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1.
Chemosphere ; 346: 140563, 2024 Jan.
Article En | MEDLINE | ID: mdl-38303400

In this study, we first comprehensively studied peroxymonosulfate (PMS) and peroxydisulfate (PDS) activation mechanisms using N, O codoped sludge biochar (NOSB) to degrade organics from water. Among the catalysts, NOSB with a higher content of graphitic N, optimal edge nitrogen (pyridinic N and pyrrolic N), CO groups, sp2-hybridized C, and rich defects were demonstrated to be a superior catalyst. Therefore, by activating PDS and PMS, NOSB exhibited the highest rate of BPA degradation, which was 22-fold and 13-fold that of pristine sludge biochar, respectively. However, owing to different oxidation potentials and molecular structures, PMS and PDS show different degradation performances due to various catalytic mechanisms occurring, even with the same biochar. Due to the asymmetrical structure of PMS, electrons passed from PMS to NOSB and further generated singlet oxygen (1O2), which governs the degradation of bisphenol A with an auxiliary contribution of single electron transfer. Meanwhile, PDS is reduced at the Lewis basic sites of NOSB, forming inner-surface-bound {PDS-NOSB}, which was oxidizing around neighboring carbon and decomposed targets through transferring single and double electrons. NOSB is promising for practical applications because of its adaptation to a wide pH range, anions, high total organic carbon removal, tunable active sites, and re-usability for degrading organics via PMS/PDS activation. This study unveils knowledge about N, O codoped sludge biochar catalysts for activating PMS/PDS and advocates a great approach for organics' degradation in the environment.


Oxygen , Sewage , Catalytic Domain , Charcoal , Carbon/chemistry , Peroxides/chemistry
2.
Chemosphere ; 339: 139767, 2023 Oct.
Article En | MEDLINE | ID: mdl-37562501

This study assessed the components of anaerobically digested sludge, activated sludge, and microbial and extracellular polymeric substance (EPS) enzymes to identify the mechanisms underlying nitrogen removal and soil regeneration. 16S rRNA gene amplicon-based sequencing was used to determine the microbial community composition and the related National Center for Biotechnology Information (NCBI) protein database was used to construct a conventional library from the observed community. EPS components were identified using gel-free proteomic (Liquid Chromatography with tandem mass spectrometry-LC/MS/MS) methods. Alginate-like EPS from aerobically activated sludge have strong potential for soil aggregation and water-holding capacity, whereas total EPS from anaerobic sludge have significant potential for ammonia removal under salt stress. Fourier transform infrared spectroscopy (FTIR) revealed that both EPS may contain proteins, carbohydrates, humic compounds, uronic acid, and DNA and determined the presence of O-H, N-H, C-N, CO, and C-H functional groups. These results demonstrate that the overall enzyme activity may be inactivated at 30 g L-1 of salinity. An annotation found in Kyoto Encyclopedia of Genes and Genomes (KEGG)- KEGG Automatic Annotation Server (KAAS) revealed that the top two metabolic activities in the EPS generated from the anaerobic sludge were methane and nitrogen metabolism. Therefore, we focused on the nitrogen metabolism reference map 00910. EPS from the anaerobically digested sludge exhibited nitrate reductase, nitrite reductase, and dehydrogenase activities. Assimilatory nitrate reduction, denitrification, nitrification, and anammox removed ammonia biochemically. The influence of microbial extracellular metabolites on water-holding capacity and soil aggregation was also investigated. The KAAS-KEGG annotation server was used to identify the main enzymes in the activated sludge-derived alginate-like extracellular EPS (ALE-EPS) samples. These include hydrolases, oxidoreductases, lyases, ligases, and transporters, which contribute to soil fertility and stability. This study improves our understanding of the overall microbial community structure and the associated biochemical processes, which are related to distinct functional genes or enzymes involved in nitrogen removal and soil aggregation. In contrast to conventional methods, microbial association with proteomics can be used to investigate ecological relationships, establishments, key player species, and microbial responses to environmental changes. Linking the metagenome to off-gel proteomics and bioinformatics solves the problem of analyzing metabolic pathways in complex environmental samples in a cost-effective manner.


