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Abstract: In this study, aerobic granules were cultivated in sequencing batch reactors with activated sludge as the seed. The reactors were operated for 12h per cycle with the organic loading rate (OLR) increasing in double stepwise from 0.5 to 4.0g COD L−1 d−1. Within the 40 d running, black granules with regular and smooth morphology were cultivated, which had high wet density and high settling velocity. During the granulation process, foams emerged and disappeared in the reactor, coinciding with the proliferation of filamentous microorganisms in the granules, implying that surfactants might exist and play an important role in the granulation. Using ultra performance liquid chromatography–tandem mass spectrometry, the surfactants were identified as homologous compounds of polyethylene glycol (PEG) with molecular weights ranging mainly from 100 to 500Da. Their general formulas were proposed as HO–[CH2–CH2–O] n –H. The source of PEG still needs further investigation. [ABSTRACT FROM AUTHOR]

Abstract: The effects of extracellular polymeric substances on aerobic granulation in sequencing batch reactors were investigated by evaluating the content and compositions of extracellular polymeric substances, and the relationship between extracellular polymeric substances composition and surface properties of glucose-fed aerobic granules. The results showed that extracellular polymeric substances could affect surface properties of cells, such as surface charge and hydrophobicity, enhance polymeric interaction and promote aerobic granulation. Moreover, extracellular polymeric substances were produced mainly in the exponential phase, and served as carbon and energy source in starvation phase during granulation process, thus regulating the growth of bacteria in the interior and exterior of granules, and maintaining the integrality of granules. [Copyright &y& Elsevier]

In this study, twenty-four core sediment samples were collected from monitoring stations in the East China Sea (ECS) to investigate the spatial and temporal distributions of polybrominated diphenyl ethers (PBDEs) and their potential sources. In surface sediment samples (the top 0–3 cm segment), the concentrations of Σ 8 PBDEs (sum of BDE15, 28, 47, 99, 100, 153, 154 and 183) and BDE209 were between 0.03 and 1.26 ng g −1 d.w., and 0.20 and 3.15 ng g −1 d.w., respectively. The PBDEs concentrations were decreased generally from the shore towards the sea, indicating that PBDEs are mainly derived from anthropogenic sources. As the predominant congener, BDE209 was primarily distributed in the nearshore regions, suggesting that it might be derived from runoff and sewage. In contrast, higher levels of BDE99 and BDE47 were detected in the offshore samples, and the concentrations of BDE47 were higher than those of BDE99. All of their concentrations were poorly correlated with TOC, suggesting BDE47 and BDE99 might be transferred mainly along with the atmosphere. In most sediment cores, the Σ 8 PBDEs and BDE209 concentrations increased from the bottom (18–30 cm), reached their maximum concentrations in the middle (6–15 cm) or upper (0–6 cm) sections, and leveled off near the surface (0–3 cm). This trend is consistent with the phasing-out of PBDEs and the strict management of recycling e-waste. This is the first study for network used to analyze the distribution properties of pollutant congeners in environment, which facilitates the visualization of cluster results among multivariable data and helps in tracing the potential sources of pollutants. [ABSTRACT FROM AUTHOR]

The leakage of landfill leachate (LL) into environmental media would be happened even in the sanitary/controlled landfill, due to the deterioration of geomembrane and the blockage of drainage system after long-term operation. Considering the complex composition and high concentration of pollutants in LL, its toxicity assessment should be conducted as a whole liquid contaminant. Therefore, the impacts of LL on Caenorhabditis elegans (C. elegans) were investigated under the condition of different exposure time and exposure volume fraction (EVF). The stimulating effects on locomotion behavior and growth of C. elegans were observed after acute (24 h) exposure to LL, which were increased firstly and then decreased with the increase of EVF. Meanwhile, the intestinal barrier was not affected by LL, and levels of reactive oxygen species (ROS) and cell apoptosis significantly decreased. However, stimulation and inhibition effects on locomotion behavior and growth of C. elegans were observed when subacute (72 h) exposure to 0.25%–0.5% and 1%–4% of LL, respectively. The intestinal injury index and levels of ROS and cell apoptosis significantly increased when EVF were 2% and 4%. Although the acute exposure of LL had resulted in obviously biological adaptability and antioxidant defense in C. elegans , the protective mechanisms failed to be induced as the exposure time increased (subacute exposure). The toxic effects were confirmed by the down-regulation of genes associated with antioxidant defense and neurobehavior, accompanied by the up-regulation of intestinal injury and cell apoptosis related genes. Moreover, the disturbance of metabolic pathways that associated with locomotion behaviors, growth, and antioxidant defense provided good supplementary evidence for the confirmation of oxidative stress in C. elegans. The research results verified the potential of C. elegans as model organism to determine the complex toxic effects of LL. [Display omitted] • Acute expose to landfill leachate (LL) can active antioxidant defense of C. elegans. • Protective mechanisms failed to be induced when subacute exposure to LL. • The toxic effects of LL were confirmed by the expression change of related genes. • Disturbances in metabolic pathway confirm oxidative stress response of C. elegans. • Metabonomic results verify the response of phenotypic and molecular indexes. [ABSTRACT FROM AUTHOR]

