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17441. 题目: Fate and removal of antibiotic resistance genes in heavy metals and dye co-contaminated wastewater treatment system amended with β-cyclodextrin functionalized biochar
文章编号: N20031808
期刊: Science of The Total Environment
作者: Ji-wen Wu, Cong-rong Wu, Chun-shuang Zhou, Li-li Dong, Bing-feng Liu, De-feng Xing, Shan-shan Yang, Jia-ning Fan, Li-ping Feng, Guang-li Cao, Shi-jie You
更新时间: 2020-03-18
摘要: Biochar has been received increasing concerns regarding its environmental effect, which is promising in wastewater treatment. In this study, the performance of β-cyclodextrin functionalized biochar (β-BC) on the removal of antibiotic resistance genes (ARGs) in wastewater treatment under the co-stresses of heavy metals and dye is evaluated. Results show that when 20 mg/L heavy metals (HMs) and 150 mg/L methyl orange (MO) are present in daily fed influent, only 0.05 mg/L HMs residual and 96.79%–98.84% MO removal efficiency achieved in β-BC additive group, compare to 0.16 mg/L and 87.92%–94.11% of that in control, respectively, indicating that β-BC can benefits the performance of contaminants removal. To evaluate the role of β-BC plays on ARGs in multi-contaminants stressed system, tet W, tet M, sul-1, sul-2, blaTEM, oxa-1, qnr-S, erm-B and intI-1 are identified. The relative abundance of all identified ARGs are decreased when β-BC presence compared to the corresponding groups without β-BC additive. The diversity and composition of microbial community are explored and the reduction of potential antibiotic-resistant bacteria is speculated as a driver of ARGs removal. In conclusion, our study demonstrates that β-BC possesses the ability to promote the removal of ARGs during continuous wastewater treatment under HMs-MO co-contaminant.

17442. 题目: Ammonia and phosphorus removal from agricultural runoff using cash crop waste-derived biochars
文章编号: N20031807
期刊: Frontiers of Environmental Science & Engineering
作者: Alisa Salimova, Jian’e Zuo, Fenglin Liu, Yajiao Wang, Sike Wang, Konstantin Verichev
更新时间: 2020-03-18
摘要: Adsorption of biochars (BC) produced from cash crop residuals is an economical and practical technology for removing nutrients from agricultural runoff. In this study, BC made of orange tree trunks and tea tree twigs from the Laoguanhe Basin were produced and modified by aluminum chloride (Al-modified) and ferric sulfate solutions (Fe-modified) under various pyrolysis temperatures (200°C–600°C) and residence times (2–5 h). All produced and modified BC were further analyzed for their abilities to adsorb ammonia and phosphorus with initial concentrations of 10–40 mg/L and 4–12 mg/L, respectively. Fe-modified Tea Tree BC 2h/400°C showed the highest phosphorus adsorption capacity of 0.56 mg/g. Al-modified Orange Tree BC 3h/500°C showed the best performance for ammonia removal with an adsorption capacity of 1.72 mg/g. FTIR characterization showed that P = O bonds were formed after the adsorption of phosphorus by modified BC, N-H bonds were formed after ammonia adsorption. XPS analysis revealed that the key process of ammonia adsorption was the ion exchange between K+ and NH4+. Phosphorus adsorption was related to oxidation and interaction between PO43 and Fe3+. According to XRD results, ammonia was found in the form of potassium amide, while phosphorus was found in the form of iron hydrogen phosphates. The sorption isotherms showed that the Freundlich equation fits better for phosphorus adsorption, while the Langmuir equation fits better for ammonia adsorption. The simulated runoff infiltration experiment showed that 97.3% of ammonia was removed by Al-modified Orange tree BC 3h/500°C, and 92.9% of phosphorus was removed by Fe-modified Tea tree BC 2h/400°C.