Extracellular Polymeric Substance Matrix , Sewage , Sewage/chemistry , Extracellular Polymeric Substance Matrix/metabolism , Biodegradation, Environmental , Ammonia/metabolism , Metagenomics , Proteomics , RNA, Ribosomal, 16S , Tandem Mass Spectrometry , Nitrogen/metabolism , Bioreactors , Waste Disposal, Fluid/methods
3.
Bioresour Technol ; 370: 128532, 2023 Feb.
Article En | MEDLINE | ID: mdl-36574886

An anaerobic membrane bioreactor (AnMBR) with media is an emerging carbon-neutral biotechnology for low-strength wastewater (LSWW) treatment and methane recovery. Understanding metabolic dynamics among methanogens and syntrophic bacteria is important in optimizing the design and operation of AnMBR. However, little is known about it, especially in media-attached microbial communities. This study explored metabolic dynamics to compare media-attached and suspended conditions. Accordingly, metagenomes and metatranscriptomes from AnMBRs with polymeric media and fed with different influent concentrations (350 and 700 mg-COD/L) were analyzed. Metabolic dynamics were profoundly influenced by the different growth habitats and influent conditions, although the applied influent concentrations are within the range of typical LSWW. Metabolic dynamics prediction results suggest that media-attached-growth habitats may have provided a more favorable microenvironment for methanogens to grow and produce methane, especially under low influent conditions. These findings provide significant implications for optimizing floating media design and operation of AnMBR-producing methane from LSWW.


Euryarchaeota , Wastewater , Waste Disposal, Fluid/methods , Anaerobiosis , Methane/metabolism , Bioreactors/microbiology , Euryarchaeota/metabolism , Membranes, Artificial
4.
J Hazard Mater ; 409: 124499, 2021 05 05.
Article En | MEDLINE | ID: mdl-33191022

In this study, the feasibility of the membrane distillation (MD) process as a wastewater reclamation system for portable reuse was investigated. The flux was stably maintained at about 20 L/m2h (LMH) at ΔT 30 °C, compared to higher flux at ΔT 50 °C, which showed a rapid decrease in the flux due to severe fouling. MD produced excellent quality of potable water satisfied the drinking water standards of Korea from effluent of sewage treatment plant (ESTP). The fractions of the hydrophobic OC (HOC) and chromatographic DOC (CDOC) from LC-OCD analysis was firstly suggested to understand different organic transport during the MD process. The transport of organic matters across the MD membrane mitigated at low operation temperature and the transported organics in all the tested waters were mostly volatile low molecular weight organics, aromatic amino acids. All of thirteen selected pharmaceuticals were completely removed by MD, regardless of their properties. In order to retard the membrane fouling of the MD process, coagulation and filtration pre-treatments were applied. The pre-treatment process coupled MD process could successfully remove impurities including NH4-N without severe membrane fouling. Moreover, coagulation pretreatment reduced transport of ammonia due to decrease in pH.


Drinking Water , Pharmaceutical Preparations , Water Purification , Distillation , Feasibility Studies , Membranes, Artificial , Republic of Korea , Wastewater
5.
Water Res ; 185: 116263, 2020 Oct 15.
Article En | MEDLINE | ID: mdl-32798891

This study reports application of KMnO4 pre-oxidation and engineered powdered activated carbon (PAC) adsorption to simultaneously control geosmin, 2-methylisoborneol (2-MIB), and microcystin-LR (MC-LR) in conventional drinking water treatment plants (DWTPs). Pulverization of commercial wood-based PAC (1 mm ZrO2 ball, 12 h) reduced the median size to ~6 µm and resulted in overall enhanced kinetics for adsorption of the algal micropollutants. A series of parametric experiments were performed to estimate minimal contact for KMnO4 (1 mg L-1, 10 minutes) and PAC (20 mg L-1, 40 minutes) prior to coagulation, with the aim to meet guidelines (0.02, 0.02, and 1 µg L-1 for geosmin, 2-MIB, and MC-LR, respectively) at specific influent concentrations (0.1, 0.1, and 100 µg L-1) in surface water matrix. Ball-milling of parent PAC with a low oxygen content (~2.5 w/w%) could avoid interferences from/to the KMnO4 pre-oxidation and subsequent coagulation. Pilot-scale experiments confirmed the compatibility of the combined KMnO4 and PAC at existing DWTPs.


