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Current algal-bacterial consortia require high hydraulic retention times (HRTs, 2–10 days) to efficiently remove pollutants from domestic wastewaters. A novel algal-bacterial biofilm reactor was developed for a much lower HRT. The results showed that an HRT of 12 h ensured 90% removal of organic matter and ammonium, and phosphate removal was approximately 30%. Decreasing the HRT to 8 h significantly deteriorated the reactor's pollutant removal efficiencies and increasing the HRT to 24 h did not improve these efficiencies. Illumination, which was light source for algae, was provided by a LED light. Activity tests showed that organic matter and ammonium removal rates resulting from illumination were 70% and 50%, respectively, of the rates when dissolved oxygen concentration was maintained at 2 mg/L. Chemical oxygen demand (COD) removal rates resulted from illumination and aeration were 18.63 and 25.38 mg COD/L.h, respectively. The phosphate removal rate was 0.26 and 0.43 mg/L.h when illumination and aeration were applied, respectively. The ammonium removal rates were approximately 10,390 and 5000 mg NH 4 + − N / m 2. d when the reactor was aerated or illuminated, respectively. These two rates were significantly higher than reported nitrification rates. Moreover, the percentage of Oscillatoria sp. increased from below 10% to over 90% under the applied organic load and temperature, while the percentage of fast growing algae, Chlorella, chroococcus sp and Scenedesmus sp., decreased from over 90% to below 10%. These results showed that an algal-bacterial biofilm reactor with a low reactor footprint was developed. [ABSTRACT FROM AUTHOR]

• Iron embedded high porous acicular mullite was synthesized to remove Cd(Ⅱ) from water. • Acicular mullite can load more iron than commercial ceramsite. • Iron embedment enhances the adsorption of Cd(Ⅱ) by ceramic granules. • Adsorption amount of Cd(Ⅱ) positive relationship with the solution pH value. • Site energy distribution of iron-embedded acicular mullite for Cd(Ⅱ) adsorption was calculated. Iron-embedded granular acicular mullite was synthesized and used to remove Cd(II) from water. Characterization of iron-embedded acicular mullite and its adsorption behavior for Cd(II) were studied with the commercial ceramsite as a comparison. Iron oxyhydroxide is successfully embedded into acicular mullite, but mainly hematite loaded on its counterpart. After iron embedment, the specific surface area, iron content and pore volume of acicular mullite vastly increase. The adsorption isothermal fits well by the Langmuir-Freundlich model. Based on the model, the maximum adsorption capacity (Q g) for Cd(II) on iron-embedded mullite is 2.808 mg/g, which is 8 times higher than the virgin acicular mullite and 3 times higher than the commercial ceramsite. Moreover, site energy distribution for Cd(II) adsorbed on iron-embedded mullite and commercial ceramsite were calculated to explore the adsorption mechanisms. The average site energy (µ(E *)) of Cd(II) adsorption on all samples is similar but the energy distribution frequency function F (E m *) for Cd(II) adsorption on iron-embedded acicular mullite was 8 times higher than its counterpart. Consequently, this iron-embedded acicular mullite is efficient for the removal of Cd(II) in water and could be applied as advanced filter media on large scale. [ABSTRACT FROM AUTHOR]

Raman mapping spectra of Microcystis flosaquae (M. flosaquae) subjected to environmental perturbations were used to study the correlations among the characteristics of M. flosaquae by two‐dimensional (2‐D) Raman correlation spectroscopy. Overlapping Raman characteristics of the carotenoids in M. flosaquae and their differences in algal growths were shown in the 2‐D synchronous and asynchronous correlation spectra. The asynchronous correlation Raman spectra demonstrated the accumulation of carotenoids in M. flosaquae under normal culture condition and environmental perturbations. High light flux obviously led to the accumulation of β‐carotene in M. flosaquae in comparison with normal culture condition. The results showed that 2‐D Raman correlation spectroscopy can be used to analyze the correlation of complex changes of the Raman characteristics of M. flosaquae induced by different environmental conditions to assess the accumulation of the carotenoids in algae and to predict the algal growth phases. [ABSTRACT FROM AUTHOR]