17443. 题目: Continuous aridification since the mid-Holocene as the main cause of C 3 /C 4 dynamics in the grasslands of Northeastern China
文章编号: N20031806
期刊: European Journal of Soil Science
作者: N. Li, M. Xie, D. Sack, N. Dubois, X. Yang, G. Gao, D. Li, L. Liu, H. Liu, C. Leng, J. Wang, B. Liu, D. Jie
更新时间: 2020-03-18
摘要: Ecological responses to past climate change as determined from palaeorecords offer insights into responses that may accompany future climate change. In arid and semi‐arid lands, the interactions between regional vegetation and climate change are not yet well understood partly due to a lack of suitable palaeovegetation proxies that can provide accurate and continuous tracers for past vegetation dynamics. To gain a better understanding of long‐term vegetation dynamics, this study employs a multiproxy approach applied to sand‐palaeosol sediments of northeastern China's Songnen grasslands. Phytolith analyses and data on the stable carbon isotope composition (δ13C) of organic matter are used to reconstruct palaeovegetation composition, namely, the changing abundance of C3 and C4 species, whereas a geochemical weathering index (Fed/Fet ratios) tracks past East Asian summer monsoon (EASM) intensity. The phytolith assemblages and indices and δ13C of the soil indicate that C4 species abundance has been increasing in the Songnen grasslands since the mid‐Holocene, although C3 vegetation is still dominant. Statistically significant negative correlations between the δ13C data and Fet/Fed ratios suggest that continuous weakening of the EASM since the mid‐Holocene may be responsible for the 13C‐enrichment of the sediments in the Songnen grasslands. Field vegetation surveys, modern topsoil phytoliths, and δ13C calibration data indicate that the expansion of C4 species since the mid‐Holocene is mainly due to their ability to cope with aridity when growing season temperature is not undergoing a significant decrease. Future precipitation decreases in arid and semi‐arid lands should make C4 species more competitive in the grasslands of Northeastern China. This article is protected by copyright. All rights reserved.

17444. 题目: Soil DOC release and aggregate disruption mediate rhizosphere priming effect on soil C decomposition
文章编号: N20031805
期刊: Soil Biology and Biochemistry
作者: Yanghui He, Weixin Cheng, Lingyan Zhou, Junjiong Shao, Huiying Liu, Huimin Zhou, Kai Zhu, Xuhui Zhou
更新时间: 2020-03-18
摘要: Roots and the associated rhizospheric activities regulate the mineralization of native soil organic matter (SOM), which is referred to as the rhizosphere priming effect (RPE). Although the importance of RPE for carbon cycle has increasingly been recognized, experimental evidence for how soil structural changes modulate the RPE is still unavailable. We addressed this issue by growing soybean plants (C3) in a C4-derived soil in a continuous 13C- labeling greenhouse. We hypothesized that root-induced soil structural change regulated the RPE by destabilizing soil matrix-protected organic carbon. Our results showed that the RPE was tightly coupled with plant photosynthetic activity, the disruption of coarse macro-aggregates, and the increased release of dissolved organic carbon (DOC) from the soil matrix. These findings indicate that living roots together with rhizodeposits not only can directly stimulate rhizospheric microbial activities, but also can make soil matrix-protected organic carbon available to microbial attacks and further enhance the RPE. This study suggests that the RPE on SOM mineralization is intimately linked with the dynamics of soil structures and DOC, which should be considered in future studies on mechanistic understanding and modeling of the RPE.

17445. 题目: Spatiotemporal variations of DOM components in the Kushiro River impacted by a wetland
文章编号: N20031804
期刊: Environmental Science and Pollution Research
作者: Md. Shafiquzzaman, Husnain Haider, Muhammed A. Bhuiyan, Abdelkader T. Ahmed, Saleem S. AlSaleem, Abdul Razzaq Ghumman
更新时间: 2020-03-18
摘要: Dissolved organic matter (DOM) has been recognized as a serious water quality problem in natural water bodies receiving pollution loads from point and nonpoint sources. The present study investigates the spatiotemporal variability of DOM composition in the Kushiro River and its tributaries (Eastern Hokkaido, Japan) impacted by the Kushiro wetland. Water samples were collected in the wet and dry seasons from several locations of the river and analyzed for DOM characteristics by UV–visible and excitation–emission matrix fluorescence spectroscopy techniques and by developing water quality index. Rather than the spatial effect, significant seasonal impacts on DOM pollution in the Kushiro River were observed. Overall concentrations of DOM decreased during the dry season. The increase of specific ultraviolet absorbance in the dry season indicated an increasing trend of humification, aromaticity and molecular weight of DOM. Five fluorescent peaks, including peaks A, C, M, B, and T were predicted by EEM spectra. Peaks A and C were found to be the most dominating peaks in both the seasons and indicated enrichment of humic-like matters in river water. The intensities of poly-aromatic humic substances as well as DOM components of microbial origin increase in the wet season and proteins like autochthonous DOM increase during the dry season. The study recognized the contribution of freshly produced DOM component by the decomposition of wetland plants in wet season and effect of snowfall in the dry season. Analysis of three fluorescence indices revealed that the river water primarily contains terrestrially dominated DOM. A significant impact of the adjacent WWTPs and wetland to the river water DOM were also observed. The water quality index of river water DOM showed low to medium levels of DOM pollution in the Kushiro River.