In this study, electrochemical (EC G-G : graphite anode and cathode, EC I-G : iron anode and graphite cathode) enhanced heterogeneous activation of peroxymonosulfate (PMS) by CoFe 2 O 4 nanoparticles for the degradation of norfloxacin (NOR) in water was investigated. Although a higher NOR removal efficiency was achieved in EC I-G /CoFe 2 O 4 /PMS system, the generation of Fe3+ had resulted in the deposition of iron mud and affect the recovery of CoFe 2 O 4. Under the optimum reaction conditions of CoFe 2 O 4 /PMS system, the final removal efficiency of NOR did not show significant difference in EC G-G /CoFe 2 O 4 /PMS system (96.0%) and CoFe 2 O 4 /PMS system (95.5%), but the value of apparent rate constant significantly increased in EC G-G /CoFe 2 O 4 /PMS system (0.21 min−1) compared with CoFe 2 O 4 /PMS system (0.11 min−1). Similar NOR degradation pathways were obtained in these two systems, and the TOC removal efficiency in EC G-G /CoFe 2 O 4 /PMS system (28.8%) is almost as low as CoFe 2 O 4 /PMS system (26.0%). Therefore, it can be proposed that the applied electric field through active electrodes can accelerate the reaction of heterogeneous catalytic oxidation, but does not participate much in NOR degradation. However, the TOC removal efficiency (30 min) could be reached 68.7% as the mass ratio of PMS to CoFe 2 O 4 increased to 5:1 (250 mg L−1: 50 mg L−1). The EC G-G /CoFe 2 O 4 /PMS system is a promising low-cost technique for efficient mineralization of antibiotics in wastewater. [Display omitted] • Electro-enhanced heterogeneous catalysis is studied with common graphite electrode. • Electric field can accelerate the reaction of heterogeneous catalytic oxidation. • Meaningless consumption of PMS can be avoided and generate more free radicals. • Efficient mineralization of NOR is achieved with high PMS/CoFe 2 O 4 mass ratio. • The structure of CoFe 2 O 4 nanoparticles almost unchanged after the reaction. [ABSTRACT FROM AUTHOR]

Eutrophication pollution seriously threatens the sustainable development of Lake Taihu, China. In order to identify the primary parameters of water quality and the potential pollution sources, the water quality dataset of Lake Taihu (2010–2014) was analyzed with the water quality index (WQI) and multivariate statistical analysis methods. Principle component analysis/factor analysis (PCA/FA) and correlation analysis screened out five significant water quality indicators, i.e. potassium permanganate index (COD Mn), total nitrogen (TN), total phosphorus (TP), chloride ion (Cl−) and dissolved oxygen (DO), to represent the whole datasets and evaluate the water quality with WQI. Since northwestern of Lake Taihu was the most heavily polluted area, the parameters of the water quality were analyzed to further explore the potential sources and their contributions. Five potential pollution sources of northwestern lake were identified, and the contribution rate of each pollution source was calculated by the absolute principal component score-multiple linear regression (APCS-MLR) and positive matrix factorization (PMF) models. In brief, the PMF model was more suitable for pollution source apportionment of the northwestern lake, and the contribution rate was ranked as agricultural non-point source pollution (26.6%) > domestic sewage discharge (23.5%) > industrial wastewater discharge and atmospheric deposition (20.6%) > phytoplankton growth (16.0%) > rainfall or wind disturbance (13.4%). This study might provide useful information for the optimization of water quality management and pollution control strategies of Lake Taihu. Image 1 • PCA/FA and correlation analysis screened out primary water quality parameters. • WQI and CA identified spatiotemporal distribution characteristics of water quality. • PCA/FA identified potential pollution sources in the heavily polluted area. • The APCS-MLR and PMF figured out contributions of pollution sources in distinct areas. [ABSTRACT FROM AUTHOR]