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25201. 题目: Humic substances in Fluvisols of the Lower Vistula floodplain, North Poland
文章编号: N18060801
期刊: Environmental Science and Pollution Research
作者: Magdalena Banach-Szott, Krystyna Kondratowicz-Maciejewska, Miros?aw Kobierski
更新时间: 2018-06-08
摘要: The present study describes properties of humic substances of the Fluvisols (the Lower Vistula, Poland). Fluvisols under agricultural management (arable soil and grassland) were sampled from the surface horizon 50, 200, 600, and 900 m from the Vistula River. The content of carbon in the fractions of humic acids (CHAs), fulvic acids (CFAs), and humins (CHUMIN) as well as the content of dissolved organic carbon (DOC) were assayed. The organic matter of the soils that were sampled 200 m from the river demonstrated a lowest share of the humic acids (HAs) and fulvic acids (FAs). The percentage share of the hydrophilic fractions (HIL) in the HAs and, as a result the value of the HIL/ΣHOB ratio, increased with the distance from the riverbed. The HAs of the soils located further from the riverbed had a higher degree of humification compared to the HAs of the soils that were sampled 50 and 200 m away. Based on the research results, it was determined that the properties of HAs can be used to evaluate the effect of flood events, their location, and scope on the transformation of the organic matter in fluvial sediments.

25202. 题目: Use of palmitoleic acid and its oxidation products for monitoring the degradation of ice algae in Arctic waters and bottom sediments
文章编号: N18060705
期刊: Organic Geochemistry
作者: Jean-Fran?ois Rontani, Rémi Amiraux, Catherine Lalande, Marcel Babin, Hak-Ryul Kim, Simon T. Belt
更新时间: 2018-06-07
摘要: Degradation of palmitoleic acid (C16:1ω7), the main fatty acid component of sea ice-associated (sympagic) diatoms, was monitored in Arctic sea ice at the beginning of ice melting and in the underlying sinking particles and superficial bottom sediments. In sea ice, degradation of sympagic algae involved biotic oxidation induced by 10S-DOX-like lipoxygenase of unknown salinity-stressed attached bacteria, while photo- and autoxidation were limited. In the water column, strong hydratase and Z/E isomerase activity were observed. Hydration of unsaturated fatty acids seems to be a detoxification strategy, which is essential for bacterial survival when associated with free fatty acid-rich environments such as ice algae. In contrast, Z/E isomerisation of palmitoleic acid was attributed to the release of Fe2+ ions during radical-induced damage of the active site of the bacterial 10S-DOX-like lipoxygenase and Z/E isomerases. Due to the poor physiological state of their attached bacteria resulting from salinity stress in brine channels or toxicity of free ice algae fatty acids, sympagic algae appeared to be only very weakly biotically degraded within the water column. In bottom sediments, free radicals resulting from 10S-DOX-like lipoxygenase activity induced a strong autoxidation of the ice algal material. The presence in bottom sediments of a significant proportion of oxidation products resulting from 10S-DOX-like lipoxygenase activity attested to the strong contribution of sea ice-derived OM released during the early stages of ice melt prior to deposition in the sediments. However, on the basis of the highest fatty acid photooxidation state observed in these sediments, an additional contribution of highly photooxidized material (ice algal material released at the end of ice melting or open water phytoplankton) seems likely. The degradation of hydroperoxides, resulting from biotic and abiotic degradation of palmitoleic acid, appeared to involve: (i) homolytic cleavage of the peroxyl group affording the corresponding hydroxy- and oxoacids, (ii) reduction to the corresponding hydroxyacids by peroxygenases, (iii) heterolytic proton-catalysed cleavage and (iv) conversion to allylic 1,4-diols by diol synthases and hydroperoxide isomerases.

