Although ultraviolet (UV) and persulfate (PS) have been widely used in water disinfection process, their incompleteness of disinfection, such as inducing the production of viable but non-culturable cells (VBNC), has attracted extensive attention. In this study, the disinfection effect of combined UV and PS was evaluated from the perspective of inducing Pseudomonas aeruginosa into VBNC, and the roles of SO 4•− and HO • radicals in UV/PS disinfection were also analyzed. UV/PS more effectively inactivated cells and reduced the number of culturable cells, but induced more VBNC cells. On the other hand, the test of bacterial dark activation suggested that UV/PS disinfection effectively prolongs the recovery time of VBNC cells. The mechanisms of UV/PS disinfection were the increase of membrane permeability and oxidative stress, where SO 4•− radicals played more role than HO • radicals. Furthermore, UV/PS disinfection more signi cantly perturbed the metabolism of Pseudomonas aeruginosa (p < 0.05), mainly involving glyoxylate and dicarboxylic acid metabolism, aminoacyl-tRNA biosynthesis, Alanine, aspartate and glutamate metabolism, citric acid cycle (TCA cycle). This study, from the production and recovery of VBNC, provides a new idea for the evaluation of UV, persulfate and their combined disinfection effect, and provides guidance for improving disinfection process.
BPS, as a widespread environmental hormone-like micro-pollutants, is di cult to be degraded in the environment. In this study, the removal of BPS with multi-enzymes extracted from waste sludge and reed sediment were studied at 25℃, 37℃ and 55℃. Results show that BPS could be removed e ciently, which could involve enzymolysis and bio-occulation. The mechanism and pathways of the enzymolysis were identi ed with LC-MS/MS. Polymerization of BPS with enzymolysis further improved the removal by bio-occulation due to the production of BPS oligomers. Furthermore, the interaction mechanism between BPS and multi-enzymes was explored through a series of spectroscopic experiments. Results show that more loose skeletal structure of the multi-enzymes and more hydrophobic microenvironment of the amino acid residues are responsible for the removal of BPS. This research not only provided a method for refractory micropollutants removal but also a way for the utilization of waste sludge and reed sediment.
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