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•Hydrothermal synthesis of magnetic sludge biochar was used to remove TC and CIP.•Fe/Zn-SBC had the stable adsorption capacity and good safety in a wide pH range.•Physical and ...chemical mechanism were involved in TC and CIP adsorption.•The co-processing of ultrasound and ethanol could effectively regenerate Fe/Zn-SBC.•Resource utilization of sludge and antibiotics removal were simultaneously obtained.
In this study, biochar derived from municipal sludge was activated by zinc chloride, which was first time used as the precursor for hydrothermal synthesis of magnetic sludge biochar (Fe/Zn-SBC) for tetracycline (TC) and ciprofloxacin (CIP) removal. The maximum adsorption capacity of Fe/Zn-SBC for TC and CIP were 145 mg g−1 and 74.2 mg g−1 at 25 °C, respectively. Kinetics, isotherms, thermodynamics and characterization analysis suggested that the adsorption process was dominated by pore filling, oxygen-containing groups complexation, π-π conjugation and hydrogen bonding. Fe/Zn-SBC had the high selective adsorption capacity for TC and CIP in a wide pH range and even at the high ionic strength. The magnetic sensitivity ensured its easy separation performance. The co-processing of ultrasound and ethanol could effectively regenerate the used Fe/Zn-SBC. Also, it exhibited great environmental safety in the pH range of 3 to 12. These superiority suggested that it is a promising adsorbent for antibiotics removal.
This study conducted the first extensive and comprehensive investigation of the whole-scale sedimentary antibiotic concentration, possible drivers, environmental fate, and potential ecological risks ...in the Yangtze River. Totally, 20 antibiotics were detected in the sediments. Results revealed that the order of antibiotic abundance in sediment was fluoroquinolones > tetracyclines > macrolides > sulfonamides > amphenicols. The total antibiotic concentrations were 0.10–134.4 ng/g (mean: 11.88 ng/g). Of these, fluoroquinolones and tetracyclines were the two dominant antibiotic categories. The dominant occurrence of fluoroquinolones and tetracyclines in sediments suggested that the distribution coefficient (K d) was one of the important factors to determine their fate. Correlation analysis demonstrated that antibiotic contamination was largely influenced by the local scale of animal husbandry, and the positive correlation between antibiotics and heavy metals was likely driven by their common source of contamination and the complexation. Environmental risk assessment showed that tetracycline and chlortetracycline exhibited potential risks from medium to high in the Yangtze River, although most of the compounds posed minimal and low risks. This work provided a valuable large-scale data set across the whole Yangtze River and revealed the contamination profile of antibiotics. Mitigation and management measures to reduce antibiotic inputs are needed for the Yangtze River basin.
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•The present activation methods of persulfate oxidation of PFOA and PFOS are reviewed.•Operational factors influencing the removal efficiency are discussed and summarized.•Reaction ...mechanisms and practical feasibility of PFOS and PFOA are evaluated and outlined.•Knowledge gaps and research needs of PFOS and PFOA degradation are proposed.
Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) have attracted global attention due to their chemical durability, wide distribution, biotoxicity and bioaccumulative properties. Persulfate is a promising alternative to H2O2 for advanced oxidation processes and effective for organic removal. In this review, persulfate activation methods and operational factors in persulfate-based PFOA / PFOS degradation are analyzed and summarized. Moreover, the decomposing mechanisms of PFOA and PFOS are outlined in terms of molecular structures based a series of proposed pathways. PFOS could be converted to PFOA with the attack of SO4− and OH. And then PFOA defluorination occurs with one CF2 unit missing in each round and the similar procedure would occur continuously with sufficient SO4− and OH until entire decomposition. In addition, several knowledge gaps and research needs for further in-depth studies are identified. This review provides an overview for better understanding of the mechanisms and prospects in persulfate-based degradation of PFOA and PFOS.
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•The synergistic influences of US and PS are reviewed.•Operational factors influencing the removal efficiency are discussed and summarized.•Reaction mechanisms of sono-activated ...persulfate oxidation are evaluated and outlined.•Knowledge gaps and research needs of sono-activated persulfate are proposed.
Persulfate (PS) has attracted great attention as an alternative to H2O2 for advanced oxidation processes in recent years. Among various activation techniques, ultrasound (US) activation acts as an emerging method and has gained increasing interest especially in recent years. The combination of US and PS is a promising alternative for organic wastewater treatment. In this review, the synergistic effects of US and PS were investigated based on wide applications. The degradation efficiency is easily influenced by the reaction factors, including ultrasonic power and frequency, pH, temperature, PS concentration, and coexisting inorganic anions etc. These factors were summarized and analyzed to give the optimal references for further in-depth studies. Moreover, the decomposing mechanisms are outlined in terms of molecular structures due to the one-sidedness of reactive radical analysis. In the end, the concluding remarks and perspectives are made for future study on US-PS technologies. This review can provide an overview for the systematic understanding of the mechanisms and synergistic effects of US and PS combination.