17446. 题目: Removal of methylene blue dye using rice husk, cow dung and sludge biochar: characterization, application, and kinetic studies
文章编号: N20031803
期刊: Bioresource Technology
作者: Anees Ahmad, Nawaz Khan, Balendu Shekher Giri, Pankaj Chowdhary, Preeti Chaturvedi
更新时间: 2020-03-18
摘要: The present studies aimed for the removal of Methylene blue (MB) dye using the rice husk biochar (RHB), cow dung biochar (CDB) and domestic sludge biochar (SB) synthesized through slow pyrolysis at 500°C. The biochar was used for the adsorption of synthetic aqueous MB dye. The removal efficiencies of MB by CDB, RHB and SB in a batch experiment were 97.0-99.0; 71.0-99.0 and 73.0-98.9 % at conditions, pH (2.0–11.0); Biochar dosage (0.5–6.0 g/100mL) for 5 days. Adsorption isotherm of Langmuir constant (KL) were obtained 0.101, 0.583 and 0.128 for RHB, CDB and SB respectively. Further, adsorption kinetics of pseudo first order for RHB, CDB and SB were 0.068, 0.018, and 0.066 while it was 0.031, 0.023 and 0.273 for pseudo second order kinetics. Thus, CDB was more effective adsorbent for the dye removal. The pHz values were 7.8, 6.3 and 6.0 for the CDB, RHB, and SB, respectively.

17447. 题目: A lignin-biochar with high oxygen-containing groups for adsorbing lead ion prepared by simultaneous oxidization and carbonization
文章编号: N20031802
期刊: Bioresource Technology
作者: Yuan Li, Fei Wang, Yaowen Miao, Yuliang Mai, Huanling Li, Xiaotian Chen, Jiazhi Chen
更新时间: 2020-03-18
摘要: A lignin-biochar with high acidic oxygen-containing groups was produced via a facile simultaneous oxidization and carbonization of pulping lignin by using sulfuric acid for the first time. The lignin-biochars were investigated by 13C NMR, FTIR and XPS, and results demonstrated that treatment by sulfuric acid could oxidize part of aromatic ring side chain to introduce high acidic oxygen-containing group, especially carboxyl group,. Their total acidic oxygen-containing groups of lignin-biochar including –COOH and Ar-OH reached 8.64 mmol/g. Adsorption experiments were carried and the maximum adsorption capacity of lignin-biochar for Pb2+ reached 679 mg/g, which was significantly higher than other lignin-based or carbon adsorbents. Moreover, it could maintain high removal rate at high adsorption capacity. It also demonstrated that adsorption capability was proportional to the accessible carboxyl groups.

17448. 题目: Implication for adsorption and degradation of dyes by Humic acid: light driven of Environmentally persistent free radicals to activate reactive oxygen species
文章编号: N20031801
期刊: Bioresource Technology
作者: Yanzhuo Zhang, Muchen Yin, Xuedi Sun, Jing Zhao
更新时间: 2020-03-18
摘要: Humic acid (HA) was applied as the biosorbent for the adsorption and degradation of dyes in the presence of environmentally persistent free radicals (EPFRs). Scanning Electron Microscope (SEM) analysis showed that the microstructure of the HA surface and the thermal stability was analyzed by thermogravimetric analysis (TGA). Following irradiation, semiquinone EPFRs (g-factor>2.0045) were generated on the HA surface. Both O2 and the addition of H2O2 were able to promote the generation of hydroxyl and superoxide radicals for the degradation of dye in aqueous solution. Furthermore, adsorption was observed to remove large amounts of the dyes, while the instantaneous free radical degradation process reduced the dyes to the lower concentration. In addition, a linear relationship was observed between the consumption of EPFRs and dye degradation rates. In ternary systems, HA conformed to Langmuir (476.19-1250.12 mg/L) and pseudo-second-order kinetic models. This work offers new insights into HA-EPFRs and their potential applications.