Reservoirs are essential for the wellbeing of human societies, but can also be subject to negative ecological impacts. The Three Gorges Reservoir (TGR) in the upper Yangtze River is remarkable for its size and engineering; however, its effects on water quality are poorly understood. To the best of our knowledge, this study is the first to describe long-term (1992–2016) monitoring. It showed that the chemical oxygen demand (COD, via the potassium permanganate index) and total phosphorus (TP) have decreased 40.9% ± 9.9% and 22.2% ± 9.7% respectively in the TGR mainstream between impoundment in June 2003 and 2016, while total nitrogen (TN) and ammonium (NH 4 -N) have increased 1.3% ± 2.4% and 8.2% ± 2.6%. In addition, phytoplankton biomass has increased by a factor of 2.7 (1.1–4.8) over pre-impoundment levels in the mainstream, and tributary algal blooms have increased in frequency since 2004. The reductions in COD and TP were caused primarily by decreases in water flow speed, which lead to sediment settlement. The anti-seasonal operation pattern and water volume increased TGR may also increases the dilution capacity. TN and ammonium are less affected by sediment deposition and have increased slightly under intensified human activities. Decreased water flow speeds and nutrient enrichment have promoted increases in algal biomass, leading to blooms in tributary backwater zones. In situ experiments indicate that phytoplankton growth in the TGR is phosphorus limited during all seasons. Therefore, controlling phosphorus will reduce the short-term eutrophication potential in the reservoir. However, concurrent control of nitrogen and phosphorus inputs are necessary in the long term. [ABSTRACT FROM AUTHOR]

Highlights • SMX sorbed through multiple interactions revealed strong affinity with sludge. • Partition function dominated the sorption behavior of CBZ, BPA and EE2 onto sludge. • Sorption process of SMX was mainly observed in anaerobic stage of SBR. • Biodegradation of SMX primarily occurred in aerobic stage of SBR. Abstract The occurrence of trace organic contaminants (TOrCs) at detectable levels in wastewater and surface waters led to a growing concern over the persistence of toxicological effects in the environment. Sorption is significant process in municipal wastewater treatment plants to remove TOrCs due to low water solubility and high hydrophobic of most TOrCs. The work herein explored the sorption behavior of four typical TOrCs onto sludge solids. The sorption process was spontaneous and exothermic. Greater sorption amount was observed for EE2 that 60.9% of EE2 in liquid phase was removed, followed by BPA (49.4%) and SMX (35.8%), while only 19.5% of CBZ was adsorbed. Sorption of CBZ, BPA and EE2 was primarily a physical process dominated by partition function, while SMX was mainly sorbed through multiple interactions, and this strong affinity between SMX and activated sludge resulted in least desorption rate. Deep insight into the pathway of SMX in SBR revealed that total removal rate in a period was about 50.22%. Sorption process was observed in anaerobic stage, and biological degradation was mainly occurred in aerobic stage with biodegradation rate of 29.18%. [ABSTRACT FROM AUTHOR]

Abstract Nitrite is one of the world's major contaminants in drinking water resources, and granular anthracite is often used as filter medium in water treatment. In this study, the adsorption characteristics of nitrite on granular anthracite under various temperatures were investigated through adsorption kinetic, isotherm models, and site energy distribution theory. The adsorption of nitrite on granular anthracite was an endothermic reaction, while intraparticle diffusion was not the only rate control step. The adsorption could be well described by using pseudo-second-order and Langmuir–Freundlich equations. The adsorption capacity was 402.51 mg NO 2 −-N kg−1 at 298 K, which could be significantly improved to 1380.1 mg NO 2 −-N kg−1 when the temperature reached 308 K. Furthermore, nitrite ions first occupied the high-energy adsorption sites and then diffused to the low-energy adsorption sites on granular anthracite. There were more sites, including high-energy sites and low-energy sites, for nitrite adsorption at 308 K. Besides, the thickness of the boundary layer increased with the adsorption capacity improved at a higher temperature, and nitrite ions were adsorbed mainly through chemical mechanisms. Moreover, the neutral pH was helpful for the adsorption. The presence of co-existing ions could limit the adsorption and the effect followed the order of PO 4 3− > CO 3 2− > SO 4 2− > NO 3 − > Cl−. The saturated anthracite could be effectively regenerated by 0.2 mol L−1 HCl solution. Therefore, the granular anthracite used as filter medium also has a possible application as a nitrite scavenger at the same time. Graphical abstract fx1 Highlights • The adsorption characteristics of nitrite on granular anthracite were investigated. • Site energy distribution can exactly explain the adsorption at various temperatures. • Nitrite ions first occupied high-energy sites and then spread to low-energy sites. • Nitrite ions were adsorbed mainly through chemical mechanisms. [ABSTRACT FROM AUTHOR]

