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Chlorine-resistant bacteria (CRB) in drinking water treatment plants (DWTPs) jeopardize water quality and pose a potential risk to human health. However, the specific response of CRB to chlorination and chloramination remains uncharacterized. Therefore, we analyzed 16 S rRNA sequencing data from water samples before and after chlorination and chloramination taken between January and December 2020. Proteobacteria and Firmicutes dominated all finished water samples. After chloramination, Acinetobacter, Pseudomonas, Methylobacterium, Ralstonia, and Sphingomonas were the dominant CRB, whereas Ralstonia, Bacillus, Acinetobacter, Pseudomonas, and Enterococcus were prevalent after chlorination. Over 75% of the CRB e.g. Acinetobacter, Pseudomonas, Bacillus, and Enterococcus were shared between the chlorination and chloramination, involving potentially pathogens, such as Acinetobacter baumannii and Pseudomonas aeruginosa. Notably, certain genera such as Faecalibacterium, Geobacter, and Megasphaera were enriched as strong CRB after chloramination, whereas Vogesella, Flavobacterium, Thalassolituus, Pseudoalteromonas, and others were enriched after chlorination according to LEfSe analysis. The shared CRB correlated with temperature, pH, and turbidity, displaying a seasonal pattern with varying sensitivity to chlorination and chloramination in cold and warm seasons. These findings enhance our knowledge of the drinking water microbiome and microbial health risks, thus enabling better infectious disease control through enhanced disinfection strategies in DWTPs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

People who engage in water sports in recreational marine water may be at high risk of exposure to hazardous antibiotic-resistant bacteria (ARB). However, information on the contribution of specific sources to ARB contamination in recreational marine water is still lacking. Here, we carried out monthly analyses of antibiotic resistance genes (ARGs), pathogenic bacteria and 16S rRNA sequencing data at the First Bathing Beach in Qingdao. The sampling sites were divided into four areas: swimming area, intermediate area, polluted area, and sewage outlet. Correlations between ARGs and bacterial communities among sampling sites were explored by spatial and temporal analysis. We found that all of 21 important ARG types were detected in the swimming area, with aadA (1.3 × 10 6  ± 2.7 × 10 6 genomic copies/L) and sul2 (4.3 × 10 5  ± 5.9 × 10 5 genomic copies/L) at the highest concentration. Most ARGs were detected at highest frequency and concentration in the sewage outlet and decreased from there to the swimming area. ARG correlation between these two areas was positive only in the cold season, suggesting that sewage was the main source of ARG pollution in the swimming area during that period. The ARGs ermA(1) and vanA were detected at highest frequency and concentration in the swimming area and were significantly correlated with the intestinal pathogen Enterococcus, which was more abundant here than in the surrounding areas during the warm season. Co-occurrence analysis of bacterial genera and ARGs showed that six genera were commonly correlated with ARGs in all sampling areas in the cold season, while none were found in the warm season. Our findings indicate that ARG pollution in the swimming area was also driven by sources other than sewage, especially in the warm season, which is the peak tourist season in Qingdao. These results provide a valuable basis for the implementation of effective strategies to control ARG risks in recreational waters., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Antibiotics are known to be key drivers of antibiotic resistance and antibiotic resistance gene transmission. However, the contribution of the emerging pollutant metformin in facilitating antibiotic resistance remains unclear. In this study, Escherichia coli K12 (E. coli) was exposed to metformin at concentrations ranging from 10 -7 to 200 mg/L, and antibiotic susceptibility test of isolated mutants was evaluated. DNA and RNA sequencing and real-time quantitative PCR (qPCR) were performed to identify the underlying mechanisms. The results showed metformin concentrations ranging from 10 -6 to 200 mg/L caused multiple-antibiotic resistance in E. coli. After 1 day exposure to metformin at 1 ng/L, the mutation frequency in E. coli increased to 1.24 × 10 -8 , and it further increased to 7.13 × 10 -8 when prolonged to 5 days. And the mutants showed multiple-antibiotic resistance. Whole-genome DNA analysis of mutants showed chromosome mutagenesis in marR, tonB, and fhuA. Global transcriptional analysis and qPCR revealed the expressions of emrK, emrY, cusB, cusC, hycA, cecR, marA, acrA, and acrB were upregulated and those of tonB and fhuA were significantly downregulated. Thus, an increase in efflux systems AcrAB-TolC, EmrKY-TolC, and CusCFBA together with a decrease in FhuA-TonB protein complex play vital roles in the multiple-antibiotic resistance induced by metformin., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Electro-dewatering of sludge has received considerable attention due to its low energy consumption for sludge deep-dewatering. However, prior studies have shown the resistance of dried sludge near anode significantly hinders electro-dewatering. The dewatering performance may be improved by reducing the resistance with the addition of conductive material into sludge. We conditioned municipal sludge by anthracite powder, an inexpensive product, to increase solid conductivity, followed by electro-dewatering. After