17449. 题目: Formation and control of bromate in sulfate radical-based oxidation processes for the treatment of waters containing bromide: A critical review
文章编号: N20031705
期刊: Water Research
作者: Chaoting Guan, Jin Jiang, Suyan Pang, Yang Zhou, Yuan Gao, Juan Li, Zhen Wang
更新时间: 2020-03-17
摘要: Sulfate radical-based advanced oxidation processes (SR-AOPs) show a good prospect for effective elimination of organic contaminants in water due to the powerful oxidation capability and good adaptability of sulfate radical (SO4•−). However, great concerns have been raised on occurrence of the carcinogenic byproduct bromate (BrO3−) in SR-AOPs. The present article aims to provide a critical review on BrO3− formation during bromine (Br)-containing water oxidation by various SR-AOPs. Potential reaction mechanisms are elaborated, mainly involving the sequential oxidation of bromide (Br−) by SO4•− to Br-containing radicals (e.g., bromine atom (Br•)) and then to hypobromous acid/hypobromite (HOBr/OBr−), which acts as the requisite intermediate for BrO3− formation. Some key influencing factors on BrO3− formation are discussed. Particularly, dissolved organic matter (DOM) as a component ubiquitously present in aquatic environments shows a significant suppression effect on BrO3− formation, primarily attributed to the reduction of Br• by DOM to Br−. The reaction of Br• with DOM can hardly produce organic brominated byproducts, while their formation is mainly due to the bromination of HOBr/OBr− generated through nonradical pathways such as the direct reaction of Br− with oxidants (e.g., peroxymonosulfate (PMS)) or other reactive species derived from catalytic activators (e.g., Co(III) in the Co(II)/PMS process). The debromination of brominated pollutants during their oxidation by SO4•− results in the release of Br−, which, however, is not further transformed to BrO3− until coexisting organic matters are mineralized nearly completely. Furthermore, possible strategies for control of BrO3− formation in SR-AOPs as well as the future research needs are proposed.

17450. 题目: Solvent-free synthesis of magnetic biochar and activated carbon through ball-mill extrusion with Fe3O4 nanoparticles for enhancing adsorption of methylene blue
文章编号: N20031704
期刊: Science of The Total Environment
作者: Yanfei Li, Andrew R. Zimmerman, Feng He, Jianjun Chen, Lujia Han, Hao Chen, Xin Hu, Bin Gao
更新时间: 2020-03-17
摘要: Magnetic carbonaceous adsorbents were synthesized by ball-milling biochar (BC) or activated carbon (AC) with Fe3O4 nanoparticles, and their capacities to sorb methylene blue (MB) from water were evaluated and compared. Ball milling with magnetite not only improved the surface properties of the carbonaceous adsorbents, especially BC, but also introduced magnetic properties through mechanical extrusion. Furthermore, ball-mill extrusion increased the MB adsorption capacity of BC at all pH values by 14-fold, on average, but BC ball milled with magnetite had even greater MB adsorption capacity (27-fold, greater, on average). While ball milling of AC also improved its MB adsorption capacity (by almost 3-fold, on average), ball milling with magnetite did not further improve its MB adsorption capacity. All the magnetic adsorbents showed fast MB adsorption kinetics, reaching equilibrium within about 8 h. The Langmuir maximum MB adsorption capacity of the magnetic ball-milled BC (MBM-BC) was the highest (500.5 mg/g) among all the samples including the ones derived from AC. After five adsorption-desorption cycles, MBM-BC maintained about 80% MB removal capacity. The high MB adsorption capacity of MBM-BC was attributed to its increased surface area, opened pore structure, functional groups and aromatic CC bonds, which promoted π-π and electrostatic interactions. Findings from this study indicate that the magnetic ball-milled BC is a promising adsorbent due to its environmentally friendly synthesis, high efficiency, low cost, and convenience in operation.

