Challenges and advancements in membrane distillation crystallization for industrial applications.

Membrane distillation crystallization (MDC) is an emerging hybrid thermal membrane technology that synergizes membrane distillation (MD) and crystallization, which can achieve both freshwater and minerals recovery from high concentrated solutions. Due to the outstanding hydrophobic nature of the membranes, MDC has been widely used in numerous fields such as seawater desalination, valuable minerals recovery, industrial wastewater treatment and pharmaceutical applications, where the separation of dissolved solids is required. Despite the fact that MDC has shown great promise in producing both high-purity crystals and freshwater, most studies on MDC remain limited to laboratory scale, and industrializing MDC processes is currently impractical. This paper summarizes the current state of MDC research, focusing on the mechanisms of MDC, the controls for membrane distillation (MD), and the controls for crystallization. Additionally, this paper categorizes the obstacles hindering the industrialization of MDC into various aspects, including energy consumption, membrane wetting, flux reduction, crystal yield and purity, and crystallizer design. Furthermore, this study also indicates the direction for future development of the industrialization of MDC.

Transcriptome Analyses Reveal the Role of Light in Releasing the Morphological Dormancy of Celery Seed by Integrating Plant Hormones, Sugar Metabolism and Endosperm Weakening.

Celery seed is known to be difficult to germinate due to its morphological dormancy. Light is the key signal to release morphological dormancy and promote seed germination. However, this mechanism has rarely been studied. We performed physiological, transcriptome analyses on celery seed exposed to light and dark to decipher the mechanism by which light promotes germination of celery seed. The results showed that light significantly enhanced the expression of gibberellin synthesis genes and abscisic acid degradation genes and inhibited the expression of abscisic acid synthesis genes and gibberellin degradation genes. Moreover, gibberellin synthesis inhibitor could completely inhibit the germination capacity of celery seed, indicating that gibberellin is indispensable in the process of celery seed germination. Compared with dark, light also increased the activity of α-amylase and ß-amylase and the expression of related coding genes and promoted the degradation of starch and the increase of soluble sugar content, suggesting that light enhanced the sugar metabolism of celery seed. In addition, transcriptome analysis revealed that many genes related to endosperm weakening (cell wall remodeling enzymes, extension proteins) were up-regulated under light. It was also found that light promoted the accumulation of hydrogen peroxide in the radicle, which promoted the endosperm weakening process of celery seed. Our results thus indicated that light signal may promote the release of morphological dormancy through the simultaneous action of multiple factors.

Application of enhanced membrane bioreactor (eMBR) for the reuse of carwash wastewater.

Minimising the usage of potable water in industrial and cleaning processes is essential to conserve fresh water. Recycling treated wastewater will help to do so. However, high quality treated wastewater is required for reuse and recycling. This study evaluated the performance of an enhanced membrane bioreactor (eMBR) in treating car wash wastewater for the purpose of reuse. The eMBR consisted of an anaerobic tank, an anoxic tank, an aerobic membrane bioreactor (AMBR) and a UV disinfection unit. The effects of hydraulic retention time of the eMBR on the treated water quality parameters and operating parameters were evaluated. The eMBR produced high quality recyclable water (0.5-10.2 mg/L of COD, 0.18-0.83 NTU of turbidity, 0 org. of E. Coli/100 mL) meeting Class A recycle water standards. Decrease in the mixed liquor suspended solids concentration in the AMBR (from 294 to 117 mg/L) reduced the fouling of the membrane which increased the permeate flux (from 5.9 to 6.7 L/m2h). This is unique to the eMBR system used in this study. However, when the flux exceeded the critical flux, the trans-membrane pressure increased significantly.

Impact of green algae on the measurement of Microcystis aeruginosa populations in lagoon-treated wastewater with an algae online analyser.