25203. 题目: Enhancement of surfactant biodegradation with an anaerobic membrane bioreactor by introducing microaeration
文章编号: N18060704
期刊: Chemosphere
作者: Zhenmin Cheng, Yuansong Wei, Qingqing Zhang, Junya Zhang, Tiedong Lu, Yuanmei Pei
更新时间: 2018-06-07
摘要: In controlled ecological life support system (CELSS), 100% water recycle efficiency is needed. Both water and nutrients in wastewater needs reclaiming. In an anaerobic membrane bioreactor (AnMBR) designed to hydrolyze organic matters and convert organic nitrogen, accumulation of anionic surfactants and organic compounds was observed in the supernatant. To solve the problem, microaeration which had rarely been reported to enhance surfactants biodegradation in anaerobic process was introduced and it was proved to be an effective approach that resulted in concentrations of surfactants and soluble chemical oxygen demand (SCOD) in the supernatant decreasing from 9000 mg/L and 40000 mg/L to 2000 mg/L and 10000 mg/L, respectively. And the degradations followed the kinetic characteristics of zero order reaction with R2 values of 0.9472 and 0.949. Three-dimensional excitation emission matrix (3D-EEM) analysis revealed that some activities of microbes were activated and enhanced by microaeration, which resulted in the disintegration of aggregates of large molecules, indicated by the size exclusion chromatography (SEC). After the introduction of microaeration, the emerging genera Aquamicrobium, Flaviflexus, Pseudomonas and Thiopseudomonas in the microbial community might be responsible for the effective biodegradation of the surfactants.

25204. 题目: Photocatalytic degradation of organic pollutants in wastewater with g-C3N4/sulfite system under visible light irradiation
文章编号: N18060703
期刊: Chemosphere
作者: Yi Wei, Qiancheng Zou, Peng Ye, Manye Wang, Xiaoxia Li, Aihua Xu
更新时间: 2018-06-07
摘要: To develop low cost and high efficient sulfate radical (SO4 -) based advanced oxidation processes (AOPs) for rapid remediation of contaminated waters is of great interest. In this study, a green and novel SO4 - based AOPs, in situ visible light activation of sulfite by graphitic carbon nitride (g-C3N4), for the degradation of organic pollutants is reported. The g-C3N4+HSO3 -+ Vis system could achieve remarkably enhanced degradation of organic pollutants such as organic dyes and phenol in aqueous solution. The excellent reusability of the metal free catalyst was also observed during ten successive cycles. The efficiency of the system was dependent on the reaction conditions, which first increased and then decreased with the increase of HSO3 - concentration and initial solution pH. The addition of HCO3 - stimulated the pollutant degradation, but other water matrix components such as Cl and humic acid showed nearly no influence on the reaction. The mechanism investigations suggested that sulfite is oxidized in the system to sulfite radicals, which then react with dioxygen and superoxide radicals to form SO5 - radicals and HSO5 - respectively. SO5 - radicals can be also reduced by sulfite or photoelectron to HSO5 -. SO4 - radicals were then produced from HSO5 -reduction by photoelectron, and contributed to dye degradation in the system together with superoxide radicals. This study provides a novel new approach for efficient degradation of organic degradation via sulfite activation.
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25205. 题目: Effect of aquatic macrophyte growth on landscape water quality improvement
文章编号: N18060702
期刊: Environmental Science and Pollution Research
作者: Hengfeng Zhang, Yixi Zhao, Hang Yin, Yuanyuan Wang, Huixian Li, Zhanshen Wang, Yongbo Geng, Wenyan Liang, Hongjie Wang
更新时间: 2018-06-07
摘要: The water of urban landscape park is often confronted with microalgal blooms due to its stagnancy. Bioremediation using the combined emergent and submerged plants to control the microalgae growth was investigated in the present study. Two water bodies (Bei and Xin) of Yuyuantan Park in Beijing were selected for the field experiments, and the other lakes with different vegetation of macrophytes were selected as the comparison. The concentrations of chlorophyll a (chl a), chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP), and water temperature and transparency were monitored before and after bioremediation from 2015 to 2017. Results showed that the effects of microalgal inhibition were more significant 2 years after bioremediation. Specifically, the chl a of Dong Lake without any vegetation of macrophytes was up to 65.1 μg/L in summer of 2017, while the Bei and Xin Lakes was only 6.2 and 11.3 μg/L, respectively. In addition, the water quality and transparency also improved, with water bodies being crystal clear. Submerged plants played major roles in microalgal control and water quality improvement, compared to the lakes with only emergent plants. The intensity of humic acid-like substances in three-dimensional fluorescent spectra was stronger for the lakes with submerged plants.

