Removal of Heavy Metal Ion in Wastewater by Dendritic Nano-Structured Complex Material.

The specific adsorbents for the removal of heavy metal were synthesized by polyamidoamine dendrimer and blast furnace slag, and their physico-chemical properties were evaluated in this study. The batch experiment was evaluated the adsorptive water treatment capability of adsorbent, and the zeta potential and surface morphology were analyzed for evaluating of the material. In result, 10% volume loading adsorbent presented the high yields of heavy metal adsorption in water phase, and Cr (III) interacted highly with dendrimer adsorbents. Furthermore, it was evaluated that the adsorption properties of dendrimer adsorbent were increased with increasing the ligand-to-metal charge-transfer.

Reduction of Fluoride in Water Phase by Micro-Nano Bubble Pretreatment Process.

Fluoride is important to aquatic environment and health aspects, and the optimal fluoride concentration in water is below 1 mg/L. In this study, the micro-nano bubble pretreatment was applied to remove fluoride ions in the water phase. The pH control by calcium hydroxide (Ca(OH)2), and coagulation processes with poly aluminum chloride (PAC), aluminum sulfate (Alum), F900 and two kinds of polymer named as A-polymer and A430P polymer were applied for the pretreated wastewater. In results, the combination of PAC and A430P polymer with micro-nano bubble pretreated wastewater showed a higher fluoride removal than the case of other combinations. In chemical oxygen demand (COD) removal, the combination of Alum and A430P polymer with micro-nano bubble pretreated wastewater showed the best removal efficiency (64.6%) while the COD removal without pretreatment was 71.4% for fluoride and 57.2% for COD.

Nano-Sized Fume Biogas Production from Food Waster Using Semi-Continuous Anaerobic Digester.

In this study, the nano-sized fume biogas production from food waste was investigated using lab scale semi-continuous stirred tank reactor (SCSTR) at 35 °C with 30d HRT and 30L working volume. The mesophilic digestion test was performed with three different feed materials (food waste) and food to microorganism (F/M) ratios (0.13, 0.34, and 0.27) in the same experiment. The results showed that the F/M ratios significantly affected the biogas production rate. The highest production rate was obtained at F/M ratio of 0.13. Nano-sized fume biogas produced in anaerobic digestion consists of 68.7% CH4, 31.2% CO2 and 30~200 nm particle. The average nano-sized fume biogas and methane production of digester were 29.96 L/Kg versus day-1 and 20.58 L/Kg versus day-1, respectively. The CH4 could be calculated as the heat energy 1.85 Kcal/Kg VS day-1. The digestion was operated without addition of chemicals or nutrients into the system.

Environmental Applications of Nano-Sized Recycled Aggregates: The Effect of Sterilization and Adsorption.

To evaluate the sterilize efficiency of nano-sized recycled aggregates (RAs), several types of RAs were examined for the purpose of environmental stamping out procedure. The poultry (e.g., chicken) was selected as a target livestock of epidemic disease, and the blast furnace slag (BFS), fly ash (FA), slaked lime (SL), nano-cerium (n-Ce) and shell (Sh) were used as the RAs materials. The fermented solution of effective microorganisms (EM) was added to decompose the target livestock. Various kinds of lab-scale reactor were operated to examine the effects of RAs volume; high and low volume of RAs (e.g., 1.89 w/v% and 1.14 w/v% of RA in solution, respectively), and the effects of EM concentration (e.g., concentrated solution (100%) and diluted solution (12.5%)) with tested in different reaction time. The number of microorganisms after batch tests was counted for the sterilized effects of RAs, and organic matters (e.g., chemical oxygen demand (COD)) and inorganic matters (e.g., suspended solids (SS), heavy metals and potential ions) were analyzed before and after adsorption process. The cases of SL and n-Ce showed high removal of microorganism in the batch of high concentrated EM for 20 days. However the other RA materials were less effective on the sterilization especially in lower volume of RAs. In diluted EM (e.g., 12.5%) tests, most RAs have high sterilization efficiencies in the short periods of batch reaction regardless of RAs types, and it was more effective with longer reaction time. The BFS and n-Ce exhibited higher surface area than others and they adsorbed highly heavy metals in water. The results suggested that the concentration of target organism was the most important to determine sterilization and adsorption properties of RAs.

Biological Fixed Film.

The review includes scientific literatures published in the year of 2017 regarding the uses of biofilm and bioreactor to treat wastewater. Topics considered are: biofilm formation and factors that impact biofilm formation; extracellular polymeric substance from biofilms; biofilm consortia and quorum sensing; biofilm associated phage; biofilm reactors; and biofilm in bioelectrochemical systems.

The Effects of Pore Volume and Compressive Strength on the Nano-Sized Recycling Material Mixtures.

