As a class of alternative flame retardants, "novel" brominated flame retardants (NBFRs) have been widely used in clothing, textiles, electronics, building materials, and plastics and are frequently found in environmental samples. Although the use and discharge of NBFRs are increasing all over the world, little information is available about their fates and removal in wastewater treatment plants (WWTPs). This study investigated the occurrence and behavior of 2,4,6-tribromophenyl allyl ether (ATE), 2,3-dibromopropyl tribromophenyl ether (DPTE), tetrabromo-o-chlorotoluene (TBCT), pentabromobenzyl acrylate (PBBA), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (TBPH), and decabromodiphenyl ethane (DBDPE) in a municipal WWTP in Beijing, China. Four of the NBFRs (ATE, BTBPE, TBPH, and DBDPE) were detected in all wastewater and biosolid samples. The dominant compound in both wastewater and biosolid samples was DBDPE, with concentrations in the ranges of 6.4-18 ng/L and 83-288 ng/g dry weight (dw), respectively. A mass flow analysis indicated that the overall removal efficiencies were 31±18% for ATE, 97±1.5% for DPTE, 79±11% for BTBPE, 87±5.3% for TBPH, and 93±3.3% for DBDPE, but the removal efficiency in aqueous phase only ranged from -43 (ATE) to 57% (DBDPE). The low and negative removal efficiencies of ATE were possibly due to the transformation of DPTE during the anaerobic treatment processes. Under the aerobic conditions, BTBPE, TBPH and DBDPE underwent a very slow biodegradation. A total of 68-91% of the initial mass loadings of ATE, BTBPE, TBPH and DBDPE were found in the biosolid samples, suggesting that the four NBFRs were removed mainly via sorption in the WWTP.The biosolid was a huge reservoir of target NBFRs, and effective removal of NBFRs during treatment in the WWTP is critical.This study investigated the removal of three selected micropollutants (i.e., bisphenol A, diclofenac and caffeine) in drinking water using the UV-LED/chlorine advanced oxidation process (AOP) followed by activated carbon adsorption. The degradation of bisphenol A, diclofenac and caffeine was predominantly contributed by chlorination (>60%), direct UV photolysis (>80%) and radical oxidation (>90%), respectively, during the treatment by the UV-LED/chlorine AOP at three tested UV wavelengths (i.e., 265, 285 and 300 nm). The most effective UV wavelengths for the degradation of bisphenol A, diclofenac and caffeine were 265, 285 and 300 nm, respectively. The degradation of all the three micropollutants was enhanced with increasing pH from 6 to 8, though the reasons for the pH dependence were different. The residues of the micropollutants and their degradation (by)products were removed by post-adsorption using granular activated carbon (GAC). Interestingly and more importantly, the adsorption rates of the degradation (by)products were 2-3 times higher than the adsorption rates of the corresponding micropollutants, indicating the formation of more adsorbable (by)products after the AOP pre-treatment. The UV-LED/chlorine AOP followed by GAC adsorption provides a multi-barrier treatment system for enhancing micropollutant removal in potable water. The findings also suggest the merit of the sequential use of UV-LEDs followed by GAC in treating chlorine-containing potable water in small-scale water treatment systems (e.g., point-of-use or point-of-entry water purifiers).The formation of N-nitroso-ciprofloxacin (CIP) was investigated both in wastewater treatment plants including nitrification/denitrification stages and in sludge slurry experiments under denitrifying conditions. https://www.selleckchem.com/products/pnd-1186-vs-4718.html The analysis of biological wastewater treatment plant effluents by Kendrick mass defect analysis and liquid chromatography - high resolution - mass spectrometry (LCHRMS) revealed the occurrence of N-nitroso-CIP and N-nitroso-hydrochlorothiazide at concentration levels of 34 ± 3 ng/L and 71 ± 6 ng/L, respectively. In laboratory experiments and dark conditions, produced N-nitroso-CIP concentrations reached a plateau during the course of biodegradation experiments. A mass balance was achieved after identification and quantification of several transformation products by LCHRMS. N-nitroso-CIP accounted for 14.3% of the initial CIP concentration (20 µg/L) and accumulated against time. The use of 4,5-diaminofluorescein diacetate and superoxide dismutase as scavengers for in situ production of nitric oxide and superoxide radical anion respectively, revealed that the mechanisms of formation of N-nitroso-CIP likely involved a nitrosation pathway through the formation of peroxynitrite and another one through codenitrification processes, even though the former one appeared to be prevalent. This work extended the possible sources of N-nitrosamines by including a formation pathway relying on nitric oxide reactivity with secondary amines under activated sludge treatment.Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) were investigated from effluent of two hospital and two municipal wastewater treatment plants (WWTPs) before and after disinfection. The results of network analysis showed that 8 genera were identified to be the main potential hosts of ARGs, including Mycobacterium, Ferruginibacter, Thermomonas, Morganella, Enterococcus, Bacteroides, Myroides and Romboutsia. The removal of ARGs and their possible bacterialhosts were synchronous and consistent by chlorine or ultraviolet (UV) disinfection in WWTPs. The mechanisms of ARB and ARGs removal, and conjugation transfer of RP4 plasmids by UV, chlorine and synergistic UV/chlorine disinfection was revealed. Compared to UV alone, ARB inactivation was improved 1.4 log and photoreactivation was overcomeeffectively by UV/chlorine combination (8 mJ/cm2, chlorine 2 mg/L). However, ARGs degradation was more difficult than ARB inactivation. Until UV dosage enhanced to 320 mJ/cm2, ARGs achieved 0.58-1.60 log removal. Meanwhile, when 2 mg/L of chlorine was combined with UV combination, ARGs removal enhanced 1-1.5 log. The synergistic effect of adding low-dose chlorine (1-2 mg/L) during UV radiation effectively improved ARB and ARGs removal simultaneously. The same synergistic effect also occurred in the horizontal gene transfer (HGT). Non-lethal dose chlorine (0.5 mg/L) increased the conjugation transfer frequency,which confirmed that the mRNA expression levels of type IV secretion system (T4SS) proteins vir4D, vir5B and vir10B were significantly enhanced. The risk of RP4 plasmid conjugation transfer was significantly reduced with UV/chlorine (UV ≥ 4 mJ/cm2, chlorine ≥ 1 mg/L). These findings may serve as valuable implications for assessing and controlling the risk of ARGs transfer and propagation in the environment.