Water Pollutants, Chemical , Water Purification , Adsorption , Charcoal , Manganese Compounds , Oxides , Powders
6.
Bioresour Technol ; 291: 121918, 2019 Nov.
Article En | MEDLINE | ID: mdl-31394487

This study first evaluated the process performances and microbial community structures of anaerobic rotary membrane bioreactor (ARMBR) fed with food waste recycling wastewater (FRW). Three identical ARMBRs were operated under different organic loading rate (OLR) conditions (1.5, 3.0, and 6.0 kg COD m-3 d-1) after the same start-up periods. The start-up performances and archaeal community structures differed among the ARMBRs, probably due to the sudden OLR shock. After the start-up, bio-methane was stably produced until the end of the operational period, with all of the ARMBRs showing >95% COD removal efficiency. Methanosaeta spp. was the predominant methanogen; diverse hydrogenotrophic methanogens co-existed. Bacteroidetes-like bacteria and Candidatus Cloacamonas acted as major fermentative bacteria producing acetate or hydrogen for the growth of methanogens. The results suggest that our ARMBR system can be a promising option to manage high-strength organic wastewater such as FRW.


Microbiota , Wastewater , Anaerobiosis , Bioreactors , Methane , Waste Disposal, Fluid
7.
Bioprocess Biosyst Eng ; 42(7): 1225-1234, 2019 Jul.
Article En | MEDLINE | ID: mdl-30993444

This study compared the performance of microalga growth, nutrient removal, algal organic matter, and energy storage products in mixotrophic, photoautotrophic, and heterotrophic conditions. Scenedesmus obliquus was used as a model species. Mixotrophic condition showed the highest specific growth rate of 0.96 d-1 as well as the fastest nitrogen and phosphorus removal rate of 85.17 mg-N g-cell-1 day-1 and 11.49 mg-P g-cell-1 day-1, respectively, compared with photoautotrophic and heterotrophic conditions. Mixotrophic microalgae had relatively higher carbohydrates and lipids contents (21.8 and 24.0%) than photoautotrophic and heterotrophic conditions. Meanwhile, algal organic matter (AOM) in the medium was produced at the highest level under photoautotrophic condition. Mixotrophic condition was more efficient in terms of microalga growth, nutrient removal, production of energy storage products, and suppression of AOM, and would be adaptable for wastewater treatment process.


Carbohydrates/chemistry , Lipids/chemistry , Microalgae/growth & development , Scenedesmus/growth & development , Wastewater/chemistry , Water Purification , Biofuels , Biomass , Wastewater/microbiology
8.
Chemosphere ; 215: 432-443, 2019 Jan.
Article En | MEDLINE | ID: mdl-30336320

This study focuses on the optimization of synthetic conditions for preparing marine macroalgae-derived activated carbon/iron oxide magnetic composites (AC/Fe-MC) and its feasibility for the removal of acetylsalicylic acid from aqueous media. Response surface methodology coupled with a 3k Box-Behnken design was applied to determine the optimal conditions (independent variables: impregnation ratio, activation temperature, and activation time) towards two response variables (production yield and adsorption capacity). According to the analysis of variance and numerical desirability function approaches, the optimal conditions were impregnation ratio of 2.62:1, activation temperature of 727 °C, and activation time of 129 min. Physicochemical properties of the prepared composite revealed that AC/Fe-MC possesses a porous structure and superparamagnetic property, which substantially contributed to the effective adsorption capacity and separation from the solution using an external magnetic field. Adsorption kinetics and equilibrium studies delineated that the pseudo-second-order and Sips isotherm models represent the adsorption behavior of AC/Fe-MC accurately. The maximum adsorption capacity of AC/Fe-MC was found to be around 127 mg/g at 10 °C, as fitted by Sips isotherm model, which is higher than that of other adsorbents reported in the literature. Intraparticle diffusion and Boyd models suggested that the adsorption process was mainly controlled by film diffusion mechanism. Lastly, thermodynamic and isosteric heat of adsorption analyses demonstrated that the adsorption process was controlled by physisorption and exothermic mechanisms.


