Occurrence, distribution, and risk assessment of quinolone antibiotics in municipal sewage sludges throughout China.

A nationwide study of the occurrence, distribution, potential drivers, and ecological risks of 24 quinolone antibiotics (QNs) in 74 Chinese sludge samples from 48 wastewater treatment plants (WWTPs) was conducted. In domestic sludge, the ∑QNs concentrations were  3rd-generation QNs > 4th-generation QNs > 1st-generation QNs. Meanwhile, abundant veterinary and human/veterinary quinolones (

Non-radical dominated degradation of bisphenol S by peroxymonosulfate activation under high salinity condition: Overlooked HOCl, formation of intermediates, and toxicity assessment.

Extensive studies revealed that Cl- could inhibit the removal of targeted pollutants under low Cl- conditions in the peroxymonosulfate (PMS) system. However, the enhanced effect of Cl- has always been overlooked under high Cl- conditions. Here, we find that high concentration of Cl- played a critical role in bisphenol S (BPS) degradation by activating PMS using 16%-CoFe2O4@PAL (16%-CFO@PAL). The removal of BPS was sharply enhanced after introducing 0.5 and 1.0 M Cl-, and the corresponding kobs increased to 0.922 min-1 and 1.103 min-1, which was 6-fold and 7-fold higher than the control (0.144 min-1), respectively. HOCl was demonstrated as the dominant species for removing BPS in 16%-CFO@PAL/PMS system under high Cl- circumstances. The typical chlorinated BPS intermediates were identified, which showed higher eco-toxicity than BPS. The chlorinated byproducts along with their toxicity could be effectively eliminated after 30 min. The possible formation mechanism of chlorinated products was further revealed by theoretical calculations. Toxicity assessment experiments showed that BPS significantly affected hormone levels of zebrafish and showed toxicity on the testis and liver of zebrafish, which could be reduced using 16%-CFO@PAL/PMS system. This study attracts attention to the overlooked HOCl in PMS-based processes under high salinity conditions.

The spatiotemporal distribution and potential risk assessment of 19 phthalate acid esters in wastewater treatment plants in China.

The spatiotemporal distribution of phthalate acid esters (phthalates, PAEs) in wastewater treatment plants (WWTPs) in China was studied. The concentration of PAEs in influent and effluent increased from 2009 to 2016, indicating that the exposure level of PAEs in China increased continuously. Although the concentration of PAEs in sewage sludge in China ranged from 33.3 to 298 ug/g, there was no obvious spatial distribution pattern. Among the 19 PAE homologues, DEHP, DnBP, and DIBP were the most abundant phthalates detected in wastewater and sludge. Ecological risk assessment confirmed that there was a high chronic and acute risk of DIBP in effluent since 2015. Therefore, this study highlights the need for further studies on the exposure and toxicology of DIBP. Dietary intake accounted for more than 98% of the total risk, indicating that the risk of sludge application in agricultural land was much higher than that in nonagricultural land. The results from this study will provide valuable information for the safe disposal of sludge and wastewater.

Selective and efficient removal of Hg (II) from aqueous media by a low-cost dendrimer-grafted polyacrylonitrile fiber: Performance and mechanism.

Polyacrylonitrile fiber was successfully modified with triazine-based dendrimer via grafting method as a promising adsorbent for removal of mercury species from aqueous media. The prepared adsorbent was characterized by elemental analysis, scanning electron microscope, Fourier transform infrared spectroscopy, porous structure analysis and X-ray photoelectron spectroscopy, providing the evidence of successful fabrication. The adsorption conditions were found via varying pH, dosage, coexisting substances, contact time, temperature and concentration. Adsorption performance, described better by the pseudo-second-order kinetics with intraparticle diffusion as rate controlling step and Langmuir isotherm model, indicated a chemisorption process with the maximum Langmuir adsorption amount of 227.64 mg g-1 for mercury ions. Thermodynamically, adsorption of mercury ions was spontaneous and endothermic. Desorption and regeneration experiments demonstrated that it could be reused in five successive adsorption cycles without significant loss of its original performance. Experimental data and density functional theory calculation disclosed the coordination geometries and chelating mechanism between the adsorbent and mercury ions. The proposed study would provide a new prospect for the purification of mercury in aqueous system by functionalizing commercial polyacrylonitrile fiber with dendrimers.