•An integrated framework was proposed for identifying resistome risk and ecological processes.•Abundant and diverse resistome, mobilome and virulome were detected in the lake sediments.•ARG diversity ...was mainly explained by the spatial turnover rather than nestedness.•Stochastic processes played higher contribution than deterministic processes on the ARG profiles.•Homogenizing dispersal, homogeneous selection and ecological drift were the dominators.
The increasing prevalence of antibiotic resistance genes (ARGs) in aquatic environments has attracted considerable concerns due to their potential threat to public health. For reducing environmental risk of ARGs, it is crucial to identify the pathogenic resistant bacteria, determine the driving forces governing the ARG community and apportion their sources, which is yet remained to explore. In this study, we developed a framework integrating high-throughput sequencing (HTS) analyses, null-model-based methods and machine-learning classification tool for understanding the environmental resistome risk and the ecological processes that control the ARG profile in aquatic sediments, and applied to two urban lakes (Lake Tai and Lake Baiyang) in China. The HTS-based metagenomic analyses revealed abundant and diverse resistome, mobilome and virulome in the two lakes, including some emerging ARGs such as mcr and carbapenemases types. Relatively, the diversities for ARGs, mobile genetic elements (MGEs) and virulence factor genes in Lake Baiyang were significantly higher than those in Lake Tai (p < 0.05). The metagenomic assembly and binning approaches tracked a number of potential pathogenic antibiotic resistant bacteria and found the co-occurrence of ARGs, MGEs and human bacterial pathogens in ~50% of the sediment samples, indicating a substantial resistome risk in the lakes. Comparison of multiple-site beta-diversity dissimilarity indexes suggested the ARG diversity was mainly explained by the spatial turnover rather than nestedness and exhibited significant distance-decay pattern. The results of using a novel null-model-based stochasticity ratio showed the stochastic processes made a higher contribution than the deterministic processes on the ARG profile in the environment, especially for Lake Baiyang (>65%). This was confirmed by the determination analyses of various ecological processes on ARG community by utilizing the null-model-based statistical framework for quantifying community assembly. That is, homogenizing dispersal (40%) dominated in Lake Baiyang, followed by homogeneous selection (32%) and ecological drift (15%), while ecological drift (33%) and homogenizing dispersal (31%) were the dominators in Lake Baiyang. SourceTracker analysis showed human sewage-associated sources were the largest contributor (~62%) of ARGs in the environment. The findings shed light on the dissemination risk and driver dynamics of antimicrobial resistance in the aquatic environment, which may help to make effective management strategies for controlling pollution of ARGs.
Current and historic pesticide use has potential to compromise e.g. drinking water sources due to both primary and secondary emission sources. Understanding the spatial and temporal dynamics of ...emissions might help inform management decisions. To explore this potential; water, sediment and soil samples were concurrently collected from the River Ugie, Scotland over four seasons. Occurrence and fate of nine pesticides including four historic-use pesticides (HUPs): simazine, atrazine, isoproturon and permethrin, and five current-use pesticides (CUPs): metaldehyde, chlorpyrifos, chlortoluron, epoxiconazole and cypermethrin were analysed. Concentrations of target pesticides in water, sediments and soils were 4.5–45.6 ng·L−1, 0.9–4.6 ng·g−1 dw (dry weight) and 1.7–8.0 ng·g−1 dw, respectively. Concentrations of pesticides in water were found to significantly differ between seasons (p < 0.05). Significant differences in pesticide concentrations also occurred spatially within sediments (p < 0.01), indicating spatial and temporal associations with pesticide use. Sediment-water exchange showed that the sediment acts as an important secondary emission source particularly for the HUPs, while current local application and sediment emission are both major driving forces for CUPs in the riverine environment. These findings were supported by concentration ratios between different media, which showed potential as a preliminary assessment tool for identifying the source of pollutants in aquatic environments.
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•Nine pesticides in a Scottish priority catchment were investigated.•Concentrations of CUPs and HUPs in water, sediment and soil were determined.•Seasonal and temporal variations were associated with pesticides use.•Sediment-water exchange can be used to identify the source or sink of pesticides.•Concentration ratios between different media were used to trace the input pathway.
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It is widely recognised that inadequate removal of pharmaceuticals in wastewater may lead to their presence in surface waters. Hospitals are key point-sources for pharmaceuticals ...entering municipal waterways, and rural hospitals are of concern as receiving wastewater treatment plants (WWTPs) may be smaller, less advanced and thus less efficient. While most research has focused on urban settings, here we present results from a rural ‘'source-to-sink’' study around a hospital. The aim was to determine the contribution of pharmaceuticals discharged to a municipal wastewater system, and, to assess pharmaceutical removal efficiency in the WWTP. Samples were collected daily for one month to assess water quality and pharmaceuticals in the broader water cycle: (i) raw water supply; (ii) treated hospital tap water; (iii) hospital wastewater discharge; (iv) combined WWTP influent; and (v) final WWTP effluent. Target compounds included analgesics/antiinflammatories, antibiotics, psychiatric drugs, and a synthetic estrogen hormone. Concentrations ranged from: 3 ng/L (carbamazepine) to 105,910 ng/L (paracetamol) in hospital discharge; 5 ng/L (ibuprofen) to 105,780 ng/L (paracetamol) in WWTP influent; and 60 ng/L (clarithromycin) to 36,201 ng/L (paracetamol) in WWTP effluent. WWTP removal ranged from 87% (paracetamol) to <0% (carbamazepine and clarithromycin), and significant correlations with water quality characteristics and WWTP flow data were observed for some compounds. Results suggested that the hospital is an important source of certain pharmaceuticals entering municipal wastewater, and associated water quality parameters are impacted. Pharmaceutical persistence in the WWTP effluent highlighted the direct pathway these compounds have into receiving surface water, where their impact remains uncharacterised. Rural regions may face future challenges mitigating environmental risk as WWTP infrastructure ages, populations grow and pharmaceutical use and diversity continue to increase.