Aspirin/isolation & purification , Seaweed/chemistry , Water Pollutants, Chemical/isolation & purification , Adsorption , Aspirin/analysis , Charcoal/chemistry , Hydrogen-Ion Concentration , Kinetics , Magnetics , Porosity , Thermodynamics , Water Pollutants, Chemical/analysis , Water Purification/methods
9.
J Hazard Mater ; 339: 63-72, 2017 Oct 05.
Article En | MEDLINE | ID: mdl-28623724

Antibiotics in the aquatic environment are dispersed through anthropogenic activities at low concentrations. Despite their sub lethal concentration, these biologically active compounds may still have adverse effects to non-target species. This study examined the response of adult zebrafish to 0.1mg/L concentration of clarithromycin, florfenicol, sulfamethazine, and their mixture using environmental metabolomics. Embryo and larvae of the fish were also used to assess fish embryo acute toxicity and behavior tests respectively. The fish embryo toxicity test did not show any inhibition of growth and development of the embryos after 96h of exposure to the antibiotics. Changes in swimming activity were seen in 5-dpf larvae which is believed to be correlated with the length of exposure to the compounds. Meanwhile, environmental metabolomics revealed diverse metabolites and pathways that were affected after 72h of exposure of the adult fish to sub-lethal concentration of the compounds. We found that even at low concentration of the antibiotics, behavioral and metabolic effects were still observed despite the lack of visible morphological changes. Further studies involving other aquatic organisms and bioactive compounds are encouraged to strengthen the findings presented in this novel research.


Anti-Bacterial Agents/toxicity , Embryo, Nonmammalian/drug effects , Water Pollutants, Chemical/toxicity , Zebrafish , Adenosine Diphosphate/metabolism , Animals , Choline/metabolism , Clarithromycin/toxicity , Embryo, Nonmammalian/physiology , Embryonic Development/drug effects , Guanosine/metabolism , Metabolomics , Sulfamethazine/toxicity , Swimming , Thiamphenicol/analogs & derivatives , Thiamphenicol/toxicity , Zebrafish/growth & development , Zebrafish/metabolism , Zebrafish/physiology
10.
Eng Life Sci ; 17(9): 976-980, 2017 Sep.
Article En | MEDLINE | ID: mdl-32624847

Microalgae are gaining importance as a source of high-value bioproducts. However, data regarding optimization of algal productivity via variation of environmental factors are lacking. Here, we evaluated a novel lighting method for the enhancement of biomass and total fatty acid (TFA) productivities during algal cultivation. We cultivated six different algal strains (Chlorella vulgaris KCTC AG10002, Acutodesmus obliquus KGE18, Uronema sp. KGE03, Micractinium reisseri KGE19, Fragilaria sp., and Spirogyra sp.) under various lighting conditions-continuous light (CL), light-dark cycle (LD), and continuous dark (CD)-with or without additional flashing light. We monitored dry cell weight (DCW) and TFA concentrations during cultivation. For each algal strain, the growth rate showed markedly different responses to the various lighting modes. The growth rates of C. vulgaris KCTC AG10002 (1.34-fold DCW increase, LD with flash), A. obliquus KGE18 (5.16-fold DCW increase, LD with flash), Uronema sp. KGE03 (2.77-fold DCW increase, CL with flash), and M. reisseri KGE19 (1.52-fold DCW increase, CL with flash) markedly increased in response to flashing light. Additionally, in some algal strains cultivated under the LD mode, the flashing light treatment induced increased TFA concentrations (C. vulgaris, 1.19-fold increase; A. obliquus, 2.59-fold increase; and M. reisseri, 3.31-fold increase). Phytohormone analysis of M. reisseri revealed increases in growth rate and TFA concentrations, associated with phytohormone induction via flashing light (e.g. 2.93-fold increase in gibberellic acid); hence, flashing light can promote substantial alterations in algal metabolism.