17451. 题目: Alpine Hummocks Drive Plant Diversity and Soil Fertile Islands on the Tibetan Plateau
文章编号: N20031703
期刊: Wetlands
作者: Hui Zhao, Da Wei, Yan Yan, Jianbo Wu, Xiaodan Wang
更新时间: 2020-03-17
摘要: Earth hummocks are widely distributed in arctic, sub-Arctic and alpine regions and have important roles in determining plant diversity and the nutrient content of soils. We investigated the impact of the spatial heterogeneity on soil properties and plant communities caused by the hummocks on the Tibetan Plateau. The results indicated alpine hummocks created higher plant diversity and soil fertile island patterns under Kobresia Genus communities. Vegetation height, cover, above-ground and underground biomass, species richness and diversity at the top of well-developed hummocks were the significantly higher than those in the inter-hummocks and surrounding flat ground. The soil organic carbon content in surface soil layer (0-50 cm) at the hummock top was 154.6% and 172.3% higher than those in inter-hummock area and the flat ground, respectively. From the developing to well-developed stage, K. littledalei became the dominant population at hummock top instead of K. humilis, and fertile islands gradually formed with higher soil organic carbon and total nitrogen, lower soil moisture and wider soil temperature variation RDA analysis further indicated the interactions of plant community succession and soil fertile island could create positive feedbacks to nutrient-rich patches.

17452. 题目: Increase in Pb and Cd Adsorption by the Application of Peat in a Tropical Soil
文章编号: N20031702
期刊: Water, Air, & Soil Pollution
作者: Jéssica Pelinsom Marques, Valéria Guimarães Silvestre Rodrigues, Isabela Monici Raimondi, Jacqueline Zanin Lima
更新时间: 2020-03-17
摘要: Clayey soils have been used as liners at the base of waste deposits due to their geotechnical characteristics and capacity to adsorb metallic cations. However, a number of soils may not possess all required properties to ensure contaminant retention and therefore require additives. This study investigated whether the addition of commercial peat to a tropical residual soil (from the Ribeira Valley, Brazil) could improve its lead (Pb) and cadmium (Cd) adsorption capacity for its use as a liner in mining waste disposal. Pure soil and 10 and 20% soil-peat mixtures were compared. The application of peat increased the organic matter (OM) content (from 9 g kg−1 in soil to 58 g kg−1 in the 20% soil-peat mixture) and the cationic exchange capacity (CEC) (from 41.4 mmolc dm−3 in soil to 143.1 mmolc dm−3 in the 20% soil-peat mixture). Batch equilibrium test results revealed that the maximum Pb adsorption capacity of 623.6 μg g−1 also increased (to 1089.1 and 1270.0 μg g−1 in the 10 and 20% soil-peat mixtures, respectively). The soil Cd adsorption capacity of 261.2 μg g−1 increased to 304.0 and 631.3 μg g−1, respectively, with increasing peat proportions. The results suggest that peat can improve soil liner performance in waste deposits. Soil-peat mixtures are alternatives for minimizing potentially toxic metal contamination with available and low-cost materials.

17453. 题目: Short-term effects of biochar and Bacillus pumilus TUAT-1 on the growth of forage rice and its associated soil microbial community and soil properties
文章编号: N20031701
期刊: Biology and Fertility of Soils
作者: Khin Thuzar Win, Keiki Okazaki, Naoko Ohkama-Ohtsu, Tadashi Yokoyama, Yoshinari Ohwaki
更新时间: 2020-03-17
摘要: The synergistic effects of biochar (BC) and plant growth-promoting bacteria inoculant on crop growth and microbial communities' composition in the rhizosphere and endorhizosphere (roots) of forage rice were examined under a short-term greenhouse condition. We performed in-pot experiments to evaluate the effects of BC and Bacillus pumilus strain TUAT-1 inoculant (Bio), both alone and in combination (BB), on the growth and microbial community of rhizosphere and roots in forage rice at 2 and 5 weeks after transplantation. At both growth stages, rice growth was improved by either BC or Bio alone. TUAT-1 was readily detected in rhizosphere with greater abundance following BB treatment than after Bio treatment alone. The bacterial communities of the rhizosphere, non-rhizosphere soil (un-planted bulk), and endorhizosphere of roots were determined using next-generation sequencing. Compared with the microbial community and diversity in the rhizosphere and endorhizosphere of roots, BC had greater effects on rhizosphere than on endorhizosphere, whereas Bio more effectively altered the microbial communities of the endorhizosphere layer of roots. Soil properties (pH and total N, exchangeable NH4-N, and K levels) were improved by either BC or Bio alone, suggesting that the changes of soil microbial communities might occur directly or indirectly as an effect of the alteration of soil physico-chemical properties. Overall, the result from this study suggests that biochar amendment and TUAT-1 inoculant have the potential to enhance growth and nutrient uptake in forage rice, and they depend on soil physico-chemical properties and the alteration of native microbial communities' composition.