running for 20 min under a constant voltage of 30 V, when the anthracite powder mass was 10%-22% of raw sludge dry solids mass (DS), the final dry solids content of the mud cake after dehydration was 6.2%-12.9% higher than that from dehydration of unconditioned sludge. The average filtrate flow rate ranged from 0.0243 to 0.0285 g s -1 . The lowest unit energy consumption, 0.19 kW h·kg water -1 , which was 14% lower than that of control, was reached when 18% DS of anthracite was added. Our theoretical analysis indicates that properly increasing solid conductivity of sludge can reduce the adverse effect caused by the high electrical resistance of sludge near anode. The experimental results, along with the theoretical analysis, show that using anthracite powder for sludge modification is an economical approach to improve sludge dewatering rate and reduce energy consumption., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Preterm infants constitute an important proportion of neonatal deaths and various complications, and very preterm infants (VPI) are more likely to develop severe complications, such as intraventricular hemorrhage (IVH), anemia, and sepsis. It has been confirmed that placental transfusion can supplement blood volume in infants and reduce preterm-associated complications, which is further conducive to the development of the nervous system and a better long-term prognosis. Based on these advantages, placental transfusion has been widely used in VPI. There are three main types of placental transfusion: delayed cord clamping (DCC), intact umbilical cord milking (I-UCM), and cut umbilical cord milking (C-UCM). However, the optimal method for PT-VPI remains controversial, and it is urgent to identify the best method of placental transfusion. We plan to fully evaluate the safety and effectiveness of these three placental transfusion methods in VPI in a 3-arm multicenter randomized controlled trial: Placental Transfusion in Very Preterm Infants (PT-VPI). Trial registration: chictr.org.cn, number ChiCTR2000030953., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The efficiency of common sludge electro-dewatering (EDW) is restrained by the following issues: 1, the near-anode sludge dries out quickly, causing a rapid increase in electrical resistance; 2, the pH at anode decreases by the accumulation of H + from the electrolysis of moisture, resulting in a decrease in Zeta potential (ζ). Alleviating the negative impact of these problems is the key to improving the dewatering efficiency of EDW. Therefore, in this study, calcium oxide (CaO) was used for near-anode sludge modification to increase its pH and electrical conductivity. With increasing CaO dosage, pH rose from 6.0 to 12.2, electrical conductivity increased from 368 ± 16 μS/cm to 6285 ± 21 μS/cm and the ζ declined from -15.3 ± 0.6 mV to -8.8 ± 0.4 mV. The EDW tests were conducted at 30 V and 25.5 kPa. The results indicate near-anode sludge modification with CaO weighing 3%-5% mass of raw sludge (m u(RS) ) improved the EDW effect, while the energy consumption increased slightly. When 3%-5% m u(RS) of CaO was added, the final moisture content of sludge was 54.5%-44.3%, below that of the blank group (no CaO added), which was 57.9%; the time to obtain target moisture content (60%) was 910 s-590 s, lower than the blank group's 1060 s; and the energy consumption to obtain target moisture content was 0.233 kW h/kg H 2 O-0.271 kW h/kg H 2 O, higher than the blank group's 0.157 kW h/kg H 2 O. A quantitative criterion (Ksi EDW ) was adopted to assess the feasibility of EDW. Economically and energetically, the experiment with 4% m u(RS) of CaO added for near-anode modification was the optimal condition in this research, due to its second smallest Ksi EDW , the best sludge reduction effect (67.2%), lower final moisture content (46.2%) and less time (640 s) to obtain target moisture content. The results show some mechanisms of EDW and provide experience for practical application., Competing Interests: Declaration of competing interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

In this study, mechanically-dewatered sludge was used to investigate the effect of electro-dewatering (EDW) under two electrical modes, which are constant current mode followed by constant voltage mode (CV-EDW), and constant voltage mode followed by constant current mode (VC-EDW). The effect of current and voltage changes on dewatering efficiency and energy consumption of sludge electroosmosis under CV-EDW and VC-EDWs was evaluated The results show that compared with constant current mode (C-EDW), CV-EDW can improve the final dry solids content and reduce the heating rate, and the final dry solids content and unit energy consumption increase with the decrease of current and the increase of voltage. Under CV-EDW, when the dry solids content is 32%, the energy consumption can be reduced by changing to the constant voltage stage, and the energy consumption is 0.093-0.113 kWh/kg water . Compared with constant voltage mode (V-EDW), VC-EDW significantly improves sludge dewatering rate. Under VC-EDW, the final dry solids content of sludge increases with the decrease of current and voltage. When the voltage is decreased by 10 V, the unit energy consumption is reduced by 27.15 ± 1.77% on average, and the energy consumption is 0.132-0.163 kWh/kg water . Compared with CV-EDW, the dehydration rate of VC-EDW is increased by 72.9% on average. However, the unit energy consumption required for dehydration increases by 43.09% when the dry solids content is less than 45%., (Copyright © 2019 Elsevier B.V. All rights reserved.)