11.
Environ Sci Technol ; 50(14): 7590-600, 2016 07 19.
Article En | MEDLINE | ID: mdl-27389869

This study mainly evaluated the effectiveness of ozonation toward the enhancement of the removal efficiencies of antibiotic-resistant bacteria (ARB), pB10 plasmid transfer, and pB10 plasmids under different pH and suspended solids (SS) and humic acid concentrations. First, chlorination was tested as a reference disinfection process. Chlorination at a very high dose concentration of Cl2 (75 mg L(-1)) and a long contact time (10 min) were required to achieve approximately 90% ARB and pB10 plasmid transfer removal efficiencies. However, even these stringent conditions only resulted in a 78.8% reduction of pB10 plasmid concentrations. In case of ozonation, the estimated CT (concentration × contact time) value (at C0 = 7 mg L(-1)) for achieving 4-log pB10 plasmid removal efficiency was 127.15 mg·min L(-1), which was 1.04- and 1.25-fold higher than those required for ARB (122.73 mg·min L(-1)) and a model nonantibiotic resistant bacterial strain, E. coli K-12, (101.4 mg·min L(-1)), respectively. In preventing pB10 plasmid transfer, ozonation achieved better performance under conditions of higher concentrations of humic acid and lower pH. Our study results demonstrated that the applicability of CT concept in practice, conventionally used for disinfection, might not be appropriate for antibiotic resistance control in the wastewater treatment process. Further studies should be conducted in wastewater engineering on how to implement multiple barriers including disinfection to prevent ARB and ARG discharge into the environment.


Disinfection , Ozone , Drug Resistance, Microbial , Escherichia coli , Humic Substances , Hydrogen-Ion Concentration , Waste Disposal, Fluid , Water Purification
12.
Bioresour Technol ; 202: 125-32, 2016 Feb.
Article En | MEDLINE | ID: mdl-26706726

An anaerobic moving bed membrane bioreactor (AnMBMBR) fed with synthetic domestic wastewater was investigated under hydraulic retention time (HRT) shocks to assess the effects on the microbial (bacteria and archaea) community and reactor performance. 16S rDNA targeted polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) approach was optimized to relate the metabolic and community composition with biogas generation, methane content and COD removal efficiency. From the drastic decrease of HRT (from 8 h to 4 h), the methane production was significantly reduced due to the HRT shock, while the COD removal efficiency was not affected. The enhanced growth of homoacetogenic bacteria, Thermoanaerobacteraceae competes with methanogens under shock period. When the HRT was recovered to 8 h, the methane generation rate was higher than the initial operation before the shock HRT changes, which would be ascribed to the activity of new emerging hydrogenotrophic archaea, Methanocella sp. and Methanofollis sp.


Archaea/metabolism , Bacteria/metabolism , Bioreactors/microbiology , Membranes, Artificial , Anaerobiosis , DNA Fingerprinting , Denaturing Gradient Gel Electrophoresis , Methane/metabolism , Polymerase Chain Reaction , Principal Component Analysis , Sequence Analysis, DNA , Time Factors
13.
Water Res ; 89: 222-31, 2016 Feb 01.
Article En | MEDLINE | ID: mdl-26689659