25206. 题目: A simple cleanup method for the removal of humic substances from soil protein extracts using aluminum coagulation
文章编号: N18060701
期刊: Environmental Science and Pollution Research
作者: Manolis Mandalakis, Nicolai S. Panikov, Paraskevi N. Polymenakou, Maria V. Sizova, Aristeidis Stamatakis
更新时间: 2018-06-07
摘要: Soil proteomics, the large-scale characterization of the entire protein complement in soils, provides a promising approach for deciphering the role of microbial functioning in terrestrial ecosystems. However, the extraction of soil proteins in sufficient quantities and of adequate purity remains a challenging task mainly due to the co-extraction of interfering humic substances. Up to now, the treatment of soil extracts with liquid phenol has been the “gold standard” for reducing humics, while the NoviPure cleanup kit was recently launched as a non-toxic approach. The present study describes an alternative method for delivering high-purity proteins based on humic coagulation with trivalent aluminum ions (Al3+). Various experimental parameters were optimized individually in order to maximize protein yield and diminish co-extracted humics. The optimized method was applied on a set of soil samples with diverse physicochemical characteristics and a comparison with the other two techniques was conducted. The amount of residual humics resulting from Al3+-based method was 26 and 35% higher than that from phenol treatment and NoviPure Kit, respectively, but these differences were of marginal statistical significance. With regard to extracted proteins, the average yields of the three methods were comparable, without showing any statistically significant differences. Overall, humic coagulation with Al3+ offers comparable cleanup performance in terms of protein yield and purity, but it is less toxic and less complex than the phenol-partitioning method, whereas it is far less expensive than the NoviPure Kit. The new technique is expected to facilitate the implementation of proteomic studies in soils.

25207. 题目: Characteristics of wet dissolved carbon deposition in a semi-arid catchment at the Loess Plateau, China
文章编号: N18060603
期刊: Biogeosciences
作者: Linhua Wang, Haw Yen, Liding Chen, Xinhui E, and Yafeng Wang
更新时间: 2018-06-06
摘要: Wet dissolved carbon deposition is a critical node of the global carbon cycle, but little is known about dissolved organic and inorganic carbon (DOC and DIC) concentrations and fluxes in the semi-arid areas of the Loess Plateau Region (LPR). In this study, we measured variations in DOC and DIC concentrations in rainfalls at Yangjuangou Ecological Restoration and Soil and Water Observatory. Rainwater samples were collected in 16 rainfall events from July to September and the event-based, monthly concentrations and fluxes of DOC and DIC were quantified. The results showed that the event-based concentrations and fluxes of DOC and DIC were highly variable, ranging from 0.56 to 28.71 mg C L-1 and from 3.47 to 17.49 mg C L-1, respectively. The corresponding event-based fluxes ranged from 0.21–258.36 mg C m-2 and from 4.12 to 42.32 mg C m-2. The monthly concentrations of DOC and DIC were 24.62 and 4.30 (July), 3.58 and 10.52 (August), and 1.01 and 5.89 (September) mg C L-1, respectively. Thus, the monthly deposition fluxes of DOC and DIC were 541.64/94.60, 131.03/385.03, and 44.44/259.16 mg C m-2 for July, August, and September, respectively. In addition, the concentrations of DOC and DIC for the concentrated rainfall season (July–September) in the studied catchment were 7.06 and 7.00 mg C L-1, respectively. The estimated annual wet dissolved carbon depositions were 1.91 and 1.89 g C m-2 yr-1 for DOC and DIC, respectively. The results of this study suggest the variation in concentrations and fluxes of DOC and DIC and explore that these variation may be related to the dissolved carbon source and the rainfall characteristics during the concentrated rainfall season in the semi-arid catchment of the LPR. Furthermore, these results also suggest that dissolved carbon may be an important external input of carbon into terrestrial ecosystems.