17454. 题目: Persistence of native and bio-derived molecules of dissolved organic matters during simultaneous denitrification and methanogenesis for fresh waste leachate
文章编号: N20031607
期刊: Water Research
作者: Junjie Qiu, Fan Lü, Hua Zhang, Yulong Huang, Liming Shao, Pinjing He
更新时间: 2020-03-16
摘要: Biological treatment of wastewater always leaves plenty of refractory dissolved organic matters (DOM) in effluents, specifically for fresh waste leachate. Aiming at comprehending the production and removal of these compounds, this study investigated DOM transformation in a simultaneous denitrification and methanogenesis with activated sludge (SDM-AS) system with NO3−/NO2− backflow for raw fresh leachate. Chemical oxygen demand (COD) was reduced to 854 ± 120 mg/L from 63000 ± 470 mg/L, and total nitrogen (TN) decreased from 2500 ± 647 mg/L to 404 ± 75 mg/L, during an operation of 440 days. The SDM reactor was fed at organic loading rate of 6.70 kgCOD/(m3·d) to generate 2.52 L CH4/(L·d). Molecular information of leachate DOM was acquired by using ultra-performance liquid chromatography coupled with Orbitrap mass spectrometry. A DOM classification based on Venn diagram was proposed to divide leachate DOM into seven categories. It revealed that 76–84% of final effluent DOM stemmed from biological derivation. Posteriori non-target screening showed anthropogenic micropollutants, e.g. phosphate flame retardants and industrial agents, probably contributed to the remnant native inert DOM in the effluent at the levels of 5–200 μg/L. DOM Classification also showed a portion of bio-derived DOM can be completely removed by SDM-AS processes, while the rest bio-derived DOM can be partially removed depending on DOM nature and the recirculation ratio. The removal and production rate of specific bio-derived DOM in respective SDM and AS units theoretically satisfied a hyperbolical and dual relationship in terms of mass balance. The persistence of each DOM category was sorted. These results showed anaerobic degradation could be a promising approach to reduce aerobic bio-derived DOM.

17455. 题目: Sustainable energy from waste organic matters via efficient microbial processes
文章编号: N20031606
期刊: Science of The Total Environment
作者: Rajesh K. Srivastava, Nagaraj P. Shetti, Kakarla Raghava Reddy, Tejraj M. Aminabhavi
更新时间: 2020-03-16
摘要: This review emphasizes utilization of waste organic matters from water bodies and soil sources for sustainable energy development. These organic waste matters (including microplastics) from a variety of environmental sources have created a big challenge to utilize them for energy development for human needs, maintaining a cleaner environment and thereby, producing useful bioproducts (sustainable bioenergy or other primary metabolites). Anaerobic digestions as well as other effective wastewater treatment approaches are discussed. From the water bodies, waste organic matter reduction can be achieved by a reduction of chemical oxygen demand and biological oxygen demand after the waste treatment. Other forms of organic waste matter are available in the form of agro wastes or residues (stalk of wheat or rice, maize, corn etc.) due to crop cultivation, which are generally burnt into ashes. Such wastes can be utilized for bioenergy energy production, which would help for the reduction of climate changes or other toxic gases. Hydrogen, bioelectricity, ethanol, butanol, methane and algal diesel or other types of fuel sources would help to provide sustainable source of bioenergy that can be produced from these wastes via degradation by the biological processes. This review will discuss in depths about the sustainable nature of organic matters to produce clean energy via application of efficient biological methods to maintain a clean environment, thereby providing alternative options to fossil energy fuels.