In this study, we integrated physicochemical and biological strategies for the robust treatment of piggery effluent in which high levels of organic constituents, inorganic nutrients, color, and salts remained. Piggery effluent that was stabilized in an anaerobic digester was sequentially coagulated, micro-filtered, and air-stripped prior to biological treatment with mixotrophic algal species that showed tolerance to high salinity (up to 4.8% as Cl(-)). The algae treatment was conducted with continuous O2 supplementation instead of using the combination of high lighting and CO2 injection. The microalga Scenedesmus quadricauda employed as a bio-agent was capable of assimilating both nitrogen (222 mg N g cell(-1) d(-1)) and phosphorus (9.3 mg P g cell(-1) d(-1)) and utilizing dissolved organics (2053 mg COD g cell(-1) d(-1)) as a carbon source in a single treatment process under the heterotrophic growth conditions. The heterotrophic growth of S. quadricauda proceeded rapidly by directly incorporating organic substrate in the oxidative assimilation process, which coincided with the high productivity of algal biomass, accounting for 2.4 g cell L(-1) d(-1). The algae-treated wastewater was subsequently ozonated to comply with discharge permits that limit color in the effluent, which also resulted in improved biodegradability of residual organics. The integrated treatment scheme proposed in this study also achieved 89% removal of COD, 88% removal of TN, and 60% removal of TP. The advantage of using the hybrid configuration suggests that this would be a promising strategy in full-scale treatment facilities for piggery effluent.


Animal Husbandry , Scenedesmus/metabolism , Waste Disposal, Fluid/methods , Wastewater/chemistry , Animals , Biodegradation, Environmental , Color , Nitrogen/chemistry , Ozone/chemistry , Phosphorus/chemistry , Salinity , Scenedesmus/growth & development , Sus scrofa , Water Pollutants, Chemical , Water Purification/methods
14.
Int J Mol Sci ; 16(4): 7551-64, 2015 Apr 03.
Article En | MEDLINE | ID: mdl-25854426

Water-dispersible MgO nanoparticles were tested to investigate their cytotoxic effects on oxidative stress gene expression. In this in vitro study, genes related to reactive oxygen species (ROS), glutathione S-transferase (GST) and catalase, were quantified using real-time polymerase chain reactions (molecular level) and molecular beacon technologies (cellular level). The monodispersed MgO nanoparticles, 20 nm in size, were used to treat human cancer cell lines (liver cancer epithelial cells) at different concentrations (25, 75 and 150 µg/mL) and incubation times (24, 48 and 72 h). Both the genetic and cellular cytotoxic screening methods produced consistent results, showing that GST and catalase ROS gene expression was maximized at 150 µg/mL nanoparticle treatment with 48 h incubation. However, the genotoxic effect of MgO nanoparticles was not significant compared with control experiments, which indicates its significant potential applications in nanomedicine as a diagnostic and therapeutic tool.


Liver Neoplasms/drug therapy , Magnesium Oxide/pharmacology , Nanoparticles/chemistry , Neoplasms, Glandular and Epithelial/drug therapy , Oxidative Stress/drug effects , Catalase/genetics , Gene Expression Regulation, Neoplastic/drug effects , Glutathione Transferase/genetics , Hep G2 Cells , Humans , In Vitro Techniques , Liver Neoplasms/genetics , Magnesium Oxide/chemical synthesis , Neoplasms, Glandular and Epithelial/genetics , Reactive Oxygen Species/metabolism
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 145: 245-253, 2015 Jun 15.
Article En | MEDLINE | ID: mdl-25791881

