge sequencing batch reactor could be used to treat an influent stream of 50/50 (v/v) municipal wastewater and landfill leachate to discharge standards established by the Oregon Department of Environmental Quality. One primary obstacle that was exposed during...
Nitrification is the process within the global Nitrogen Cycle where ammonia (NH3) is oxidized to nitrate (NO₃⁻) and can be carried out by two distinct groups of bacteria. The ammonia-oxidizing bacteria (AOB) first oxidize NH₃ to nitrite (NO₂⁻), and second, the nitrite-oxidizing bacteria (NOB) oxidize NO₂⁻ to NO₃⁻. In aerobic...
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Luis A. Sayavedra-Soto
Nitrification is the process within the global Nitrogen Cycle where
Silver nanoparticles are increasingly being incorporated into consumer products due to their broad-spectrum antimicrobial properties. The resulting influx of silver nanoparticles into wastewater may pose a threat to bacteria involved in biological wastewater treatment. Ammonia-oxidizing bacteria, which convert ammonia to nitrite in the first step of nitrification, are highly sensitive...
Nitrification and denitrification are major biological processes transforming nitrogen (N) in soils to plant available N, highly leachable nitrate (NO₃⁻) and gaseous N oxides. Although many studies in the past have studied N cycling communities, the effect of increased N inputs on ammonia-oxidizer and denitrifier population dynamics is still under...
Prior to 2005, ammonia oxidation, the first step of nitrification, was thought mediated mainly by ammonia-oxidizing bacteria (AOB). However, the discovery of Thaumarchaeota carrying the genes coding for the ammonia monooxygenase (AMO) enzyme led to the discovery that ammonia-oxidizing archaea (AOA) also contribute to nitrification. Despite the uptick in studies...