Tests on the algae online analyser (AOA) showed that there was a strong direct linear correlation between cell density and in vivo Chl-a concentration for M. aeruginosa over the range of interest for a biologically treated effluent at a wastewater treatment plant (25,000-65,000 cells mL(-1), equivalent to a biovolume of 2-6 mm3 L(-1)). However, the AOA can provide an overestimate or underestimate of M. aeruginosa populations when green algae are present in the effluent, depending on their species and relative numbers. The results from this study demonstrated that the green algae (e.g., Euglena gracilis, Chlorella sp.) in the field phytoplankton population should be considered during calibration. In summary, the AOA has potential for use as an alert system for the presence of M. aeruginosa, and thus potentially of cyanobacterial blooms, in wastewater stabilization ponds.

A comparative study of programs to predict direct photolysis rates in wastewater systems.

A wide range of contaminants of emerging concern (CECs) are known to photodegrade in the surface layers of natural waters and wastewater systems. Computer programs such as GCSolar, ABIWAS, APEX, EXAMS and WASP model the direct photolysis rates and half-lives of CECs, usually as a function of the solar irradiance, water molar light extinction, chemical molar light absorption and reaction quantum yield. These programs have been used extensively for studies in natural water systems in the northern hemisphere. However, their applicability to wastewater treatment systems such as waste stabilisation ponds and/or southern hemisphere conditions is not well studied. Here we present a comparative review of the major software used and their potential applicability to predicting direct photolysis rates and half-lives in wastewater. The newer equivalent monochromatic wavelength, approach, which enables the approximation of polychromatic photodegradation via a monochromatic wavelength is also discussed. Current software appears to be less suitable for modelling photodegradation in wastewater systems in the southern hemisphere than the northern hemisphere as their internal databases are based on data from natural waters in the northern hemisphere. This may be because there have been few attempts to model CEC photolysis in wastewater systems, particularly in the southern hemisphere. This indicates that either new software needs to be developed, or these programs need to be updated with data on wastewater matrices and/or the southern hemisphere. We anticipate this review will promote the adaptation of these programs as tools to further the understanding CEC photodegradation in wastewater treatment plants.

Unveiling the existence and ecological hazards of trace organic pollutants in wastewater treatment plant effluents across China.

The presence of trace organic pollutants in the effluent of wastewater treatment plants (WWTPs) poses considerable risks to aquatic organisms and human health. A large-scale survey of 302 trace organic pollutants in the effluent of 46 Chinese WWTPs was conducted to gain an improved understanding of their occurrence and ecological risks. The survey data showed that 216 compounds in 11 chemical classes had been detected in effluents. The sum concentrations of the trace contaminants in effluent ranged from 1,392 ng/L to 35,453 ng/L, with the maximum concentration of perfluoroalkyl substances (PFASs) recorded as the highest (30,573 ng/L), which was markedly less than the reported 185,000 ng/L for the 38 American WWTPs. The concentration of bisphenol analogs (BPs) was up to 4,422 ng/L, significantly higher than those reported in France, Germany, Japan, Korea, and the U.S. PFASs and BPs were the major pollutants, accounting for 59% of the total pollution. Additionally, a total of 119 contaminants were found to have ecological risks (RQ > 0.01). Among these, 23 contaminants (RQ > 1.0) warrant higher attention and should be prioritized for removal. This study lists valuable information for controlling contaminants with higher priority in WWTP effluent in China.

Assessing the potential of a UV-based AOP for treating high-salinity municipal wastewater reverse osmosis concentrate.