In this study, the effect on pore volume and compressive strength was investigated using nano-sized blast furnace slag (BFS), fly ash (FA), and desulfurized gypsum (DG). In the chemical compositions of BFS and FA, the sum of the four ingredients, CaO, SiO2, A12O3, and MgO were shown to account for 97% and 87%, respectively. Particles smaller than 50 nm were shown to be distributed in the range of 47.9% to 50.7%, particles larger than 50 nm but smaller than 100 nm were distributed in the range of 19.0% to 29.1%, and particles sized 100 nm or larger were shown to be distributed in the range of 21.3% to 23.2%. As a result of analysis carried out using an scanning electron microscope (SEM), it was found that BFS, FA, and DS are mixtures of smooth spherical particles and unevenly shaped materials. As to the dependence of pore volume, which depends on pore size and compressive strength, the volume of pores of sizes between 3 and 10 nm showed a proportional trend where volume increases and, as a result, compressive strength also increases as the material age increases. Moreover, the volume of pores sized between 10 and 100 nm showed an inversely proportional trend where volume decreases and, as a result, compressive strength also decreases as the material age increases.

Biological Fixed Film.

The review includes scientific and technical literature published in the year of 2016 regarding the uses of biofilm and bioreactors to treat wastewater. Topics considered are: biofilm formation and factors that impact biofilm formation; extracellular polymeric substances (EPS) from biofilms; biofilm consortia, quorum sensing and quenching; biofilm reactors and biofilm in bioelectrochemical systems.

Co-adsorption of Trichloroethylene and Arsenate by Iron-Impregnated Granular Activated Carbon.

Co-adsorption of trichloroethylene (TCE) and arsenate [As(V)] was investigated using modified granular activated carbons (GAC): untreated, sodium hypochlorite-treated (NaClO-GAC), and NaClO with iron-treated GAC (NaClO/Fe-GAC). Batch experiments of single- [TCE or As(V)] and binary- [TCE and As(V)] components solutions are evaluated through Langmuir and Freundlich isotherm models and adsorption kinetic tests. In the single-component system, the adsorption capacity of As(V) was increased by the NaClO-GAC and the NaClO/Fe-GAC. The untreated GAC showed a low adsorption capacity for As(V). Adsorption of TCE by the NaClO/Fe-GAC was maximized, with an increased Freundlich constant. Removal of TCE in the binary-component system was decreased 15% by the untreated GAC, and NaClO- and NaClO/Fe-GAC showed similar efficiency to the single-component system because of the different chemical status of the GAC surfaces. Results of the adsorption isotherms of As(V) in the binary-component system were similar to adsorption isotherms of the single-component system. The adsorption affinities of single- and binary-component systems corresponded with electron transfer, competitive adsorption, and physicochemical properties.

Biological Fixed Film.

The review includes literature published in the year of 2015 regarding the uses of biofilm in full-scale and lab-scale bioreactors to treat wastewater. The topics considered include biofilm formation and factors impacting biofilm formation; extracellular polymeric substance from biofilms; biofilm consortia and quorum sensing; biofilm reactors and biofilm in bioelectrochemical systems.

Biological Fixed Film.

The review includes literatures published in the year of 2014 regarding the uses of biofilm and bioreactor to treat wastewater. Topics considered are: biofilm formation and factors that impact biofilm formation; extracellular polymeric substance from biofilms; biofilm consortia and quorum sensing; biofilm reactors and biofilm in bioelectrochemical systems.

Impact of polymeric membrane filtration of oil sands process water on organic compounds quantification.

The interaction between organic fractions in oil sands process-affected water (OSPW) and three polymeric membranes with varying hydrophilicity (nylon, polyvinylidene fluoride and polytetrafluoroethylene) at different pHs was studied to evaluate the impact of filtration on the quantification of acid-extractable fraction (AEF) and naphthenic acids (NAs). Four functional groups predominated in OSPW (amine, phosphoryl, carboxyl and hydroxyl) as indicated by the linear programming method. The nylon membranes were the most hydrophilic and exhibited the lowest AEF removal at pH of 8.7. However, the adsorption of AEF on the membranes increased as the pH of OSPW decreased due to hydrophobic interactions between the membrane surfaces and the protonated molecules. The use of ultra pressure liquid chromatography-high resolution mass spectrometry (UPLC/HRMS) showed insignificant adsorption of NAs on the tested membranes at pH 8.7. However, 26±2.4% adsorption of NAs was observed at pH 5.3 following the protonation of NAs species. For the nylon membrane, excessive carboxylic acids in the commercial NAs caused the formation of negatively charged assisted hydrogen bonds, resulting in increased adsorption at pH 8.2 (25%) as compared to OSPW (0%). The use of membranes for filtration of soluble compounds from complex oily wastewaters before quantification analysis of AEF and NAs should be examined prior to application.

