Display omitted
•Biochar was superior to ceramsite for nutrient removal and microbial diversity.•Tidal flow enhanced nutrient removal over intermittent aeration.•Biochar media and intermittent ...aeration could reduce greenhouse gas emissions.•Operation mode shaped bacterial communities in CWs more than media type.•Microbial functions of different CW groups were predicted using Tax4Fun2.
Biochar-based subsurface-flow constructed wetlands (CWs) with intermittent aeration (IA) or tidal flow (TF) oxygen supply strategies were established to treat domestic wastewater. The results showed that biochar achieved higher nutrient removal and lower greenhouse gas (GHG) emissions than ceramsite while supporting more diverse bacterial communities and higher abundances of functional taxa. Both IA and TF effectively enhanced nutrient removal, though the latter was more efficient and practical, and aeration conditions greatly influenced nutrient removal efficiency. GHG emissions were decreased by IA but were slightly increased by TF. Both oxygen supply methods significantly shaped the biofilm microbial communities and influenced biodiversity and richness, with observably higher proportions of potential nitrifiers and denitrifiers present in aerated CWs. Overall, biochar-based CWs operated with oxygen supply strategies provide superior treatment of decentralized wastewater.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Biochar substrates and tidal flow (TF) and intermittent aeration (IA) operation modes have recently been applied to improve the treatment performance of constructed wetlands (CWs), but their roles in ...regulating greenhouse gas (GHG) emissions from CWs are still unclear. In this preliminary study, CO2, CH4 and N2O fluxes and associated microbial characteristics in four groups of subsurface-flow CWs, i.e., ceramsite CWs (C-CWs), biochar-amended CWs (B-CWs), intermittently aerated B-CWs (AB-CWs) and tide-flow B-CWs (TB-CWs), were comparatively investigated. The results showed that biochar amendment significantly mitigated CH4 and N2O fluxes from the CWs by supporting higher abundances of mcrA and nosZ genes and higher ratios of pmoA/mcrA and nosZ/(nirK + nirS), thus reducing global warming potential (GWP, a decrease of 55.8%), in addition to promoting total nitrogen (TN) removal by 41.3%, mainly by increasing the abundances and activities of nitrifiers and denitrifiers. The TF mode efficiently improved nitrogen removal, but it greatly increased GHG fluxes since large amounts of GHGs escaped from the empty CW matrix after water draining. IA abated GHG emissions from the CWs, mainly after aeration. TF and IA decreased the abundances of functional bacteria and archaea related to C and N transformation, except nitrifiers, and shaped the microbial community structures. The application of a biochar substrate and IA mode can facilitate the design and operation of CWs in a more ecologically sustainable way.
Display omitted
•Biochar substrates and tidal flow and intermittent aeration effectively enhanced N removal in CWs.•Biochar mitigates GHG emissions by supporting higher ratios of pmoA/mcrA and nosZ/(nirK + nirS) in CWs.•Intermittent aeration reduced GHG emissions from CWs, mainly after aeration.•GHG emissions from tidal flow CWs largely increased after water draining.•Bacterial and archaeal communities in the CWs were comparatively characterized.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A novel F-POSS based omniphobic membrane for MD was prepared.•Excellent wetting resistance to various low surface tension liquids.•Stable MD performance for desalination of surfactant contained ...wastewater.
A novel omniphobic nanofiber membrane for membrane distillation (MD) was successfully fabricated by one-step electrospinning of PVDF-HFP and fluorinated-decyl polyhedraloligomeric silsesquioxane (F-POSS) colloidal suspension solution. The fabricated F-POSS/PVDF-HFP membrane possessed uniform fiber structures and had extreme high F-POSS concentration on the surface. This F-POSS based membrane exhibited excellent omniphobicity, as indicated by its wetting resistance to different low surface tension liquids, including ethanol with a contact angle of 128.2°. Membrane distillation (MD) experiments showed that the water flux and water quality were stably maintained in highly saline feed solutions containing low surface tension substances, which successfully demonstrated its potential application for desalination of challenging industrial wastewater.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
► β-N-(γ-l(+)-glutamyl)-4-carboxyphenylhydrazine was synthesized by Escherichia coli γ-glutamyltranspeptidase. ► γ-Glutamyltransferase was not inhibited by 4-hydrazinobenzoic acid at 1000mM. ► This ...method would facilitate the synthesis of glutamyl phenylhydrazine analogs.