25208. 题目: Effects of vegetation and fecal pellets on the erodibility of cohesive sediments: Ganghwa tidal flat, west coast of Korea
文章编号: N18060602
期刊: Environmental Pollution
作者: Ho Kyung Ha, Hun Jun Ha, Jun Young Seo, Sun Min Choi
更新时间: 2018-06-06
摘要: Although the Korean tidal flats in the Yellow Sea have been highlighted as a typical macrotidal system, so far, there have been no measurements of the sediment erodibility and critical shear stress for erosion (τ ce ). Using the Gust erosion microcosm system, a series of field experiments has been conducted in the Ganghwa tidal flat to investigate quantitatively the effects of biogenic materials on the erodibility of intertidal cohesive sediments. Four representative sediment cores with different surficial conditions were analyzed to estimate the τ ce and eroded mass. Results show that τ ce of the “free” sediment bed not covered by any biogenic material on the Ganghwa tidal flat was in the range of 0.1–0.2 Pa, whereas the sediment bed partially covered by vegetation (Phragmites communis) or fecal pellets had enhanced τ ce up to 0.45–0.6 Pa. The physical presence of vegetation or fecal pellets contributed to protection of the sediment bed by blocking the turbulent energy. An inverse relationship between the organic matter included in the eroded mass and the applied shear stress was observed. This suggests that the organic matter enriched in a near-bed fluff layer is highly erodible, and the organic matter within the underlying sediment layer becomes depleted and less erodible with depth. Our study underlines the role of biogenic material in stabilizing the benthic sediment bed in the intertidal zone.
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25209. 题目: Revegetation of the riparian zone of the Three Gorges Dam Reservoir leads to increased soil bacterial diversity
文章编号: N18060601
期刊: Environmental Science and Pollution Research
作者: Qingshui Ren, Changxiao Li, Wenhang Yang, Hong Song, Peng Ma, Chaoying Wang, Rebecca L. Schneider, Stephen J. Morreale
更新时间: 2018-06-06
摘要: As one of the most active components in soil, bacteria can affect soil physicochemical properties, its biological characteristics, and even its quality and health. We characterized dynamics of the soil bacterial diversity in planted (with Taxodium distichum) and unplanted soil in the riparian zone of the Three Gorges Dam Reservoir (TGDR), in southwestern China, in order to accurately quantify the changes in long-term soil bacterial community structure after revegetation. Measurements were taken annually in situ in the TGDR over the course of 5 years, from 2012 to 2016. Soil chemical properties and bacterial diversity were analyzed in both the planted and unplanted soil. After revegetation, the soil chemical properties in planted soil were significantly different than in unplanted soil. The effects of treatment, time, and the interaction of both time and treatment had significant impacts on most diversity indices. Specifically, the bacterial community diversity indices in planted soil were significantly higher and more stable than that in unplanted soil. The correlation analyses indicated that the diversity indices correlated with the pH value, organic matter, and soil available nutrients. After revegetation in the riparian zone of the TGDR, the soil quality and health is closely related to the observed bacterial diversity, and a higher bacterial diversity avails the maintenance of soil functionality. Thus, more reforestation should be carried out in the riparian zone of the TGDR, so as to effectively mitigate the negative ecological impacts of the dam. Vegetating the reservoir banks with Taxodium distichum proved successful, but planting mixed stands of native tree species could promote even higher riparian soil biodiversity and improved levels of ecosystem functioning within the TGDR.

