The anammox process is an alternative nitrogen removal process where autotrophic anammox bacteria directly convert ammonium to N 2, a harmless gas, using nitrite as the electron acceptor under anaerobic condition. This study focused on one type of high ammonia nitrogen content wastewater and sludge from the anammox process. Wastewater is one of the most complex matrices. This information is needed to be considered when exploring their fate and toxicity, which highly depend on the complex matrices of the aqueous constituents in the environment. These findings on the fate of AgNPs can be used to explain why AgNPs had limited effects on the sludge−retained bacteria which are responsible for the anammox process.Īlthough the environmental behavior of AgNPs has received intensive attention in the last decade, the behavior of nanomaterials in real matrices, especially in wastewater, is generally poorly investigated. 9.3%) was also observed after the addition of sludge and the possible reason may be the production of Ag(NH 3) 2 + by the coexistence of HA from sludge and NH 4 + from SW. 388.8 nm) due to the steric and hindrance effect. −18.4 mV) and smaller aggregates (313.4 vs. Further exposure of SW−diluted AgNPs to sludge (42 mg L −1 humic acid) and induced a more negative ζ−potential (−22.2 vs. The presence of 18.5 mM Cl − in SW formed AgCl 2 −, AgCl (aq) and eventually promoted the dissolution (9.3%) of cit−AgNPs. 21.5 nm), and settlement (80%) of citrate−coated AgNPs (cit−AgNPs) in 220 min.
Results showed that 18.1 mM NH 4 +, 2.11 mM Mg 2+ in SW caused less negative zeta potential (ζ−potential, −18.4 vs. This study aims to quantitatively investigate the fate of AgNPs in synthetic high ammonia nitrogen wastewater (SW) and sludge from an up–flow anaerobic sludge blanket (UASB) anammox reactor using a nanoparticle tracking analysis (NTA), dynamic light scattering (DLS), transmission electron microscope (TEM), and atomic absorption spectroscopy (AAS). AgNPs in wastewater treatment plants aggregate or dissolve, and may affect the microbial community and subsequent pollutant removal efficiency. Silver nanoparticles (AgNPs) are released into the sewage pipes and ultimately wastewater treatment plants during manufacturing, use, and end–life disposal.
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