A new method for the synthesis of β-N-(γ-l(+)-glutamyl)-4-carboxyphenylhydrazine, a precursor of agaritine, is presented. This compound was prepared from l-glutamine and 4-hydrazinobenzoic acid through the transpeptidation reaction catalyzed by the Escherichia coli γ-glutamyltransferase. The optimum reaction conditions for the production of β-N-(γ-l(+)-glutamyl)-4-carboxyphenylhydrazine were 50mM l-glutamine, 500mM 4-hydrazinobenzoic acid and 40U γ-glutamyltransferase/mL at pH 8 and 37°C for 24h. The product was obtained with a conversion rate of 90% (mol/mol). γ-Glutamyltransferase activity was not inhibited by 4-hydrazinobenzoic acid at concentrations up to 1000mM. This simple and efficient method would facilitate the synthesis of glutamyl phenylhydrazine analogs, including agaritine.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBJE, UL, UM, UPCLJ, UPUK
The deep purification of secondary effluent from wastewater treatment plants (WWTPs) is essential for protecting the receiving water environment. Recently, iron-carbon materials have attracted more ...and more attention for treating secondary effluent. In this study, lab-scale iron-carbon microelectrolysis constructed wetlands (Fe–C CWs) filled with iron scraps (ISs) and granular biochar were established to purify secondary effluent with C/N ratios of 0.5–5. Walnut shells or pyrite were amended as organic or inorganic electron donors to enhance nutrient removal and reduce iron consumption. The IS substrate substantially promoted nutrient removal when the C/N ratio ≤2 (20.3–36.5% for nitrogen and 10.4–21.8% for phosphorus) by supplying Fe2+/H2 for autotrophic denitrification and iron compounds for phosphorus sequestration. Walnut shell supplementation further strengthened nutrient removal, achieving excellent effluent water quality. Fe substrate consumption was alleviated by electron donor supplementation. The IS substrate decreased CO2 emissions while increasing CH4 and N2O fluxes of the biochar-based CWs, and pyrite addition mitigated the global warming potential (GWP) of the Fe–C CWs. When the C/N ratio changed from 5.0 to 0.5, the abundance of autotrophic denitrifiers and Fe cycle-related populations dominated by Dechloromonas, Ferritrophicum and Thiobacillus increased notably in ISs-amended CWs, and they were responsible for the efficient nitrogen removal. Fe–C CW supplemented with organic solid wastes presents high potential for advanced purification of low C/N nitrified effluent.
Display omitted
•Autotrophic denitrification dominated in CWs filled with iron scraps (ISs) and biochar at COD/TN ≤ 2.•Walnut shell addition effectively enhanced nutrient removal in Fe–C CWs.•Fe substrate loss was mitigated by electron donor addition.•Pyrite addition reduced greenhouse gas emissions from Fe–C CWs.•IS amendment largely increased the abundance of autotrophic denitrifiers in CWs.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Display omitted
•A novel Hg(II)-volatilizing fungus showed bioremediation potentials.•The mer-mediated detoxification system was responsible for Hg(II) volatilization in fungus.•Resistance of DC-F11 ...to Hg(II) was generally a multisystem collaborative process.
Bioremediation of Hg-contaminated soil using microbe-based strategies is a promising and efficient method as it is inexpensive and not harmful to the environment. In this study, a novel Hg(II)-volatilizing fungus Penicillium spp., DC-F11 was isolated and showed bioremediation potential for reducing Hg(II) phytotoxicity, total Hg, and exchangeable Hg in Hg(II)-polluted soil. Subsequently, the mechanisms of Hg(II) volatilization and resistance involved were investigated using multiple complementary techniques. The fungal cells could detoxify Hg(II) by extracellular sequestration via adsorption and precipitation. Moreover, a comparative transcriptome analysis uncovered the primary intracellular adaptive responses of the DC-F11 to Hg(II) stress, including mer-mediated detoxification system, thiol compound metabolism, and oxidative stress defense and damage repair metabolism. These results showed that the resistance of DC-F11 to Hg(II) was generally a multisystem collaborative process. Here, we report, for the first time, that the mer-mediated detoxification system was responsible for Hg(II) volatilization in fungus. These findings provide a better understanding of the mechanisms involved in Hg(II) volatilization and resistance that occur in fungi and also provide a strong theoretical basis for the future application of fungi in the bioremediation of Hg-polluted environments.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Display omitted
•Bismuth (Bi) material is electrochemically active to Cl− and inert to SO42− ions.•SO42− ions decreases chloride storage capacity in Bi electrode.•Bi can selectively remove Cl− from ...mixed solution with lower SO42− concentration.