The UVC/H(2)O(2) process was studied at laboratory scale for the treatment of one moderate (conductivity ∼8 mS/cm) and two high salinity (∼23 mS/cm) municipal wastewater reverse osmosis concentrate (ROC) samples with varying organic and inorganic characteristics. The process efficiency was characterized in terms of reduction of dissolved organic carbon (DOC), chemical oxygen demand (COD), colour and absorbance at 254 nm (A(254)), and the improvement of biodegradability. The reduction of colour and A(254) was significantly greater than for DOC and COD for all samples due to the greater breakdown of humic compounds, as confirmed by fluorescence excitation-emission matrix spectra. Fairly small differences in the reduction of DOC (26-38%) and COD (25-37%) were observed for all samples, suggesting that the salinity of the ROC did not have a significant impact on the UVC/H(2)O(2) treatment under the test conditions. The biodegradability of the treated ROC samples improved markedly (approximately 2-fold) after 60 min UVC/H(2)O(2) treatment. This study indicates the potential of UVC/H(2)O(2) treatment followed by biological processes for treating high-salinity concentrate, and the robustness of the process where the characteristics of the secondary effluent (influent to RO) and thus resultant ROC vary significantly.

Using fluorescence index (FI) of dissolved organic matter (DOM) to identify non-point source pollution: The difference in FI between soil extracts and wastewater reveals the principle.

Traceability and quantification of agricultural non-point source pollution are of great significance to water pollution management in watersheds. In this study, fluorescence components and indices of dissolved organic matter (DOM) in the river, wastewater and soil extracts from different land use types were analyzed to screen indicators that can identify non-point source pollution in 15 independent small watersheds located at the southern Qinling piedmont (China). The results showed that DOM fluorescence components in soil extracts among different land uses didn't have significant differences. The values of humification index (HIX) did not vary obviously between soil extracts and wastewater, with the mean values ranging from 3.4 to 3.9. However, the average value of fluorescence index (FI) of effluent wastewater was about 2.1 and did not change significantly through treatment. The FI values of soil extracts were generally between 1.5 and 1.7. The FI values in most river waters were just between the FI values of wastewater and soil extracts. This phenomenon indicated that FI could be used as an indicator to distinguish point source and non-point source pollution. Besides, the correlation analysis showed a significant positive relationship between the non-point source pollution calculated by FI and δ15N. The relationship was different in January and July, but further confirmed the reliability of using FI to quantify non-point source pollution. This study demonstrated the feasibility of using FI to identify non-point source pollution. When combined with handheld fluorescence spectrometers and unmanned aerial vehicle-mounted fluorescence spectrometers, this method may be adopted more widely.

Efficiency of lagoon-based municipal wastewater treatment in removing microplastics.

Municipal wastewater treatment plants act as a sink, but also are a source of microplastics in the environment. A conventional wastewater lagoon system and an activated sludge (AS)-lagoon system in Victoria (Australia) were investigated through a two-year sampling program to understand the fate and transport of MP in such treatment processes. The abundance (>25 µm) and characteristics (size, shape, and colour) of the microplastics present in the various wastewater streams were determined. The mean values of MP in the influent of the two plants were 55.3 ± 38.4 and 42.5 ± 20.1 MP/L, respectively. The dominant MP size of influent and final effluent was <500 µm, with 25-200 µm accounting for >65 % of the total MP; synthetic fibres were the dominant MP in all wastewater streams. Influent MP concentration was significantly higher in summer than in other seasons for both systems, which was related to the lower plant inflow due to less stormwater entering the sewer during summer. The promising MP removal capability of the lagoon system (97 %) was attributed to its lengthy wastewater detention time (total HRT >250 days, including the storage lagoons) that would allow effective separation of MP from the water column via various physical and biological pathways. For the AS-lagoon system, the high MP reduction efficiency (98.4 %) was attributed to the post-secondary treatment of the wastewater with the lagoon system, in which MP was further removed during the month-long detention in the lagoons. The results indicated the potential of such low-energy and low-cost wastewater treatment systems for MP control.

A new ultra-wide-field fundus dataset to diabetic retinopathy grading using hybrid preprocessing methods.