Microbial algal system can serve as a potential source for the production of much high value bioproducts and biofuels. The quality and intensity of light are the key elements to optimize the production of algal biomass and fatty acid contents. This study presents the effect of differential LED flashing light conditions on the growth of microalgae, Acutodesmus obliquus. The induced light stress was optimized for its biomass and fatty acid content. The microalgae are exposed to various frequency of intermittent LED flashing light (blue and red lights) at three different phases in the 18 day cell growth (log, lag and stationary phase). The frequency of light flashing rate was adjusted to 120, 10, 5, 3.75, and 1 times per min. The effect of light stress on growth and fatty acids composition of A. obliquus induced an increase in algae growth and fatty acid production. Different optimal timing for light stress was subjected to elucidate the effect of light stress on algae growth and fatty acid production. The results showed an increase in the algae growth (1.2mg/L of chl a content) under light stress condition at FT10 (flashing time, 10 times per min) from the initial day (log phase) compared with the control experiment (0.4 mg/L of chl a content). However, the total fatty acids (71 mg/g) and volumetric FAME production (9.4 ml/l) level was found to be significant under FT5 (flashing time, 5 times per min), adopting flashing light from day 10 (stationary phase). TEM studies also revealed the deposition of lipid to be largest in the 18 day old cells under flashing light (FT5) condition, representing maximum accumulation of lipids bodies (up to 770 nm diameter in particle size) occupying approximately 42% of the total area of the cell.


Biomass , Electronics , Fatty Acids/biosynthesis , Light , Microalgae/growth & development , Microalgae/radiation effects , Stress, Physiological/radiation effects , Cells, Cultured , Lipid Droplets/metabolism , Microalgae/metabolism , Microalgae/ultrastructure , Time Factors
16.
Water Res ; 71: 97-106, 2015 Mar 15.
Article En | MEDLINE | ID: mdl-25600301

A fermentative strategy with an anaerobic moving bed biofilm reactor (AMBBR) was used for the treatment of domestic wastewater. The feasibility of using a membrane separation technique for post-treatment of anaerobic bio-effluent was evaluated with emphasis on employing a membrane distillation (MD). Three different hydrophobic 0.2 µm membranes made of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polypropylene (PP) were examined in this study. The initial permeate flux of the membranes ranged from 2.5 to 6.3 L m(-2) h(-1) when treating AMBBR effluent at a temperature difference between the feed and permeate streams of 20 °C, with the permeate flux increasing in the order PP < PVDF < PTFE. The permeate flux of the PTFE membrane gradually decreased to 84% of the initial flux after the 45 h run for distillation, while a flux decline in MD with either the PVDF or PP membrane was not found under the identical distillation conditions. During long-term distillation with the PVDF membrane, total phosphorus was completely rejected and >98% rejection of dissolved organic carbon was also achieved. The characterization of wastewater effluent organic matter (EfOM) using an innovative suite of analytical tools verified that almost all of the EfOM was rejected via the PVDF MD treatment.


Biofilms , Bioreactors , Distillation/methods , Water Purification/methods , Distillation/instrumentation , Hydrophobic and Hydrophilic Interactions , Membranes, Artificial , Phosphorus/chemistry , Polypropylenes/chemistry , Polytetrafluoroethylene/chemistry , Polyvinyls/chemistry , Waste Disposal, Fluid/instrumentation , Waste Disposal, Fluid/methods , Water Purification/instrumentation
17.
Bioresour Technol ; 172: 321-327, 2014 Nov.
Article En | MEDLINE | ID: mdl-25277260

Despite significant research efforts over the last few decades, membrane fouling in anaerobic membrane bioreactors (AnMBRs) remains an unsolved problem that increases the overall operational costs and obstructs the industrial applications. Herein, we developed a method for effectively controlling the membrane fouling in a sponge-submerged AnMBRs using an anaerobic rotary disk MBR (ARMBR). The disk rotation led the effective collision between the sponge and membrane surface; thus successfully enhanced the membrane permeability in the ARMBR. The effect of the disk rotational speed and sponge volume fraction on the membrane permeability and the relationship between the water flow direction and membrane permeability were investigated. The long-term feasibility was tested over 100days of synthetic wastewater treatment. As a result, stable and economical performance was observed without membrane replacement and washing. The proposed integrated rotary disk-supporting media appears to be a feasible and even beneficial option in the AnMBR technology.