25210. 题目: Chemometric tool to study the mechanism of arsenic contamination in groundwater of Puducherry region, South East coast of India
文章编号: N18060512
期刊: Chemosphere
作者: M. Sridharan, D. Senthil Nathan
更新时间: 2018-06-05
摘要: To understand occurrence, distribution and source of arsenic, 175 groundwater samples from coastal aquifers of the Puducherry region were collected and analyzed for major ions and trace metals. The concentration of As in groundwater of study area ranges from not detectable — 28.88 μg/L during the post-monsoon and not detectable — 36.88 μg/L in the pre-monsoon. The desirable limit for As in groundwater is 10 μg/L as per World Health Organization and Bureau of Indian standard. About 13.64 and 11.50% of groundwater samples shows arsenic concentration higher than recommended limit. Hydrochemical facies which dominate during pre and post monsoon are Na-K-Cl-SO4, Ca-Cl and Ca-Mg-Cl-SO4type and Na-K-Cl-SO4, mixedCa-Na-HCO3, Ca-HCO3 and mixed Ca-Mg-Cl type respectively. The Gibbs diagram suggested that rock-water interaction is major process controlling hydrochemistry of groundwater. From the Pourbaix diagram, it is inferred that H3AsO3 is the principal As species in groundwater. The PHREEQC modelling indicates supersaturation of ferric oxides and hydroxide mineral phases in aquifer system which on reductive dissolution releases arsenic into groundwater. Statistical analysis (Spearman Correlation and Principal Component Analysis) showed that reductive dissolution of As-bearing minerals and Fe-oxyhydroxides in the presence of organic matter is the major process contributing arsenic into groundwater. The relationship between As, K+ and HCO 3 indicates agricultural and competitive exchange process which is an additional contributor of arsenic in groundwater. The sources which act as a sink and responsible for the release of As into the groundwater are marine sediments enriched in As and Fe-bearing minerals and organic matter.
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25211. 题目: Direct Visualization of Individual Aromatic Compound Structures in Low Molecular Weight Marine Dissolved Organic Carbon
文章编号: N18060511
期刊: Geophysical Research Letters
作者: ShadiFatayer, Alysha I.Coppola, FabianSchulz, Brett D.Walker, Taylor A.Broek, GerhardMeyer, Ellen R. M.Druffel, MatthewMcCarthy, LeoGross
更新时间: 2018-06-05
摘要: Dissolved organic carbon (DOC) is the largest pool of exchangeable organic carbon in the ocean. However, less than 10% of DOC has been molecularly characterized in the deep ocean to understand DOC's recalcitrance. Here we analyze the radiocarbon (14C) depleted, and presumably refractory, low molecular weight (LMW) DOC from the North Central Pacific using atomic force microscopy to produce the first atomic‐resolution images of individual LMW DOC molecules. We evaluate surface and deep LMW DOC chemical structures in the context of their relative persistence and recalcitrance. Atomic force microscopy resolved planar structures with features similar to polycyclic aromatic compounds and carboxylic‐rich alicyclic structures with less than five aromatic carbon rings. These compounds comprise 8% and 20% of the measurable molecules investigated in the surface and deep, respectively. Resolving the structures of individual DOC molecules represents a step forward in molecular characterization of DOC and in understanding its long‐term stability.

25212. 题目: Nitrogen and Phosphorus Loads to Temperate Seepage Lakes Associated With Allochthonous Dissolved Organic Carbon Loads
文章编号: N18060510
期刊: Geophysical Research Letters
作者: J. R.Corman, B. L.Bertolet, N. J.Casson, S. D.Sebestyen, R. K.Kolka, E. H.Stanley
更新时间: 2018-06-05
摘要: Terrestrial loads of dissolved organic matter (DOM) have increased in recent years in many north temperate lakes. While much of the focus on the “browning” phenomena has been on its consequences for carbon cycling, much less is known about how it influences nutrient loading to lakes. We characterize potential loads of nitrogen and phosphorus to seepage lakes in northern Wisconsin, USA, based on a laboratory soil leaching experiment and a model that includes landscape cover and watershed area. In these seepage lakes, nutrient concentrations are positively correlated with dissolved organic carbon concentrations (nitrogen: r = 0.68, phosphorus: r = 0.54). Using long‐term records of browning, we found that dissolved organic matter‐associated nutrient loadings may have resulted in substantial increases in nitrogen and phosphorus in seepage lakes and could account for currently observed nutrient concentrations in the lake. “Silent” nutrient loadings to brown‐water lakes may lead to future water‐quality concerns.