Diabetic retinopathy(DR) is a common early diabetic complication and one of the main causes of blindness. In clinical diagnosis and treatment, regular screening with fundus imaging is an effective way to prevent the development of DR. However, the regular fundus images used in most DR screening work have a small imaging range, narrow field of vision, and can not contain more complete lesion information, which leads to less ideal automatic DR grading results. In order to improve the accuracy of DR grading, we establish a dataset containing 101 ultra-wide-field(UWF) DR fundus images and propose a deep learning(DL) automatic classification method based on a new preprocessing method. The emerging UWF fundus images have the advantages of a large imaging range and wide field of vision and contain more information about the lesions. In data preprocessing, we design a data denoising method for UWF images and use data enhancement methods to improve their contrast and brightness to improve the classification effect. In order to verify the efficiency of our dataset and the effectiveness of our preprocessing method, we design a series of experiments including a variety of DL classification models. The experimental results show that we can achieve high classification accuracy by using only the backbone model. The most basic ResNet50 model reaches an average of classification accuracy(ACA) 0.66, Macro F1 0.6559, and Kappa 0.58. The best-performing Swin-S model reaches ACA 0.72, Macro F1 0.7018, and Kappa 0.65. DR grading using UWF images can achieve higher accuracy and efficiency, which has practical significance and value in clinical applications.

Investigating the fate and transport of microplastics in a lagoon wastewater treatment system using a multimedia model approach.

Effluents of municipal wastewater treatment plants (WWTPs) are a major source of microplastics (MP) in the terrestrial and aquatic environment; there is growing concern over the environmental and health impacts of MP pollution. In this study, the MP removal (MP cut-off size= 25 µm) in a lagoon-based wastewater treatment system was predicted by developing a model based on the multimedia modelling approach and utilising MP-specific properties for improving the understanding of the fate and transport of MP in such treatment processes. The high MP removal efficiency of the lagoon treatment system as predicted by the model (99.3%) and determined with the site wastewater samples (97%) could be attributed to its high HRT (>200 days, including that for the storage lagoons) that would allow effective MP removal with the system. Evaluation of the model predictions of MP concentration demonstrated reasonable alignment with measured concentrations in the facultative, maturation and winter storage lagoons of the system. Further evaluation of model predictions for various MP size classes (25-100, 100-200, 200-500 and >500 µm) obtained reasonable predictions for MP within the size range of 25-500 µm, indicating that the model is better used for predicting MP within that size range. The sensitivity analysis revealed the model predictions to be sensitive towards the operating/water quality parameters in the order of influent wastewater flowrate, MP concentration in influent wastewater, and MP settling rate in the water column of the lagoon. The study showed the potential of the developed model as a quantitative assessment tool for better management of MP in lagoon-based WWTPs.

ASC/Caspase-1-activated endothelial cells pyroptosis is involved in vascular injury induced by arsenic combined with high-fat diet.

Environmental arsenic (As) or high-fat diet (HFD) exposure alone are risk factors for the development of cardiovascular disease (CVDs). However, the effects and mechanisms of co-exposure to As and HFD on the cardiovascular system remain unclear. The current study aimed to investigate the combined effects of As and HFD on vascular injury and shed some light on the underlying mechanisms. The results showed that co-exposure to As and HFD resulted in a significant increase in serum lipid levels and significant lipid accumulation in the aorta of rats compared with exposure to As or HFD alone. Meanwhile, the combined exposure altered blood pressure and disrupted the morphological structure of the abdominal aorta in rats. Furthermore, As combined with HFD exposure upregulated the expression of vascular endothelial cells pyroptosis-related proteins (ASC, Pro-caspase-1, Caspase-1, IL-18, IL-1ß), as well as the expression of vascular endothelial adhesion factors (VCAM-1 and ICAM-1). More importantly, we found that with increasing exposure time, vascular injury-related indicators were significantly higher in the combined exposure group compared with exposure to As or HFD alone, and the vascular injury was more severe in female rats compared with male rats. Taken together, these results suggested that the combination of As and HFD induced vascular endothelial cells pyroptosis through activation of the ASC/Caspase-1 pathway. Therefore, vascular endothelial cells pyroptosis may be a potential molecular mechanism for vascular injury induced by As combined with HFD exposure.