Three-dimensional volumetric analysis after sinus grafts.

PURPOSE: The purpose of this study was to evaluate the augmentation volume of a sinus graft according to the time and graft materials based on cone-beam computed tomography (CBCT) scans and to assess efficacy of a bioabsorbable membrane. METHODS: Fourteen patients were investigated, and volumetric analysis was performed using OnDemand 3DTM software (Cybermed, Seoul, Korea). CBCT scans were performed on patients before surgery, immediately after surgery, 6 months after surgery, and 1 year after surgery. Following this analysis, the volumetric data were compared with the actual grafted volumes. Bioabsorbable membranes were used in all patients to promote the protection of sinus membranes and to guide bone regeneration. RESULTS: Overall, the average percent volume of graft material that remained 6 months after implantation was 82.0%, and the average percent volume of graft material that remained 1 year after surgery was 60.4%. These reductions in the volume of graft material from immediately after surgery until 6 months or 1 year after surgery were shown to be statistically significant (P = 0.002 and P < 0.001, respectively). CONCLUSION: The slight differences observed among the data indicate that volumetric analysis performed using CBCT can provide highly accurate data. A significant difference was observed in volumetric change over time, but no significant differences were observed between materials. No significant relationship was observed between the resorption of grafted bone and the success rate.

Desalination of oil sands process-affected water and basal depressurization water in Fort McMurray, Alberta, Canada: application of electrodialysis.

The high content of inorganic species in water used to extract bitumen from the Alberta oil sands and in the groundwater below the oil sands is an increasing environmental concern. These water matrices require treatment before they can be reused or safely discharged. Desalination of the oil sands process-affected water (OSPW) and groundwater, or basal depressurization water (BDW), can be accomplished with deionization techniques such as electrodialysis (ED). In order to achieve the effective ED treatment, OSPW and BDW were pretreated with coagulation-flocculation-sedimentation to remove solid species and turbidity. We demonstrated that a conductivity range for industrial reuse of OSPW and BDW can be achieved with the ED treatment and showed the possibility of applying ED in the oil sands industry. A continuous ED system that reuses the diluate stream as a source for the concentrate stream was designed. The cost of a hypothetical ED water treatment plant in Fort McMurray, Alberta, was estimated to be C$10.71 per cubic meter of treated water.

Machine learning approaches to predict the photocatalytic performance of bismuth ferrite-based materials in the removal of malachite green.

This study focuses on the potential capability of numerous machine learning models, namely CatBoost, GradientBoosting, HistGradientBoosting, ExtraTrees, XGBoost, DecisionTree, Bagging, light gradient boosting machine (LGBM), GaussianProcess, artificial neural network (ANN), and light long short-term memory (LightLSTM). These models were investigated to predict the photocatalytic degradation of malachite green from wastewater using various NM-BiFeO3 composites. A comprehensive databank of 1200 data points was generated under various experimental conditions. The ten input variables selected were the catalyst type, reaction time, light intensity, initial concentration, catalyst loading, solution pH, humic acid concentration, anions, surface area, and pore volume of various photocatalysts. The MG dye degradation efficiency was selected as the output variable. An evaluation of the performance metrics suggested that the CatBoost model, with the highest test coefficient of determination (0.99) and lowest mean absolute error (0.64) and root-mean-square error (1.34), outperformed all other models. The CatBoost model showed that the photocatalytic reaction conditions were more important than the material properties. The modeling results suggested that the optimized process conditions were a light intensity of 105 W, catalyst loading of 1.5 g/L, initial MG dye concentration of 5 mg/L and solution pH of 7. Finally, the implications and drawbacks of the current study were stated in detail.

Evaluation of membrane fouling for in-line filtration of oil sands process-affected water: the effects of pretreatment conditions.

Membrane filtration is an effective reclamation option for oil sands process-affected water (OSPW). However, fresh OSPWs contain suspended solids and inorganic constituents in suspended and dissolved forms that can severely foul membranes. Pretreatment of OSPW with coagulation-flocculation (CF) was investigated to determine the effects of different coagulant aids (anionic, cationic, and nonionic polymers) on membrane surface properties and fouling. Our results showed that CF pretreatment effectively enhanced nanofiltration (NF) and reverse osmosis (RO) membrane permeate flux and salt rejection ratio through reducing membrane fouling. It was shown that coagulants and coagulant aids applied to OSPW feedwater can affect membrane physicochemical properties (surface hydrophilicity, zeta potential, and morphology), membrane performance, and the fouling indexes. Membrane rejection of ionic species increased significantly with the inclusion of an anionic coagulant aid and slightly with a cationic coagulant aid. Among three coagulant aids tested, anionic coagulant aids led to the most enhanced membrane performance through increasing membrane surface negativity and decreasing the formation of a fouling layer. Conversely, although cationic coagulant aids were the most effective in reducing OSPW turbidity, the application of cationic coagulant aids promoted the adsorption of foulants on membrane surfaces.