25213. 题目: Characterization, origin and aggregation behavior of colloids in eutrophic shallow lake
文章编号: N18060509
期刊: Water Research
作者: Huacheng Xu, Mengwen Xu, Yani Li, Xin Liu, Laodong Guo, Helong Jiang
更新时间: 2018-06-05
摘要: Stability of colloidal particles contributes to the turbidity in the water column, which significantly influences water quality and ecological functions in aquatic environments especially shallow lakes. Here we report characterization, origin and aggregation behavior of aquatic colloids, including natural colloidal particles (NCPs) and total inorganic colloidal particles (TICPs), in a highly turbid shallow lake, via field observations, simulation experiments, ultrafiltration, spectral and microscopic, and light scattering techniques. The colloidal particles were characterized with various shapes (spherical, polygonal and elliptical) and aluminum-, silicon-, and ferric-containing mineralogical structures, with a size range of 20–200 nm. The process of sediment re-suspension under environmentally relevant conditions contributed 78–80% of TICPs and 54–55% of NCPs in Lake Taihu, representing an important source of colloids in the water column. Both mono- and divalent electrolytes enhanced colloidal aggregation, while a reverse trend was observed in the presence of natural organic matter (NOM). The influence of NOM on colloidal stability was highly related to molecular weight (MW) properties with the high MW fraction exhibiting higher stability efficiency than the low MW counterparts. However, the MW-dependent aggregation behavior for NCPs was less significant than that for TICPs, implying that previous results on colloidal behavior using model inorganic colloids alone should be reevaluated. Further studies are needed to better understand the mobility/stability and transformation of aquatic colloids and their role in governing the fate and transport of pollutants in natural waters.
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25214. 题目: New Constraints on the Abundance and Composition of Organic Matter on Ceres
文章编号: N18060508
期刊: Geophysical Research Letters
作者: Hannah H.Kaplan, Ralph E.Milliken, Conel M. O'D.Alexander
更新时间: 2018-06-05
摘要: Near‐infrared reflectance spectra from the Dawn mission at Ceres were recently found to exhibit a 3.4 μm absorption indicative of the presence of aliphatic organic compounds. Constraints on abundance and composition of these organics are necessary to inform discussions of their origin. We model reflectance spectra of organic‐bearing regions on Ceres using laboratory spectra of insoluble organics of known composition extracted from terrestrial sedimentary rocks (i.e., kerogens) and carbonaceous chondrite meteorites (i.e., insoluble organic matter, IOM). The 3.4 μm aliphatic organic absorptions observed in Dawn near‐infrared data are stronger than those observed in lab spectra of carbonaceous chondrites, and modeling requires 45% to 65% spectral fraction of IOM to fit spectra from Ceres. The spectral fraction of kerogen necessary to fit the same Ceres spectra ranges from 5% to 15% depending on the hydrogen to carbon ratio of the kerogen. Any proposed mechanism of organic delivery or formation on Ceres should explain the presence of highly concentrated IOM or why the composition is distinct from meteorite‐derived IOM if lower organic abundances are considered more plausible.

25215. 题目: Effect of organic matter on the performance and N2O emission of a granular sludge anammox reactor
文章编号: N18060507
期刊: Environmental Science: Water Research & Technology
作者: Mingsheng Jia, Celia M. Castro-Barros, Mari Winkler, Eveline Volcke
更新时间: 2018-06-05
摘要: A continuously fed bubble column granular sludge anammox reactor was operated for 405 days to investigate the effect of organic matter on the reactor performance and N2O emission. Results showed that influent COD improved the nitrogen removal of the anammox reactor at low influent COD/TN ratios (ca. 0.1); however, a concurrent increase in N2O emission was observed. The average N2O emission increased by 2.5 times (p < 0.05) with increasing influent COD concentration, accounting for up to 0.46% of the incoming nitrogen load. A generalized method was demonstrated and applied to derive the anammox stoichiometry from experimental data for improved mass balance. Mass balance revealed that approximately 18% of the nitrate produced from anammox conversion was reduced via heterotrophic denitrification to nitrite, and 29% of this produced nitrite was further released as N2O. In addition, it was found that the experimentally measured anammox biomass yield in the overall metabolic reaction has been mistakenly used as the catabolic yield in many modelling studies. Solutions were proposed.