A complementary approach of response surface methodology and an artificial neural network for the optimization and prediction of low salinity reverse osmosis performance.

The treatment of saline water sources by reverse osmosis (RO) is being utilized increasingly to address water shortages around the world. The application of RO is energy-intensive; therefore, plant and process optimization are crucial. The desalination of low salinity water sources with total dissolved solids (TDS) of <5000 mg/L is less energy intensive than the desalination of highly saline seawater and brackish water. A gap exists in optimization studies on lower salinity water (TDS = 500-5000 mg/L). The novelty of the study is the development of a complementary approach using response surface methodology (RSM) and an artificial neural network (ANN) for performance modelling, optimization, and prediction of RO desalination of low salinity water. Feed water salinity, pressure, and temperature were controlled variables to model the performance of the RO system. A performance index incorporating salt rejection efficiency and permeate flux was used as the response target of the system. The optimal parameter combination within their modelled range for the best performance index occurred near the highest pressure input of 150.57 psi, at the temperature of 38.8 °C, and at the lowest feed salt concentration of 577 mg/L. Both the RSM and ANN models demonstrated high validity. The RSM and ANN showed R2 values of 0.99 each and with a root mean square error of 2.41 and 5.85 respectively. The RSM showed a small benefit in model accuracy over the ANN, but the ANN has the benefit of not requiring the central composite design before experimentation and being a continuously improving prediction method as more data becomes available. Further applications of the optimization and modelling approach can be applied to RO system optimization considering membrane types and additional feedwater characteristics.

Comprehensive Quality and Bioactive Constituent Analysis of Celery Juice Made from Different Cultivars.

Celery juice is rich in bioactive constituents, has good health properties, and is becoming much more popular, with its demand continuing to rise. The results of this study show that celery juice from Chinese cultivars contains more bioactive constituents, whereas celery cultivars from the United States and European countries have a higher juice yield. Compared with the other juices, the juices of five cultivars may taste sweeter, and the juices of three cultivars had a higher antioxidant capacity. The juices of six cultivars (three with the highest antioxidant capacity and three with the lowest antioxidant capacity) were selected to analyze bioactive constituents by LC/MS and GC/MS. A total of 71 phenolic acids, 38 flavonoids, 18 coumarins, 41 terpenoids, and 11 phthalides were detected in the juices of the six celery cultivars. The contents of 14 compounds had a more than 10-fold difference among these celery juices. This study first evaluated the comprehensive quality of the juices made from 26 celery cultivars and then analyzed the differences in bioactive constituents in the juices of6 celery cultivars. These findings provide information for the further study on the health functions of celery juice and can also guide celery juice production and celery breeding.

[Effect of schisandrin B on lung mRNA expression of transforming growth factor-beta1 signal transduction molecule in rat lungs exposed to silica].