Development of a Polymeric Carbon Nanocomposite Hollow-Fiber Membrane for Wastewater Treatment.

This study investigated experimental parameters to fabricate polymeric carbon nanocomposite hollow-fiber membranes with graphene oxide and multi-walled carbon nanotubes. This case was different from that of flat-sheet type membranes in that the characteristics of the hollow-fiber type membranes were affected by the structure of the spinneret, the flow rate of the injected polymer and draw solution, and the mixing ratio. The membranes were characterized in terms of mechanical strength, porosity, hydrophilicity, and permeate flux using different solutions. The results reveal a mechanical strength of the carbon nanocomposite hollow-fiber membranes that is about 47.8% higher than that of hollow-fiber membranes without carbon nanomaterials. The porosity and surface hydrophilicity changed to produce more applicable membranes for water and wastewater treatment. As for the permeate flux, the nanocomposite membrane with graphene oxide showed a higher flux compared to the multi-walled carbon nanotubes membrane, which could be influenced by structural effects of the carbon materials.

Biological fixed-film systems.

The technical papers published in 2019 regarding wastewater treatment and microbial films were classified into two categories: biofilm and biofilm reactors. The biofilm category includes biofilm formation, biofilm consortia, bacterial signals, biofouling, extracellular polymeric substances, and biofilm membrane bioreactors. The biofilm reactors category provides recent information on rotating biological contactors, fluidized-bed biofilm reactors, integrated fixed-film activated sludge, moving-bed biofilm reactors, packed-bed biofilm reactors, sequencing biofilm batch reactors, and trickling filters.

The Water Quality Management for Recirculating Aquaculture System by Applying Nano Adsorption Technology.

In a fish farm, the water quality is important to ensure fish growth and farm productivity. However, the study of the quality of water using in aquaculture has been ignored until now. Although there are several methods to treat water, nanomaterials have not yet been applied for indoor fish farming because it may difficult to supply a sufficient amount of water, and the operating parameters have not been developed for recirculating aquaculture systems. Nanotechnology can be applied to treat water, specifically through adsorption and filtration, to produce drinking water from surface water and to treat wastewater by processing a high volume of effluent. The adsorption and filtration of seawater has also progressed to allow for desalination of seawater, and this is recognized as a necessary tool for extended treatment protocols of various types of seawater. This study investigated the treatment of aquaculture water using nano-porous adsorbents (e.g., pumice stone) to control the contaminants in seawater in order to maintain the water quality required for aquaculture. The results are used to derive an analytical relationship between the ionic species in aquaculture water, and this provides empirical parameters for a batch reactor for aquaculture. The quality of the influent and effluent for aquaculture is compared using time-series analyses to evaluate the reduction rate of ionic components and thus suggest the optimum condition for fish farming using bioreactor processes.

Recovering Nutrients from Waste Black Water Through Multi-Functional Mesoporous Silica.

In order to prevent the harmful effects in water phase such as eutrophication, industrial and urban sewages must be treated before discharging into the aquatic environment. In this work, amine grafted magnetic nanoporous silica materials are synthesized and applied as an adsorbent for the recovery of nutrients from waste black water. The magnetic force could separate the surface func-tionalized nanoporous silica materials from aqueous medium after treatment, and showed the higher adsorption capacity of nutrients than that of the original mesoporous silica. The multi-functional nanoporous silica adsorbents were effectively removed phosphate and nitrate at 20 °C with the maximum adsorption capacities of 42.5 and 34.9 mg/g, respectively. The overall results indicated that the synthesized multi-functional nanoporous silica sorbents can be a candidate material for the nutrient recovery in wastewater treatment system.

Melanin pigments extracted from horsehair as antibacterial agents.

Here we present the important findings related to biologically derived pigments for potential use as antibacterial agents. Melanin biopigments extracted from Equus ferus hair exhibit a homogeneous elliptical microstructure with highly ordered semicrystalline features. Spectroscopic analysis indicates that melanin contains a high degree of redox active catechol groups, which can produce reactive oxygen species. The antibacterial activity of melanins was tested by incubating Escherichia coli and Staphylococcus aureus with melanins. The results showed 100% bacterial growth inhibition within 4 h. This finding suggests that melanin pigments may serve as naturally occurring antibacterial agents with unique redox chemistry and reactive oxygen species generation capability.