17456. 题目: Kinetic effects of anaerobic staging and aeration rates on sequencing batch moving bed biofilm reactors: Carbon, nitrogen, and phosphorus treatment of cheese production wastewater
文章编号: N20031605
期刊: Chemosphere
作者: Alexandra Tsitouras, Onita Basu, Nour Al-Ghussain, Robert Delatolla
更新时间: 2020-03-16
摘要: The food and beverage industry produces wastewaters containing high concentrations of organic carbon and nutrients, which when discharged leads to eutrophication and algal blooms. Given recent stringencies in effluent regulations, industries are required to treat their wastewater on-site. There is a critical need for compact, high-rate, cost-effective wastewater technologies to treat industrial wastewaters, such as the sequencing batch moving bed biofilm reactor. The aim of this study is to investigate the potential and evaluate the performance of the sequencing batch moving bed biofilm reactor cycling between anaerobic and aerobic stages to treat high-strength food and beverage wastewaters. Specifically, this study focuses on the effects of anaerobic staging times and enhanced aeration on the removal of carbon, nitrogen, and phosphorous from cheese production wastewaters. Increasing anaerobic staging times was found to improve the removal rates of carbon beyond previously reported moving bed biofilm reactor results. Increasing the anaerobic stage however decreased the total nitrogen removal, with organic nitrogen undergoing ammonification during the anaerobic stage. This study demonstrates an optimum anaerobic staging time of 138 min; with a carbon removal rate of 31.1 g-sCOD·m−2d−1 and a nitrogen removal rate of 1.3 g-N·m−2d−1. Enhanced aeration was found to be detrimental to phosphorous removal, where a moderate aeration rate demonstrated a net total phosphorous removal of approximately 22 mg-P·l−1 with the phosphorous-content of the suspended solids being approximately 4%. Finally, the sequencing batch moving bed biofilm reactor shows potential for on-site treatment of carbon, nitrogen, and phosphorous from cheese production wastewater.

17457. 题目: Qualitative and quantitative analysis of source for organic carbon and nitrogen in sediments of rivers and lakes based on stable isotopes
文章编号: N20031604
期刊: Ecotoxicology and Environmental Safety
作者: Qingjun Guo, Chunyu Wang, Rongfei Wei, Guangxu Zhu, Meng Cui, Chukwunonso Peter Okolic
更新时间: 2020-03-16
摘要: Sediment is the most dominant reservoir of organic pollutants in the aquatic environment. Understanding carbon and nitrogen sources in sediments and factors that controls distribution enhances our understanding of biogeochemical cycles of carbon and nitrogen. Different end-members and surface sediments of rivers and sediments profiles of lakes were collected. The concentrations of TOC and TON and their δ13C and δ15N were studied for qualitative and quantitative analysis of natural and anthropogenic sources. The results show that TOC and TON concentrations of the sediments from rivers range from 0.63% to 10.83% and 0.06%–0.86%, respectively, indicating substantial great environmental risks in these rivers. The concentrations of TOC and TON for the four sediment profiles below the 5 cm, increase in the order of Miyun < Chuidiao < Qunming < Houhai, as influenced by their respective environment condition. Moreover, water quality was quite good and there was no risk of eutrophication in Miyun reservoir. δ13Corg and δ15Norg in surface sediments of the studied 18 rivers range from −27.2‰ to −24.9‰ and −2.2‰ to +10.9‰, respectively. Based on a simple δ13C-based end-member mixing and a C/N ratio model, organic matter in the surface sediments of these rivers were mainly derived from sewage and C3 plant. In addition, the sources of organic matter differed in each layer of the four sediment profiles. This study provides a reliable method for qualitative and quantitative identification of the source of organic matter in sediments, and offers theoretical basis for better management of rivers and lakes.

17458. 题目: Geochemical characterization of the depositional environment of Paleocene and Eocene sediments of the Tertiary Central Basin of Svalbard
文章编号: N20031603
期刊: Chemical Geology
作者: M. Doerner, U. Berner, M. Erdmann, T. Barth
更新时间: 2020-03-16
摘要: The Tertiary Central Basin (CTB) of Svalbard has been studied extensively in the past because it contains sediments from the Paleocene Eocene Thermal Maximum (PETM). Previous studies have found that a negative carbon isotopic extrusion (CIE) is presents without showing elevated concentration of organic carbon. In this study we extend the record of the CTB with a comprehensive inorganic and organic geochemical data set based on the sediments encountered in the research well BH 10–2008, comprising almost 1100 m of cored sediments. Major and trace elements analyses in combination with mineralogical, carbon isotopic, total organic carbon (TOC), and total sulphur measurements were used to reconstruct the depositional environments of the lower Paleocene Basilika Fm. up the Eocene Aspelintoppen Fm. Several depositional environments have been interpreted, which are consistent with the sedimentological interpretation of the respective well section. Back-calculation of the initial organic carbon concentration shows that bacterial sulphate reduction had a major impact on the persevered organic carbon inventory of the lower Basilika Fm. and of the Paleocene/Eocene transition section. Based on organic carbon loss introduced by bacterial decay, as well as measured isotopic composition, we estimate an initial isotopic composition of the evaluated sediments which helps to elucidate on the fate of labile organic matter and explains the unusually low organic carbon inventory of the Paleocene/Eocene transition sediments.