OBJECTIVE: To investigate the effects of schisandrin B (Sch-B) on expression of transforming growth factor-beta1 (TGF-beta1) and signal transduction molecule mRNA in rat lungs exposed to SiO2, and explore the intervention mechanism of Sch-B on pulmonary fibrosis induced by SiO2. METHODS: Ninety six Wistar rats were randomly divided into control (normal saline) group, SiO2 group and SiO2 plus Sch-B group. The rats were exposed to SiO2 by direct tracheal instillation to establish the silicotic animal models. SiO2 group and SiO2 plus Sch-B group were treated with 1 ml SiO2 (50 mg/ml) for each rat From the first day after model establishment, SiO2 plus Sch-B group were orally given Sch-B (80 mg/kg) a day, control group and silica group were orally given olive oil. On the 3rd, 7th, 14th and 28th days after treatment, 8 rats in each group were sacrificed and samples were collected. The histo-pathological examination of lung was performed by HE staining. The expression levels of TGF-beta1, TGF-betaR II and Smad4 mRNA in the lung tissues were detected by RT-PCR. RESULTS: The results of histo-pathological examination showed that in SiO2 group, lung tissues were injured obviously; the alveolar inflammation with alveolus interval edema and inflammation cell infiltration appeared on the 3rd and 7th days; the alveolus interval became thicker, became thicker, fibroblast and collagen matrix increased markedly on 14th day; the alveolar structure was damaged, alveolar wall thickened obviously, collagen aggravation and pulmonary fibrosis displayed on 28th day. The alveolar inflammation and pulmonary fibrosis in SiO2 plus Sch-B group were significantly less than those in SiO2 group. The expressions levels of TGF-beta1 TGF-betaR II and Smad4 mRNA (TGF-1beta: 1.03 +/- 0.31, 1.33 +/- 0.39,1.08 +/- 0.26, 0.82 +/- 0.16, TGF-betaR II: 0.65 +/- 0.11, 0.80 +/- 0.16, 0.83 +/- 0.24, 0.62 +/- 0.15, Smad4:0.87 +/- 0.15, 0.68 +/- 0.11, 0.78 +/- 0.19, 0.30 +/- 0.08) in SiO2 group were significantly higher than those in the control group (TGF-beta1:0.59 +/- 0.22, 0.55 +/- 0.25, 0.56 +/- 0.20, 0.55 +/- 0.12, TGR-betaR II :0.28 +/- 0.13, 0.31 +/- 0.15, 0.34 +/- 0.15, 0.27 +/- 0.09, Smad4:0.23 +/- 0.11, 0.40 +/- 0.12, 0.39 +/- 0.12, 0.18 +/- 0.06) (P < 0.01 or P < 0.05), but the expression level of TGF-beta1 mRNA was the highest on the 7th day. The expression levels of TGF-beta1 and Smad4 mRNA (TGF-beta1:0.68 +/- 0.28, 0.88 +/- 0.25, 0.75 +/- 0.11, 0.61 +/- 0.14,Smad4:0.25 +/- 0.12, 0.45 +/- 0.09, 0.44 +/- 0.07, 0.21 +/- 0.04) in SiO2 plus Sch-B group were significantly lower than those in SiO2 group (P < 0.01 or P < 0.05 ), but there were no significant differences of the TGFbetaR II mRNA expression levels between SiO2 group and SiO2 plus Sch-B group. CONCLUSION: Sch-B can reduce the pulmonary fibrosis induced by SiO2 through inhibition of the mRNA express of TGF-beta1 and Smad4 in the lung tissue, modulating the TGF-beta1/Smad4 signal transduction pathway and inhibiting the target gene activation.

Impact of microalgae species and solution salinity on algal treatment of wastewater reverse osmosis concentrate.

Six common microalgal species, including freshwater microalgae Scenedesmus abundans, Chlorella vulgaris, Chlamydomonas reinhardtii and Coelastrum microporum, and marine microalgae Nannochloropsis salina and Dunaliella tertiolecta, were tested in batch treatment to identify the most promising species for remediating a municipal wastewater reverse osmosis concentrate (ROC). Selected species were then studied at different ROC salinity levels (5, 10, and 15 g TDS/L) in semi-continuous treatment to evaluate their potential for nutrient remediation, and biogas production through anaerobic digestion. S. abundans, C. vulgaris, and N. salina showed higher potential for growth and nutrient remediation under salinity stress. Further tests revealed that N. salina adapted well to ROC conditions, and S. abundans could grow better and had higher tolerance to the elevated salinity than C. vulgaris. S. abundans and N. salina performed better for removing nutrients and organic matter (11.5-18 mg/L/d TN, 7.1-8.2 mg/L/d TP, and 8.6-12.4 mg/L/d DOC). Increasing salinity led to growth inhibition and N uptake reduction for freshwater species but had no significant effect on TP removal. Biochemical methane potential tests showed the algal biomass produced a significant amount of methane (e.g., up to 422 mL CH4/g VS for N. salina), suggesting the algae generated from the ROC treatment could produce significant amounts of energy through anaerobic digestion without the need for pretreatment. This study showed the environmental and economic potential of the algal system for future applications.