•Less advanced wastewater treatment plants may treat rural hospital wastewater.•Study of pharmaceuticals and water quality in hospital and municipal wastewater.•Focus on ‘source-to-sink’ system from raw water supply to final treated effluent.•Significant pharmaceutical concentrations in hospital discharge and treated effluent.•Environmental impact of pharmaceuticals remains uncharacterised in rural regions.
Passive sampling is highly complimentary to spot sampling in environmental analysis. A polar organic chemical integrative sampler (POCIS) was extensively tested to optimize its performance under both ...controlled and field conditions. The passive sampler was subsequently used for the sampling and analysis of estrone, 17β-estradiol, 17α-ethynylestradiol, bisphenol A, propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, indomethacine, diclofenac and meclofenamic acid in sewage effluent and river water. Under laboratory conditions, the kinetics of compound uptake by POCIS were linear during 10-day of exposure. POCIS sampling rates of the target compounds were significantly greater by using polyethersulfone instead of polysulfone membrane, and enhanced with increasing sorbent exposure area. Together with spot water sampling, the optimized POCIS was deployed in the River Ouse, West Sussex, UK to obtain field-derived sampling rates which, for endocrine disrupting chemicals (EDCs), were significantly higher than those from laboratory experiments. Both spot and passive sampling demonstrated that most of the target chemicals were frequently detected in sewage effluent and river waters, and that the daily changes in the pollutant concentrations were greater for pharmaceuticals than for EDCs. The aqueous concentrations of all compounds were elevated at a sewage outfall, which is confirmed to be an important source of the target compounds in the river. The validated POCIS was then successfully used to estimate the concentrations of the target compounds in effluent and river water, which were in good agreement with those from spot sampling for pharmaceuticals.
Tonghui River, a typical river in Beijing, People's Republic of China, was studied for its water and sediment quality, by determining the levels of 16 polycyclic aromatic hydrocarbons (PAHs), 12 ...polychlorinated biphenyls (PCBs) and 18 organochlorine pesticides in water and sediment samples. Total PAHs, PCBs and organochlorine pesticides concentrations in water varied from 192.5 to 2651 ng/l, 31.58–344.9 ng/l and 134.9–3788 ng/l, respectively. The total PAHs, PCBs and organochlorine pesticides concentrations in surficial sediments were 127–928 ng/g, 0.78–8.47 ng/g and 1.79–13.98 ng/g dry weight, respectively. The results showed that the concentration of these selected organic pollutants in sediment was higher than those in surface water. It may be due to the fact that organic hydrophobic pollutants tend to stay in the sediments. The PAHs were dominated by 2-, 3-ring components in water samples and by 3- and 4-ring compounds in sediment. For organochlorines, α-HCH, δ-HCH, Heptachlor, Endosulfan II, DDT are the major organochlorine pesticides in water while Heptachlor, Dieldrin and DDE composed of 95% of total organochlorine pesticides in sediment. For HCHs (HCHs=α-HCH+β-HCH+γ-HCH+δ-HCH), the predominance of α-HCH of total HCHs were clearly observed in water and sediment. PCB18, PCB31 and PCB52 were predominant in water, on average these compounds collectively accounted for 67% of total PCBs. But in sediment, the predominant compounds were PCB28, PCB31 and PCB153, which accounted for 71% of total PCBs in sediment. The levels of micro pollutants in our study areas were compared with other studies.
Organic pollutants were higher in sediments than in surface waters.
A novel approach was employed to load α-Fe2O3 and α-FeOOH onto sewage sludge biochar (SBC) with the purpose of efficient nickel (Ni) removal. A high Ni(II) adsorption capacity of 35.50 mg·g-1 in 100 ...ppm Ni(II) solution with 10 mg modified sewage sludge biochar (MSBC) was achieved. The adsorption kinetic and isotherm were fitted well by the pseudo-second-order model and the Langmuir model, respectively. The optimal pH was found around a neutral pH of 7. The adsorption mechanisms of Ni(II) onto MSBC were described as the synergistic effects of electrostatic attraction, ion exchange, inner-sphere complexation and co-precipitation. The initial rapid adsorption phenomenon could be attributed to electrostatic attraction and ion exchange, and then inner-sphere complexation and co-precipitation acted as a crucial role in the following step. The remarkable performance of MSBC provides an effective waste utilization approach to simultaneous sewage sludge recycle and Ni removal from aqueous solution.
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