Long-term structural stability of aerobic granular sludge (AGS) is a major challenge in AGS biotechnology. This work investigated variations in the sludge performance, structural stability, and intrinsic mechanisms of AGS under three feeding strategies (R1 direct aeration after fast feeding, R2 anaerobic stirring after fast feeding and R3 anaerobic plug-flow slow feeding). The AGS sequencing batch reactor used in this study was in stable operation with biomass of 6–10 gMLSS/L and a hydraulic retention time of 4 h. The results showed that the best sludge performance was demonstrated in R3, followed by R2 and R1. These differences were caused by extracellular polymeric substances (EPS) and microbial communities. The excellent sludge performance in R3 was attributed to the high hydrophobicity in the EPS as well as the gel properties due to the high hydrogen bonding content in the exopolysaccharide (PS). Similarly, the gel properties formed by the high hydrogen bonding content maintain the sludge stability in R1. Slow-growing dominant bacteria were enriched in the AGS of R2 and R3 with alternating anaerobic/aerobic operation modes, resulting in outstanding sludge performance. In contrast, high abundance of the filamentous bacteria Neomegalonema was enriched in the AGS of R1 without an anaerobic phase, resulting in relatively poor sludge stability. Variations in EPS characteristics and microbial community under the different feeding strategies were the main mechanisms responsible for the long-term operation of AGS. This study could provide a theoretical foundation and technical assistance for the sustainable operation of AGS reactors. [Display omitted] • AGS performance was affected by the different feeding strategies. • Excellent AGS performance was achieved under anaerobic plug-flow slow feeding. • The gel properties of exopolysaccharides favor stability of granule sludge. • Differences in the AGS stability were due to the microbial community structure. [ABSTRACT FROM AUTHOR]

The self-assembly of a mixture of hexadecanoic acid with (R)-2-Br-hexadecanois acid and (S)-2-Br-hexadecanois acid at the liquid-solid interface is investigated using scanning tunneling microscopy (STM). The absolute conformation of the bromine atom in 2-Br-hexadecanoic acids is determined to be pointing up away from the graphite surface.

High-saline wastewater treatment processes have a high energy demand, while microalgae-driven wastewater biotechnology is both economical and environmentally friendly, and the use of microalgae to treat high-saline wastewater can effectively reduce energy consumption. However, it is unclear whether the performance of microalgae reactor can be stable for a long time. In this study, an open continuous-flow biofilm photobioreactor using Dunaliella salina was innovatively constructed, and operated in combination with a membrane bioreactor (MBR) for high-saline wastewater treatment. The purpose of this study was to investigate the long-term performance of MBR, MBPBR alone and their combined operation for the removal of organic matter, phosphorus and nitrogen, explore the pathway and mechanism of nitrogen and phosphorus removal by MBPBR, and evaluate the feasibility of MBPBR-MBR integrated system for the treatment of saline wastewater. The MBR effectively removed most of the organic matter and converted ammonia nitrogen into nitrate nitrogen, which is a preferred nitrogen source for the growth of Dunaliella salina , thereby providing favorable water quality for Dunaliella salina in the subsequent MBPBR. The MBPBR, with a hydraulic retention time (HRT) of 72 h, achieved a NO 3 --N removal load of 74.9 g N/(m3∙d) and a removal efficiency of approximately 60 %, and the PO 4 3--P removal load of 8.33 g P/(m3∙d) and removal efficiency of over 80 %. The MBR-MBPBR system demonstrated long-term stability, achieving removal efficiencies of 84.3 %, 81.6 %, and 91.0 % for COD, TN and PO 4 3--P, respectively. Within the MBPBR, the growth of algae and their assimilation contributed 44.9 % and 38.7 % of the nitrogen and phosphorus removal, respectively. The abundance of Dunaliella salina in the MBPBR remained at approximately 90 % for over 40 days of operation, providing an opportunity for Dunaliella salina recovery. These findings provide valuable insights into the utilization of microalgae for the treatment of high-salinity wastewater, while also supporting the practical implementation of microalgae-based treatment methods for such wastewater. [Display omitted] • A combined system based on Dunaliella salina for high-saline wastewater treatment. • Highly efficient pollutant removal in combined system. • 90 % high abundance of Dunaliella salina in microalgae biofilm photobioreactor. • Low-energy treatment of saline wastewater achieved through MBR-MBPBR. [ABSTRACT FROM AUTHOR]