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25216. 题目: Link between dissolved organic matter transformation and process performance in a membrane bioreactor for urinary nitrogen stabilization
文章编号: N18060506
期刊: Environmental Science: Water Research & Technology
作者: Celine Jacquin, Mathias Monnot, Razina Hamza, Yahaut Kouadio, Francois Zaviska, Tony Merle, Geoffroy Lesage, Marc Heran
更新时间: 2018-06-05
摘要: A lab-scale membrane bioreactor was fed with fresh urine collected from source separation public toilets to perform full nitrification, urinary nitrogen stabilization and effluent sanitation. After acclimation, a nitrogen loading rate (NLR) of 1.2 kg TN per m3 d-1 was reached with an average nitrification rate of 98.3%. Dissolved organic matter (DOM) transformation was studied within the MBR to identify biomass activity indicators that could be used for process optimization. By combining three-dimensional excitation emission fluorescence (3DEEM) and liquid chromatography coupled with organic carbon detection, nitrogen detection and UV detection (LC-OCD-OND-UVD), it was possible to investigate the transformation and fate of urine DOM during biological reactions and membrane separation. Results show that urine is mainly composed of low molecular weight molecules (<1000 Da) easily consumed by the active biomass. This consumption came with the production of soluble microbial products (SMP): biopolymers and humic substances. Significant correlations were observed between 3DEEM indicators and the NLR values. Biopolymers were mainly retained by the membrane and tended to accumulate in the reactor, which was of major interest since they were identified as DOM consumed by the active biomass in case of system instabilities. Humic substances were slightly retained by the membrane and mostly implied in irreversible fouling. This original approach allowed highlighting the quick active biomass acclimation under challenging conditions of high strength ammonia solutions such as urine.
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25217. 题目: The performance of a sulfate-radical mediated advanced oxidation process in the degradation of organic matter from secondary effluents
文章编号: N18060505
期刊: Environmental Science: Water Research & Technology
作者: Dayang Wang, Lirong Cheng, Mingming Wang, Xuezhen Zhang, Dong Xue, Wenjing Zhuo, Lei Zheng, Aizhong Ding
更新时间: 2018-06-05
摘要: The effects of sulfate radical-mediated advanced oxidation processes with transition metal and energy activation methods were investigated during effluent organic matter (EfOM) degradation. The results showed that transition metal systems and energy systems performed well with some outstanding EfOM removal efficiencies. Specifically, the EfOM removal rate with the Ag(I)/PS (persulfate) system reached 90%, which was far greater than those of Co(II)/PMS (peroxymonosulfate) (56%) and ZVI (zero valence iron)/PS (58%), respectively. Regarding the energy activation systems, they all exhibited both better combined efficiency and the highest efficiency at strong energy intensity (such as heating at 80 °C or treating with UV at 40 W). Further analysis by UV-visible spectroscopy during the reaction process provided a better understanding of the overall changes in every system.
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25218. 题目: Performance of a seawater-driven forward osmosis process for pre-concentrating digested sludge centrate: organic enrichment and membrane fouling
文章编号: N18060504
期刊: Environmental Science: Water Research & Technology
作者: Minh Truong Vu, Ashley Joy Ansari, Faisal I. Hai, Long Nghiem
更新时间: 2018-06-05
摘要: This study demonstrated the potential of seawater-driven forward osmosis for enriching organic matter in digested sludge centrate. The results indicated that the cellulose triacetate membrane offered better performance than the polyamide membrane in terms of organic materials enrichment, fouling resistance and membrane cleaning efficiency. Membrane fouling decreased the enrichment efficiency of organic matter since the deposition of suspended particulate matter on the membrane surface caused fouling and loss of organic matter from the concentrated sludge centrate. The results showed that increasing the draw solution concentration increased flux but did not aggravate membrane fouling, however, it could reduce the efficiency of physical flushing to recover the flux. Seawater showed comparable forward osmosis performance to that of analytical grade NaCl as draw solutes in terms of flux and organic enrichment. The results also showed that seawater as the draw solution resulted in more membrane fouling and lower flux recovery compared to NaCl.