Quantification of seasonal photo-induced formation of reactive intermediates in a municipal sewage lagoon upon sunlight exposure.

Photochemically produced reactive oxygen species in wastewater lagoons upon sunlight exposure are important in the attenuation of emerging contaminants (ECs). The production of reactive radicals in wastewater lagoons depends on both environmental factors and the composition of effluent organic matter (EfOM) in the wastewater. Knowing the steady state concentrations of these reactive species produced in a particular lagoon wastewater is critical to the prediction of the persistence and attenuation of ECs in that sunlit wastewater treatment lagoon. This study quantified the formation of four photochemically produced reactive intermediates (PPRIs): hydroxyl radical, carbonate radical, singlet oxygen, and triplet excited state EfOM in 11 samples collected from a municipal wastewater lagoon over a full year. The temporal distribution of these key PPRIs in the lagoon under investigation was determined in relation to sunlight irradiance, wastewater composition and temperature. Greater sunlight intensity led to greater PPRI production over the year. Increasing wastewater temperature from 12 to 25 °C led to greater production of singlet oxygen, a moderate decrease in hydroxyl radical and increase in triplet excited state EfOM, and minimal impact on carbonate radical production. The optical properties of the lagoon wastewater of Napierian absorption coefficient (A300) and E2:E3 ratio could be used as indicators of the formation of singlet oxygen (Pearson's r = 0.79) and triplet excited EfOM (Pearson's r = 0.76) produced upon solar irradiation. The concentration of carbonate radical formed was strongly correlated to the nitrate level in the wastewater (Pearson's r = 0.85). The findings could be used for modelling the seasonal sunlight-induced photolysis process of ECs during lagoon-based wastewater treatment, with a view to optimising the treatment process, predicting the efficacy of EC removal, and risk assessment of the treated water.

Treatment of wastewater reverse osmosis concentrate using alginate-immobilised microalgae: Integrated impact of solution conditions on algal bead performance.

Alginate can be used for entrapment of microalgal cells in gel beads to achieve high-rate treatment of wastewater and can overcome the difficulties of cell separation that would occur in suspended microalgae treatment systems. The potential for alginate beads to disintegrate in the presence of high ion concentrations could limit the use of alginate entrapment for treating municipal wastewater reverse osmosis concentrate (ROC). The combined effect of the pH, alkalinity, and salinity of the ROC that impact the physical stability, chemical characteristics, biomass production, and nutrient removal performance of alginate-entrapped Chlorella vulgaris for treating the ROC was investigated. Water adsorption resulting from the loss of calcium from the alginate matrix was the initiating cause of reduction of the algal bead stability. The combination of alkalinity >400 mg/L and pH ≥9.5 led to a >65% reduction in compressive strength and thus disintegration of beads during ROC treatment. However, alginate beads of C. vulgaris were sufficiently stable and were capable of nutrient remediation (up to 100% TP and 85% TN per treatment cycle of 48 h over a 10-day period) and biomass production (up to 340 mg/L/d) when salinity, pH, and alkalinity levels were <8 g TDS/L, 7-9.5, and <400 mg/L, respectively. Empirical models that were developed and validated could enable the prediction of the performance of the algal beads for various ROC compositions. This study enhances the insight and decision-making regarding the feasibility of the alginate-immobilised microalgal system for treating municipal wastewater ROC streams.

Recovery and reuse of alginate in an immobilized algae reactor.