17459. 题目: Pasture degradation impact on soil carbon and nitrogen fractions of alpine meadow in a Tibetan permafrost region
文章编号: N20031602
期刊: Journal of Soils and Sediments
作者: Zi-Qiang Yuan, Qing-Bai Wu, Xin Song, Xiao-Jin Jiang, Si-Ru Gao, Qing-Feng Wang, Guo-Yu Li
更新时间: 2020-03-16
摘要: Purpose Knowledge of the effects of pasture degradation on soil organic carbon (SOC) and nitrogen (N) fractions in permafrost soils on the Tibetan Plateau is limited. The aims of this study were (1) to evaluate the changes in SOC and N contents in density fractions under Kobresia pasture due to degradation and (2) to explore the contributions of the changes of SOC and N in density fractions to the changes of SOC and N in whole soil. Materials and methods The impact of Kobresia pasture degradation on SOC and N fractions was investigated in the permafrost region of the Tibetan Plateau. A continuously degraded pasture was identified and classified into three categories of vegetation cover according to their degrees of degradation (i.e., vegetation cover decline from 90% ± 6.6% to 70% ± 8.3% and 45% ± 8.7%). The SOC and N fractions were separated by using the density separation method. Results and discussion The Kobresia pasture degradation significantly decreases SOC and N contents and stocks in soils. The SOC and N contents in the whole soil were positively correlated with the SOC and N contents in the light and heavy fractions (p < 0.001, respectively). The SOC and N contents were significantly correlated with soil pH and the contents of soil moisture, clay, silt, and sand. The ratio of SOC to total N in the whole soil was positively correlated with the ratio of SOC to N in heavy fractions (p < 0.001) rather than the ratio of SOC to N in light factions (p > 0.05). When pasture degraded from vegetation covers 90% to 45%, SOC stock at 0–40-cm soil layer decreased by 28.7% and N stock decreased by 39.2% in the whole soil; 56.6% and 47.6%, respectively, in the light fractions and 14.3% and 40.6%, respectively, in the heavy fractions. The depletion rates of N were higher than those of SOC in the heavy fractions and whole soil. At all sites, more than 80% of the SOC and N stocks were protected in heavy fractions. Conclusions These results indicate that a decoupling depletion of SOC and soil N appeared with the Kobresia pasture degradation in the permafrost region of the Tibetan Plateau. The Kobresia pasture degradation affects the SOC and N fractions differently and thus regulates soil carbon and N cycling in the permafrost soils on the Tibetan Plateau.

17460. 题目: The effect of post-pyrolysis treatment on waste biomass derived hydrochar
文章编号: N20031601
期刊: Waste Management
作者: L. Bahcivanji, G. Gascó, J. Paz-Ferreiro, A. Méndez
更新时间: 2020-03-16
摘要: Hydrochars are materials with a promising future, as their high carbon content and porosity renders them suitable for uses including peat substitutes, soil remediation and carbon adsorbent precursors. Combining hydrothermal carbonization and pyrolysis offers the prospect to provide advanced materials with a higher porosity and carbon content. This approach would mitigate drawbacks associated to hydrochars, including phytotoxicity. This research studied the influence of pyrolysis temperature and heating time on the resulting properties of chars made from hydrothermal carbonization of biomass wastes at 200 °C for 4 h and compared them to biochars that had not received any prior hydrothermal carbonization. Interestingly, hydrochar followed by pyrolysis was able to result in phytostimulation, while, when only pyrolysis was carried out, phytotoxicity was eliminated, but no phytostimulant effect was observed. In addition, the results indicated that the higher and longer the pyrolysis temperature (from 350 to 550 °C) and duration time (from 1 to 5 h), respectively, the more microporosity was generated, while phytotoxicity was reduced. In addition, aromaticity and thermal stability significantly increased with pyrolysis treatment. Consequently, hydrochars improve their properties and offer more potential for environmental applications after a pyrolysis post-treatment.