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25219. 题目: Effect of humic acid & bacterial exudates on sorption-desorption interactions of 90Sr with brucite
文章编号: N18060503
期刊: Environmental Science: Processes Impacts
作者: Hollie Ashworth, Liam Abrahamsen-Mills, Nick Bryan, Lynn Foster, Jonathan R. Lloyd, Simon Kellet, Sarah Heath
更新时间: 2018-06-05
摘要: One of the nuclear fuel storage ponds at Sellafield (United Kingdom) is open to the air, and has contained a significant inventory of corroded magnox fuel and sludge for several decades. As a result, some fission products have also been released into solution. 90Sr is known to constitute a small mass of the radionuclides present in the pond, but due to its solubility and activity, it is at risk of challenging effluent discharge limits. The sludge is predominantly composed of brucite (Mg(OH)2), and organic molecules are known to be present in the pond liquor with occasional algal blooms restricting visibility. Understanding the chemical interactions of these components is important to inform ongoing sludge retrievals and effluent management. Additionally, interactions of radionuclides with organics at high pH will be an important consideration for the evolution of cementitious backfilled disposal sites in the UK. Batch sorption–desorption experiments were performed with brucite, 90Sr and natural organic matter (NOM) (humic acid (HA) and Pseudanabaena catenata cyanobacterial growth supernatant) in both binary and ternary systems at high pH. Ionic strength, pH and order of addition of components were varied. 90Sr was shown not to interact strongly with the bulk brucite surface in binary systems under pH conditions relevant to the pond. HA in both binary and ternary systems demonstrated a strong affinity for the brucite surface. Ternary systems containing HA demonstrated enhanced sorption of 90Sr at pH 11.5 and vice versa, likely via formation of strontium–humate complexes regardless of the order of addition of components. The distribution coefficients show HA sorption to be reversible at all pH values studied, and it appeared to control 90Sr behaviour at pH 11.5. Ternary systems containing cyanobacterial supernatant demonstrated a difference in 90Sr behaviour when the culture had been subjected to irradiation in the first stages of its growth.
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25220. 题目: Experimental methodology to measure the reaction rate constants of processes sensitised by the triplet state of 4-carboxybenzophenone as proxy of the triplet states of chromophoric dissolved organic matter, under steady-state irradiation conditions
文章编号: N18060502
期刊: Environmental Science: Processes Impacts
作者: Marco Minella, Lorenzo Rapa, Luca Carena, Marco Pazzi, Valter Maurino, Claudio Minero, Marcello Brigante, Davide Vione
更新时间: 2018-06-05
摘要: By a combination of transient absorption spectroscopy and steady-state irradiation experiments, we investigated the transformation of phenol and furfuryl alcohol (FFA) sensitised by irradiated 4-carboxybenzophenone (CBBP). The latter is a reasonable proxy molecule to assess the reactivity of the excited triplet states of the chromophoric dissolved organic matter that occurs in natural waters. The main reactive species for the transformation of both phenol and FFA was the CBBP triplet state, despite the fact that FFA is a commonly used probe for 1O2. In the case of FFA it was possible to develop a simple kinetic model that fitted well the experimental data obtained by steady-state irradiation, in a wide range of FFA concentration values. In the case of phenol the model was made much more complex by the likely occurrence of back reactions between radical species (e.g., phenoxyl and superoxide). This problem can be tackled by considering only the experimental data at low phenol concentration, where the degradation rate increases linearly with concentration. We do not recommend the use of 1O2 scavengers/quenchers such as sodium azide to elucidate CBBP photoreaction pathways, because the azide provides misleading results by also acting as a triplet-state quencher. Based on the experimental data, we propose a methodology for the measurement of the CBBP triplet-sensitisation rate constants from steady-state irradiation experiments, allowing for a better assessment of the triplet-sensitised degradation of emerging contaminants.
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