Abstract 17α-Ethinylestradiol (EE2) and bisphenol A (BPA) are highly toxic and widely detected endocrine-disrupting compounds (EDCs) throughout the world in surface waters. Adsorption is an effective way to remove EE2 and BPA from water. However, it is difficult to clearly explain the mechanism of adsorption theoretically only through classic adsorption models. In order to insight into the adsorption of EE2 and BPA, site energy distribution (SED) theory was introduced to investigate the adsorption of EE2 and BPA on heterogeneous surfaces. EE2 and BPA were adsorbed on un-anthracite (unmodified anthracite) and 4K anthracite (4 mol L−1 KOH-modified anthracite) in single- and bi-component systems under various temperatures and pHs. The results suggested that EE2 and BPA molecules first occupied the high-energy adsorption sites and then spread to low-energy adsorption sites. There were more high-energy sites on 4K anthracite, resulting in a higher adsorption capability for EE2 and BPA. Besides, increasing temperature and acidic environment were conducive to the EE2 and BPA adsorption. SED analyses indicated that, in neutral solutions, π-π electron donor-acceptor (EDA) interaction might be the primary mechanism for BPA adsorption, while ligand exchange, hydrogen bonds, and π-π EDA interaction might simultaneously work in the adsorption of EE2. It was possible that EE2 molecule was near perpendicular to surface, while BPA molecule was parallel to surface, resulting in the higher adsorption capacities of EE2. However, compared with EE2, BPA had outstanding competitive advantages in bi-component system because of the stronger π-π EDA interaction between BPA and anthracite. Graphical abstract Image 1 Highlights • Novel insight into the adsorption of EE2 and BPA on anthracite surface was given. • Site energy distribution was used to investigate the adsorption of EE2 and BPA. • More high-energy sites on 4K anthracite resulted in a higher adsorption capability. • BPA had competitive advantages in high-energy area in bi-component system. [ABSTRACT FROM AUTHOR]

Background: Nanosecond pulsed electric fields (nsPEFs) can produce more significant biological effects than traditional electric fields and have thus attracted rising attention in developing medical applications based on short pulse duration and high field strength, such as effective cancer therapy. However, little is known about their effects on the differentiation of stem cells. Furthermore, mechanisms of electric fields on chondrogenic differentiation of mesenchymal stem cells (MSCs) remain elusive, and effects of electric fields on cartilage regeneration need to be verified in vivo. Here, we aimed to study the effects of nsPEFs on chondrogenic differentiation of MSCs in vitro and in vivo and further to explore the mechanisms behind the phenomenon. Methods: The effects of nsPEF-preconditioning on chondrogenic differentiation of mesenchymal stem cells (MSCs) in vitro were evaluated using cell viability, gene expression, glycosaminoglycan (sGAG) content, and histological staining, as well as in vivo cartilage regeneration in osteochondral defects of rats. Signaling pathways were investigated with protein expression and gene expression, respectively. Results: nsPEF-preconditioning with proper parameters (10 ns at 20 kV/cm, 100 ns at 10 kV/cm) significantly potentiated chondrogenic differentiation capacity of MSCs with upregulated cartilaginous gene expression and increased matrix deposition through activation of C-Jun NH2-terminal kinase (JNK) and cAMP-response element binding protein (CREB), followed by activation of downstream signal transducer and activator of transcription (STAT3). Implantation of nsPEF-preconditioned MSCs significantly enhanced cartilage regeneration in vivo, compared with implantation of non-nsPEF-preconditioned MSCs. Conclusion: This study demonstrates a unique approach of nsPEF treatment to potentiate the chondrogenic ability of MSCs through activation of JNK/CREB-STAT3 that could have translational potential for MSC-based cartilage regeneration. [ABSTRACT FROM AUTHOR]

Nano-pulse stimulation (NPS) is a novel technology to induce cancer apoptosis. In this study, based on the energy-dose effect of NPS, we designed a special NPS sequence (NPSS) with low field intensity. The effectiveness and mechanisms of NPSS on oral cancer therapy were evaluated by cell proliferation assays, microscopic investigation, JC-1 mitochondrial membrane potential assay, tumor inhibition assays, immunohistochemistry (IHC) assay, Ca 2+ , NOS and ROS detection assays, respectively. The results demonstrated that NPSS treatment significantly inhibited oral cancer growth in vitro and in vivo . Furthermore, we found that NPSS treatment induced an obviously apoptosis and mitochondrial membrane potential (ΔΨm) reduction in Cal-27 cells. Notably, further experiments revealed that the mechanisms of crosstalk signaling between NO, ROS and Ca 2+ involvement in NPSS treatment. In conclusion, this is a proof-of-concept study that provides a potential alternative strategy for developing and applying NPSS in oral cancer therapy. [ABSTRACT FROM AUTHOR]