Common methods in capacitive deionization (CDI) for selective removal are derived from membrane separation mechanism or size-based intercalation mechanism. In this study, based on the electrochemical activity of bismuth (Bi) material to chloride ions (Cl−) and inertness to sulfate ions (SO42−), Bi electrode is used as anode in CDI to selectively remove Cl− ions from mixed NaCl and Na2SO4 solution. Through the reaction with Bi, Cl− ions are stored in bismuth oxychloride (BiOCl). Results show that Bi electrode exhibits selectivity for Cl− over SO42− with a selectivity coefficient of more than 1.5 in solutions with mole ratio of Cl− to SO42− larger than 1. The selectivity coefficient is greatly dependent on the mole ratio of Cl− to SO42− and increases when the ratio rises. In solution with a fixed Cl−/SO42− mole ratio, higher applied voltage and prolonged time result in higher Cl− ion removal capacity, but not necessarily better selectivity. The highest selectivity coefficient of 4.5 is achieved in 8.5 mM NaCl and 1.1 mM Na2SO4 mixed solution at voltage of 1.6 and 2.0 V after charging for 1 h. These results demonstrate that Bi electrode can selectively remove Cl− ions from mixed solution with a relatively lower concentration of SO42− ions, which provides new insights into ion separation and selective removal by CDI.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Display omitted
•Fe-C substrate notably enhanced CW performance in purifying agricultural runoff.•Organic substrate and denitrifying bacteria addition further improved CW performance.•Fe-C substrate ...and augmentation measures mitigated greenhouse gas emissions from CWs.•The bacterial community in Fe-C substrates was notably distinct from that in gravel.•Unique and shared bacterial genera in different CW groups were identified.
Iron-carbon composite-filled constructed wetlands (Fe-C CWs) were employed to treat agricultural runoff in the winter season in this study, and organic substrates and phosphate-accumulating denitrifying bacteria were supplemented to improve the treatment performance. Fe-C CWs performed significantly better in pollutant removal than the control system filled with only gravel by effectively driving autotrophic denitrification, Fe-based dephosphorization and organic degradation. Organic substrate and functional bacteria addition further augmented the performance, and immobilized bacterial cells were more effective than free cells. Fe-C and organic substrates decreased the greenhouse gas emission fluxes of the CWs, and denitrifier inoculation alleviated N2O emission. The microbial community in the Fe-C substrates showed a very distinct distribution pattern compared to that in the gravel, with notably higher proportions of Trichococcus, Thauera and Dechloromonas. Bioaugmented Fe-C-based CWs are highly promising for agricultural runoff treatment, especially at low temperatures.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Dissolved organic matter (DOM) transported by inflowing rivers can considerably contribute to the organic loadings of lakes. The current study characterized the DOM properties and source ...apportionment in the inflowing rivers of Dianchi Lake, the sixth largest freshwater lake in China suffering from organic pollution, during the rainy season by using spectroscopic and carbon stable isotope techniques, and the regulation role of land use was assessed. The results showed that land use (urbanized, agricultural, or mixed) largely affected DOM properties. Greater concentrations and fluorescence intensities of DOM with low aromaticity and dominant autochthonous sources were observed in the urban rivers than in the agricultural rivers. The proportion of humic-like substances increased, while that of tryptophan-like matter decreased from upstream to downstream of two main urban rivers. DOM in the agricultural rivers was characterized by more amounts of aromatic humic-like substances with dominant allochthonous sources compared to that in the urban rivers. Stable isotope analysis showed that the decomposition of macrophytes and input of terrestrial sources from C3 plant-dominated soil and sewage were the major DOM origins in the rivers. The positive linear relationship between the chemical oxygen demand (COD) concentration and fluorescence intensities of terrigenous DOM components implied the necessity of controlling exogenous inputs to alleviate organic pollution in the Dianchi Lake.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