Occurrence, composition profiles and risk assessment of polycyclic aromatic hydrocarbons in municipal sewage sludge in China.

A nationwide survey, including 75 sludge samples and 18 wastewater samples taken from different wastewater treatment plants (WWTPs) from 23 cities, was carried out to investigate the occurrence and composition profiles of polycyclic aromatic hydrocarbons (PAHs) in China. In total, the concentrations of ∑16PAHs in sludge ranged from 565 to 280,000 ng/g (mean: 9340 ng/g) which was at a moderate level in the world. The composition profiles of PAHs were characterized by 3- and 4-ring PAHs in textile dyeing sludge and 4- and 5-ring PAHs in domestic sludge. Significant variations in regional distribution of PAHs were observed. Both the principal components analysis and diagnostic ratios revealed that vehicle exhaust, coal and natural gas combustion were the main sources of PAHs in China. The estimated concentrations of PAHs were 3820 ng/L and 1120 ng/L in influents and effluents of the WWTPs, respectively. The high toxic equivalent quantity (TEQ) values of PAHs are ascribed to the high PAH levels. Risk quotient values (RQs) in sludge indicated that there was low potential risk to soil ecosystem after sludge had been applied one year except for indeno [1,2,3-cd]pyrene (IcdP) detected in Huaibei, Anhui province.

Profiles and risk assessment of phthalate acid esters (PAEs) in drinking water sources and treatment plants, East China.

This study is the first report describing the occurrence of 15 phthalate acid esters (PAEs) in the three typical water sources of YiXing City, Taihu Upper-River Basin, East China. The fate of target PAEs in the Jiubin drinking water treatment plant (JTP) was also analyzed. The amounts of Σ15PAE in the Hengshan (HS), Youche (YC), and Xijiu (XJ) water sources were relatively moderate, with mean values of 360, 357, and 697 ng L-1, respectively. Bis(2-ethylhexyl) phthalate (DEHP) dominated the PAE concentration, making up 80% of the 15 total PAEs. The highest levels of Σ15PAE were found in HS, YC, and XJ in March 2015, January 2015, and July 2014, respectively. The occurrence and concentrations of these compounds were spatially dependent, and the mean concentrations of Σ15PAE in HS, YC, and XJ samples increased from the surface layer to the bottom layer with varied percentage increases. The removal efficiency of the PAEs in the finished water varied markedly, and the removal of PAEs by the JTP ranged from 12.8 to 64.5%. The potential ecosystem risk assessment indicated that the risk of PAEs was relatively low in these three water sources. However, risks posed by PAEs due to drinking water still exist; therefore, special attention should be paid to source control in the JTP, and advanced treatment processes for drinking water supplies should be implemented.

Removal of phosphate from secondary effluent with Fe2+ enhanced by H2O2 at nature pH/neutral pH.

Removal of phosphate in secondary effluents was investigated in presence of Fe(2+)/H(2)O(2). The effect of H(2)O(2)-dose, Fe-dose and initial phosphate concentration were assessed. The results indicated that Fe(2+)/H(2)O(2) could greatly increase the removal of phosphate compared with those achieved by Fe(2+) alone. For initial phosphate concentration of 0.97-3.75 mg P/L, phosphate removal rates of 50-60% were observed at 1:1 molar addition of Fe(II). However, a 125% excess of Fe-dose was necessary for complete phosphate removal. The experimental data demonstrated that removal of phosphate with Fe(2+)/H(2)O(2) was higher than that observed with ferric coagulation alone. This fact suggested that in situ formed Fe(III) having much affinity for ligand phosphate. Chemical co-precipitation was considered as the dominant mechanism about phosphate removal in presence of Fe(2+)/H(2)O(2). The electron paramagnetic resonance (EPR) spectra tests in secondary effluents showed that Fe(2+)/H(2)O(2) could produce an increasing hydroxyl radical concentration with a decrease in both H(2)O(2) dosage and phosphate concentration. Fe(2+)/H(2)O(2) had the potential to be utilized for removal of phosphate due to the lower cost and the higher phosphate removal capability.