This study investigated phytoplankton and bacterioplankton communities by flow cytometer in a tributary backwater area of the Three Gorges Reservoir, China. Samplings were conducted in two cyanobacterial bloom periods (May and August) and no algal-blooms period (November) of 2014, representing three different operational stages of the reservoir, i.e., reservoir discharge period, fluctuating period in the summer flood season, and high water level in the impoundment period. Phyto- and bacterioplankton exhibit a wide range of variability along the depth profiles of the water column. In the investigated two cyanobacterial bloom periods, prokaryotes accounted for over 50% of the total phytoplankton. As for bacterioplankton, low nucleic acid bacteria were dominant in August and November. A positive correlation was observed between phytoplankton (pico- and nanophytoplankton), Chl a, and bacterioplankton. High nucleic acid groups and prokaryotes were highly coupled in May and August, which indicated that this high nucleic acid group could probably contribute to the explanation of cyanobacterial bloom formation in this area. [ABSTRACT FROM AUTHOR]

Anthracite is a natural inorganic-organic hybrid environmentally friendly material, which often is used as a filter medium in water treatment. In this study, we processed anthracite particles using potassium hydroxide (KOH) with different concentrations. The anthracites, before and after treatments, were characterized by Brunauer-Emmett-Teller analysis, scanning electron microscopy, Fourier transform infrared spectrometer, X-ray diffraction, X-ray photoelectron spectroscopy, and Boehm titration. The specific surface area and the amount of total alkalinity of anthracite were 23.73 m2 g−1 and 0.38 mmol g−1 (increased by 101 and 217%, respectively) for 4 M KOH treatments, but decreased to 10.09 m2 g−1 and 0.12 mmol g−1 for 10 M KOH treatments. We selected 4 M KOH-modified anthracite particles to remove 17α-ethinylestradiol (EE2) and bisphenol A (BPA) from water with unmodified anthracite used in control experiments. The pseudo-second-order model fitted well for the whole adsorption process, and intraparticle diffusion was not the unique rate-controlling step. The equilibrium adsorption data fitted well with the Langmuir-Freundlich model, and the adsorption capacities of EE2 and BPA on anthracite particles after 4 M KOH treatments were 0.7914 and 0.4327 mg g−1 (increased by 138 and 97%, respectively), because the active sites markedly increased. The ligand exchange, hydrogen bonds, and π-π electron donor-acceptor interactions were the main adsorption mechanisms. The 4 M KOH-modified anthracite could be promising in large-scale applications, both as filter medium and adsorbent for organic contaminants. [ABSTRACT FROM AUTHOR]

Cyanobacteria exhibit a variety of adaptive strategies that allow them to thrive in ever-changing aquatic environments. Here, successive steady states of continuous cultures were used to investigate the effects of quantified turbulence on the biochemical compounds and physiological processes of Anabaena flos-aquae in a photobioreactor under different dilution rates. A rapid increase in cell density was clearly observed following an increase in the turbulent dissipation rate at all growth rates of A. flos-aquae. The photosynthetic response to irradiance curves showed that the turbulence-treated strains exhibited lower photosynthetic oxygen evolution and saturating irradiance as well as higher respiration in rapidly growing young cells, indicating that they might not be very adaptable to high turbulent dissipation rates. Additionally, there was an increase in the protein levels of A. flos-aquae with increasing turbulence at all growth rates, whereas carbohydrate formation and lipid accumulation demonstrated the opposite trends. At a high growth rate, the level of carbohydrates decreased whereas that of lipids increased, which was interpreted as reflecting an adaptation to the turbulent environment. These findings suggest that turbulence sensitivity is shear regimen- and growth rate-dependent in A. flos-aquae. The high respiration capacity, low saturating irradiance, and conversion of carbohydrates to lipids represent effective measures for revealing the adaptive strategies of rapidly growing young cells under hydrodynamic regimes. The results regarding optimum lipid accumulation with specific growth traits have important implications for the design of cultivation methods of cyanobacteria resource utilization with respect to regulating turbulence. [ABSTRACT FROM AUTHOR]