The use of microalgae for nutrients removal from wastewater has attracted more attention in recent years. More specifically, immobilized systems where algae cells are entrapped in beads in a matrix of a polysaccharide such as alginate have shown a great potential for nutrients removal from wastewater to low levels with reduced retention times and hence smaller footprint. However, a significant operational cost in the up-scaling of alginate-immobilized algae reactors will be the gelling agent alginate. To reduce expenditure of this consumable a proof-of-concept is given for an alginate recycling method using sodium citrate as a dissolving agent. Using algae beads made from virgin and recycled alginate yielded comparable removal rates for both phosphorus and nitrogen compounds from wastewater. At labscale, an alginate recovery of approximately 70% can be achieved which would result in a net operational cost reduction of about 60%.

[Effect of Schisandrin B on mitogen-activated protein kinases and nuclear factor-kappaB in rat lungs exposed to silica].

OBJECTIVE: To investigate the effect of Schisandrin B on mitogen-activated protein kinases (MAPKs) and nuclear factor-KB in rat lungs exposed to silica. METHODS: 92 Wistar rats were randomly divided into four groups: Control (20), Silica (30), Sch-B treated 1 group (Sch-B 1) (24) and Sch-B treated 2 group (Sch-B 2)(18). Silicotic animal models received an intratracheal injection of silica. From the first day after model establishment, rats in Sch-B 1 were treated intragastrically with Sch-B at a dose of 80 mg/kg, once daily. From the 8th day after model establishment, rats in Sch-B 2 were treated intragastrically with Sch-B at a dose of 80 mg/kg, once daily. 6 rats in Sch-B 1 were sacrificed on the 3rd, 7th, 14th and 21st days, and 6 rats in Sch-B 2 on the 14th, 21st and 28th days, 4 Control rats, 6 silica rats on the 3rd, 7th, 14th, 21st and 28th days accordingly, lungs were collected. Right lung for protein extraction, the phosphorylation level of extracellular signal-regulated protein kinase, c-Jun NH2-terminal amino kinase and p38 in lungs were detected by Western Blot. Left lung was fixed by neutral formalin. The ratio of nuclear transfer of NF-kappaB was evaluated by immunohistochemistry. RESULTS: 1. The phosphorylation level of ERK1/2 in Sch-B 1 on 3rd, 7th, 14th and 21st (0.974 +/- 0.169, 0.987 +/- 0.149, 0.920 +/- 0.092 and 0.884 +/- 0.078) and Sch-B 2 on 14th, 21st and 28th (1.012 +/- 0.050, 1.167 +/- 0.083 and 1.002 +/- 0.060) were significantly lower than in silica groups P < 0.05 or P < 0.01); The phosphorylation level of JNK1 in Sch-B 1 reached its summit on 7th day (P < 0.01 ), and that in Sch-B 2 on 14th, 21st and 28th (0.882 +/- 0.064, 0.802 +/- 0.061, 0.792 +/- 0.015) was lower than Silica groups at every time points (P < 0.01); The phosphorylation level of p-p38 in Sch-B 1 was higher than silica group on 3rd day (0.309 +/- 0.045) and lower on 7th, 14th and 21st day, but that in Sch-B 2 were lower and lower. 2. The ratio of nuclear transfer of NF-KB in Sch-B 1 on 3rd, 7th, 14th and 21st [(13.54 +/- 5.36)%, (21.01 +/- 6.43)%, (30.55 +/- 6.44)%, (37.39 +/- 9.32)%] was lower than that in silica groups (P < 0.01); but in Sch-B 2, it was lower than silica group on the 21st [(44.33 +/- 22.88)%] and higher on the 28th day [(58.52 +/- 14.57)%] (P < 0.01). CONCLUSIONS: Sch-B has some depression effects on the activation of MAPKs in rat lungs exposed to silica. The nuclear transfer of NF-kappaB could be suppressed by Sch-B in the initial stage of rat lungs exposed to silica. Protection of Sch-B against silica induced lung injury in rats may be via MAPKs and NF-kappaB signal transduction pathway.