Bacteria, Anaerobic/physiology , Biofilms/growth & development , Bioreactors/microbiology , Equipment Contamination/prevention & control , Membranes, Artificial , Sewage/microbiology , Ultrafiltration/instrumentation , Equipment Design , Equipment Failure Analysis , Rheology/instrumentation , Rotation
18.
Appl Biochem Biotechnol ; 174(4): 1668-1682, 2014 Oct.
Article En | MEDLINE | ID: mdl-25138601

Dilution was employed as a pretreatment strategy to increase light transmittance and decrease ammonia toxicity in piggery effluent prior to the cultivation of microalgae. The dilution effect was quantitatively determined based on both the maximum specific nutrient consumption rate and the maximum growth coefficient to minimize the usage of diluent. The biomass productivity of microalgae was also evaluated to select the best species among the five different candidates examined. A 20-fold dilution of piggery wastewater resulted in decreased chromaticity (584 mg Pt-Co L(-1)) and total nitrogen (76 mg L(-1)), on which the microalgae cultivation was more effective for an algal growth compared to the other dilution factors. If the initial cell concentration of Scenedesmus quadricauda increased, the production of biomass tended to improve. Robust growth and harvesting of S. quadricauda were achieved, and the associated consistent removal of inorganic nutrients was accomplished during the semi-continuous cultivation of the best species.


Livestock , Medical Waste Disposal/methods , Microalgae/growth & development , Scenedesmus/growth & development , Wastewater/microbiology , Water Purification , Animals
19.
Bioresour Technol ; 159: 128-35, 2014 May.
Article En | MEDLINE | ID: mdl-24632635

The feasibility of using ozonation pretreatment was investigated for a better performance of post microalgae-based wastewater remediation when treating piggery effluent which was anaerobically digested and subsequently micro-filtered. Ozonation pretreatment at a dose of 1.1mg-O3 mg-C(-1) or higher significantly improved the transmittance of light illumination through the mixed liquor by decolorizing the piggery effluent as culture media, which resulted in increasing both the productivity of algal biomass and the associated removal of inorganic nutrients from the effluent. Ozonation also converted refractory organic constituents in the piggery effluent to a large number of biodegradable fractions via both partial-mineralization and low-molecularization. These fractions were facilely removed through biological assimilation during the mixotrophic cultivation of a microalga S. quadricauda. The results revealed that ozonation could be one of the most promising strategies for the pretreatment of highly-colored piggery effluent prior to algae-based wastewater treatment.


Animal Husbandry , Microalgae/metabolism , Organic Chemicals/isolation & purification , Ozone/chemistry , Wastewater/chemistry , Water Pollutants, Chemical/isolation & purification , Animals , Biodegradation, Environmental , Microalgae/cytology , Microalgae/growth & development , Molecular Weight , Spectrometry, Fluorescence , Sus scrofa , Waste Disposal, Fluid
20.
Bioresour Technol ; 150: 242-8, 2013 Dec.
Article En | MEDLINE | ID: mdl-24177157

In this study, the microalgae culture system to combined active treatment system and pipe inserted microalgae reactor (PIMR) was investigated. After pretreated AMD in active treatment system, the effluent load to PIMR in order to Nephroselmis sp. KGE 8 culture. In experiment, effect of iron on growth and lipid accumulation in microalgae were inspected. The 2nd pretreatment effluent was economic feasibility of microalgae culture and lipid accumulation. The growth kinetics of the microalgae are modeled using logistic growth model and the model is primarily parameterized from data obtained through an experimental study where PIMR were dosed with BBM, BBM added 10 mg L(-1) iron and 2nd pretreatment effluent. Moreover, the continuous of microalgae culture in PIMR can be available. Overall, this study indicated that the use of pretreated AMD is a viable method for culture microalgae and lipid accumulation.


Acids/chemistry , Bioreactors , Metals/isolation & purification , Microalgae/metabolism , Mining , Waste Disposal, Fluid/instrumentation , Water Pollutants, Chemical/isolation & purification , Batch Cell Culture Techniques , Biodegradation, Environmental/drug effects , Biomass , Hydrogen-Ion Concentration , Iron/pharmacology , Kinetics , Lipids/analysis , Microalgae/drug effects , Microalgae/growth & development , Time Factors , Wastewater/chemistry
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